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The colour-changing comet

April 8, 2016

[Image: thecolourcha.jpg]The colour-changing comet. Credit: ESA/ATG medialab; Data: ESA/Rosetta/VIRTIS/INAF-IAPS/OBS DE PARIS-LESIA/DLR; G. Filacchione et al (2016)

Rosetta's comet has been seen changing colour and brightness in front of the ESA orbiter's eyes, as the Sun's heat strips away the older surface to reveal fresher material.

Rosetta's Visible and InfraRed Thermal Imaging Spectrometer, VIRTIS, began to detect these changes in the sunlit parts of Comet 67P/Churyumov–Gerasimenko – mostly the northern hemisphere and equatorial regions – in the months immediately following the spacecraft's arrival in August 2014.

A new paper, published in the journal Icarus, reports on the early findings of this study, up to November 2014, during which time Rosetta was operating between 100 km to within 10 km of the comet nucleus. At the same time, the comet itself moved along its orbit closer to the Sun, from about 542 million km to 438 million km.
VIRTIS monitored the changes in light reflected from the surface over a wide range of visible and infrared wavelengths, as an indicator of subtle changes in the composition of the comet's outermost layer.
When it arrived, Rosetta found an extremely dark body, reflecting about 6% of the visible light falling on it. This is because the majority of the surface is covered with a layer of dark, dry, dust made out of mixture of minerals and organics.
[Image: 1-thecolourcha.jpg]
Four-image NAVCAM mosaic of Comet 67P/Churyumov-Gerasimenko, using images taken on 19 September 2014 when Rosetta was 28.6 km from the comet. Credit: ESA/Rosetta/NAVCAM
Some surfaces are slightly brighter, some slightly darker, indicating differences in composition. Most of the surface is slightly reddened by organic-rich material, while the occasional ice-rich material shows up as somewhat bluer.
Even when Rosetta first rendezvoused with the comet far from the Sun, ices hidden below the surface were being gently warmed, sublimating into gas, and escaping, lifting some of the surface dust away and contributing to the comet's coma and tail.
VIRTIS shows that as the 'old' dust layers were slowly ejected, fresher material was gradually exposed. This new surface was both more reflective, making the comet brighter, and richer in ice, resulting in bluer measurements.
On average, the comet's brightness changed by about 34%. In the Imhotep region, it increased from 6.4% to 9.7% over the three months of observations.
over the three months of observations.
[Image: thecolourcha.png]
Mosaic of six OSIRIS narrow-angle camera images of the geologically diverse Imhotep region on Comet 67P/Churyumov–Gerasimenko. The mosaic comprises images taken on 3 August, 25 August and 5 September 2014 from distances of 272 km, 52 km and 43 km from the comet centre, respectively. As such, the image scale varies from 5 m/pixel to 0.8 m/pixel. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
"The overall trend seems to be that there is an increasing water-ice abundance in the comet's surface layers that results in a change in the observed spectral signatures. In that respect, it's like the comet is changing colour in front of our eyes," says Gianrico Filacchione, lead author of the study.

"This evolution is a direct consequence of the activity occurring on and immediately beneath the comet's surface. The partial removal of the dust layer caused by the start of gaseous activity is the probable cause of the increasing abundance of water ice at the surface."
"The surface properties are really dynamic, changing with the distance from the Sun and with the levels of comet activity," adds Fabrizio Capaccioni, VIRTIS principal investigator.
"We've started analysing the subsequent datasets and can already see that the trend continues in the observations made beyond November 2014."
"The evolution of surface properties with activity has never been observed by a cometary mission before and is a major science objective of the Rosetta mission," says Matt Taylor, ESA's Rosetta Project Scientist.
"It is great to see science papers being published directly addressing this topic and we're looking forward to seeing how things have changed over the entire mission."
[Image: 1x1.gif] Explore further: Rosetta measures comet's temperature
More information: Gianrico Filacchione et al. The global surface composition of 67P/CG nucleus by Rosetta/VIRTIS. (I) Prelanding mission phase, Icarus (2016). DOI: 10.1016/j.icarus.2016.02.055 
Journal reference: Icarus [Image: img-dot.gif] [Image: img-dot.gif]
Provided by: European Space Agency

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Team identifies clathrate ices in comet 67P

April 8, 2016

[Image: swriledteami.png]
Southwest Research Institute scientists led an international team studying the composition of comet 67P’s coma to better understand the ice structures and the possible origin of its nucleus. The team found evidence of water ice clathrates that could indicate the comet formed closer to the Sun than originally thought. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
For decades, scientists have agreed that comets are mostly water ice, but what kind of ice—amorphous or crystalline—is still up for debate. Looking at data obtained by ESA's Rosetta spacecraft in the atmosphere, or coma, around comet 67P/Churyumov-Gerasimenko, scientists at Southwest Research Institute (SwRI) are seeing evidence of a crystalline form of ice called clathrates.

"The structure and phase of the ice is important because it tells us a lot about how and where the comet may have formed," says Dr. Adrienn Luspay-Kuti, a research scientist in SwRI's Space Science and Engineering Division. She is the lead author of a paper titled "The presence of clathrates in comet 67P/Churyumov-Gerasimenko" published in the April 8 issue of the journal Science Advances. "If the building blocks of 67P were predominantly crystalline ices and clathrates, then 67P likely agglomerated from chunks of ice closer to the Sun. The protosolar nebula closer to the Sun experienced higher temperatures and more turbulence where crystalline ices could form as the nebula cooled. More pristine amorphous ices likely dominated the colder outskirts of the rotating disk of dust and gas that surrounds the core of a developing solar system."

Amorphous water ice efficiently traps large amounts of volatile compounds, which are released simultaneously upon warming. Water clathrates are crystalline structures containing gas molecules. The volatiles locked inside the water actually create the stable clathrate structure. These structures release gases at characteristic temperatures, dependent on the gas-phase volatile locked inside the clathrate. Luspay-Kuti led an international team of cometary experts that interpreted Rosetta spacecraft data, and found that the observed outgassing pattern indicates the nucleus of 67P contains clathrates.

"Without direct sampling of the nucleus interior, evaluating the composition of the coma provides the best clues about the ice structure and, as a result, the possible origin of cometary nuclei," said Luspay-Kuti. "Thought to closely reflect the composition of the building blocks of our solar system, comets carry important information about the prevalent conditions in the solar nebula before and after planet formation. These small icy bodies help us understand the big picture."

The multi-institute team of cometary scientists analyzed mass spectrometer data from the southern region of 67P from September to October 2014, before equinox. 67P is a Jupiter family comet thought to originate from the Kuiper Belt. Scientists are comparing these new data with data from the flyby of Hartley 2—considered cometary kin in family and origin to 67P—and finding correlations. If these comets formed closer to the Sun than originally thought, these data could help refine solar system formation models.

[Image: 1x1.gif] Explore further: Rosetta data reveals more surprises about comet 67P

More information: "The presence of clathrates in comet 67P/Churyumov-Gerasimenko" 

Journal reference: Science Advances [Image: img-dot.gif] [Image: img-dot.gif]
Provided by: Southwest Research Institute

Read more at:[url=]
Yep, plastered in decidedly non-geological objects. I noticed several rectangular objects with four square holes in the end, not all in the same pic either.
400m across isn't a bad size for a space colony, perhaps bigger for them than us. Maybe back then humans were smaller - animal species that live under constrained conditions often become smaller, for instance examples living on an island compared to fellow creatures living on a nearby continental mainland.
Maybe cramming themselves into arcologies and possibly not having a friendly planet on which to stretch their legs left our ancestors a bit more economical on resources - like living space - than we are today.
Wickramasinghe will have his day.

Comet contains glycine, key part of recipe for life
May 27, 2016

An important amino acid called glycine has been detected in a comet for the first time, supporting the theory that these cosmic bodies delivered the ingredients for life on Earth, researchers said Friday.

Glycine, an organic compound contained in proteins, was found in the cloud around Comet 67P/Churyumov-Gerasimenko by the European Space Agency's probe, Rosetta, said the study in the journal Science Advances.
The discovery was made using an instrument on the probe, called the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) mass spectrometer.
"This is the first unambiguous detection of glycine in the thin atmosphere of a comet," said lead author Kathrin Altwegg, principal investigator of the ROSINA instrument at the Center of Space and Habitability of the University of Bern.
In addition to the simple amino acid glycine, the instrument also found phosphorus. The two are key components of DNA and cell membranes.
Glycine has been detected in the clouds around comets before, but in previous cases scientists could not rule out the possibility of Earthly contamination.
This time, however, they could, because the mass spectrometer directly detected the glycine, and there was no need for a chemical sample preparation that could have introduced contamination.
"The multitude of organic molecules already identified by ROSINA, now joined by the exciting confirmation of fundamental ingredients like glycine and phosphorus, confirms our idea that comets have the potential to deliver key molecules for prebiotic chemistry," said Matt Taylor, Rosetta project scientist of the European Space Agency ESA.
"Demonstrating that comets are reservoirs of primitive material in the Solar System, and vessels that could have transported these vital ingredients to Earth, is one of the key goals of the Rosetta mission, and we are delighted with this result."
Scientists have long debated the question of whether comets and asteroids brought the components of life to Earth by smashing into oceans on our planet.
More than one hundred molecules have been detected on comets and in their dust and gas clouds, including many amino acids.
Previous data from Rosetta has shown that water on Comet 67P/C-G is significantly different from water on Earth, suggesting that comets did not play as big a role in delivering water as once thought.
However, the latest finding shows "they certainly had the potential to deliver life's ingredients," said a statement by the University of Bern.
[Image: 1x1.gif] Explore further: Mystery of where Earth's water came from deepens: Comet water is different
Journal reference: Science Advances

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Two Phony actors
Encounter their detractors.
Poetic twaddle-waddle quacked here.
lincoln banned troll youareaduck  bad psi RCHtelephoney guy
Scheeres' facts for Shear factor.


Pastewka and his team looked at the surface of spheres on the atomic level. They studied how the contact areas—those irregular peaks and valleys—interacted with the surfaces they were pushed against. By running simulations, Pastewka was able to formulate a mathematical expression that demonstrates how spheres with different types of peaks and valleys will change when they're met with various amounts of pressure.
While it is possible to create a near perfectly spherical object, most scientists can't afford to do so. Knowing how to correct the imperfections mathematically is the cheapest and most plausible way to tackle this problem.

Read more at:

Solves for this:

Scheeres said there are several factors that can cause comet nuclei to spin faster. During flybys of the sun or Jupiter, for example, periodic comets like 67P can get torqued by gravity, causing them to either spin up or spin down. The spin also can be affected by periodic comet "outgassing," when icy compounds like carbon dioxide and ammonia shift directly from a frozen state to gaseous state and blow off the surface.

The models run by the team showed that if 67P's spin is increased to less than seven hours per rotation, the head will pop off, said Scheeres. So what happens then?

"The head and body aren't going to be able to escape from each other," he said. "They will begin orbiting each other, and in weeks, days or even hours they will come together again during a slow collision, creating a new comet nucleus configuration."

Read more at:

and is proved by this:

Versatile tool measures changes in ice behavior over wide temperature range—Earth's glaciers to Saturn's moon

May 31, 2016

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Schematic illustration of the apparatus developed by researchers at Lamont-Doherty Earth Observatory at Columbia University to study ice over a wide range of temperatures. Credit: Lamont-Doherty Earth Observatory's Rock and Ice Mechanics Lab
Much of modern life is deeply impacted by the behavior of ice.

Now, new work from a team at Lamont-Doherty Earth Observatory at Columbia University in Palisades, New York, gives insights into what is happening inside ice. The team has developed an apparatus to meet the growing need for measuring ice as it changes in response to external forces, a process ice scientists call "deformational behaviors.'' These forces occur on Earth in glacial ice as it flows due to gravity, and in space as icy satellite bodies, such as the moons of Jupiter and Saturn, respond to tidal forces from their parent bodies. These planetary icy satellites greatly intrigue scientists with their potential to hold vast oceans under the ice, and possibly, to support life.

The Lamont-Doherty team's report on their device—called a cryogenic deformation apparatus—appears in the current issue of the Review of Scientific Instruments.

Read more at:

Read all Three.

Study shows how comets break up, make up

June 1, 2016

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A new study led by Purdue and CU-Boulder researchers shows that comet splitting and reuniting may be fundamental to comet evolution. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
For some comets, breaking up is not that hard to do. A new study led by Purdue University and the University of Colorado Boulder indicates the bodies of some periodic comets - objects that orbit the sun in less than 200 years - may regularly split in two, then reunite down the road.

In fact, this may be a repeating process fundamental to comet evolution, according to the study, which is being published in Nature on June 1.

The team, led by Purdue postdoctoral fellow Masatoshi Hirabayashi and CU-Boulder Distinguished Professor Daniel Scheeres, studied several comets, primarily a bizarre rubber duck-shaped object known as 67P/Churyumov-Gerasimenko (67P). Images of 67P show two cracks, each longer than an American football field, on the comet's neck that connects its two larger lobes.

In order to reconstruct the past life of 67P, the team used numerical models in which the spin rate was cranked up from its roughly one rotation every 12 hours today to one rotation every 7 to 9 hours. The models showed the faster spin would lead to more stress and the formation of two similar cracks on the neck of 67P in the same location.

"Our spin analysis predicted exactly where these cracks would form," said Scheeres of CU-Boulder's aerospace engineering sciences department. "We now have a new understanding of how some comets may evolve over time."

Often referred to as "dirty snowballs," comets are made of ice, rocks and dust. Comet 67P is "bilobed" meaning it has two larger parts connected by a thinner neck.

Scheeres said there are several factors that can cause comet nuclei to spin faster. During flybys of the sun or Jupiter, for example, periodic comets like 67P can get torqued by gravity, causing them to either spin up or spin down. The spin also can be affected by periodic comet "outgassing," when icy compounds like carbon dioxide and ammonia shift directly from a frozen state to gaseous state and blow off the surface.

The models run by the team showed that if 67P's spin is increased to less than seven hours per rotation, the head will pop off, said Scheeres. So what happens then?

"The head and body aren't going to be able to escape from each other," he said. "They will begin orbiting each other, and in weeks, days or even hours they will come together again during a slow collision, creating a new comet nucleus configuration."

This pattern could go on for the life of the comet, said Scheeres.

Bilobed comets may turn out to be fairly common. Of the seven comets that have been imaged in high resolution by astronomers, five of those - including P67 and Comet Halley - are bilobed, said Scheeres. Studies of the bilobed comets by the team indicate they all are similar in their volume ratios between each lobe, meaning they probably go through the same break-up/make-up cycles as 67P.

Discovered in 1969 and visited by the European Space Agency's Rosetta spacecraft in 2014, 67P is roughly 2.5 miles on a side and orbits the sun every 6.5 years. The team showed that the comet's spin rate can change chaotically, driven by outgassing events and its changing orbit driven by flybys of Jupiter.

To show how this comet-sun interaction affected the past evolution of 67P's spin period, the researchers numerically modeled 1,000 comet "clones" of 67P under varying conditions going back 5,000 years. Five thousand years was selected because it is the approximate lifetime of a "Jupiter family comet" like 67P, whose orbit is affected by the gravity of not only the sun but the gas giant Jupiter, the largest planet in our solar system, said Scheeres.

Periodic comets like 67P are thought to originate in the Kuiper Belt, a vast region beyond Neptune's orbit harboring billions of comets and icy moons. The team hypothesized that the repeated break-up and make-up of bilobed comets may have caused them to erode too much to have survived their journeys into the inner solar system 4 billion years ago when it was a shooting gallery of asteroids, moons and protoplanets.

Other study authors include Assistant Professor Jay McMahon of CU-Boulder, Steven Chesley of the Jet Propulsion Laboratory in Pasadena and Simone Marchi of the Southwest Research Institute Planetary Science Directorate in Boulder. Purdue's Hirabayashi received his doctorate at CU-Boulder under Scheeres in 2015.

Scheeres is the radio science team leader for NASA's OSIRIS-Rex mission, now slated to launch in September from Florida to visit the near-Earth asteroid, Bennu.

[Image: 1x1.gif] Explore further: How big is Rosetta's comet?

More information: Fission and reconfiguration of bilobate comets as revealed by 67P/Churyumov–Gerasimenko, 

Journal reference: Nature [Image: img-dot.gif] [Image: img-dot.gif]
Provided by: University of Colorado at Boulder

Read more at:[url=]

improv eyes wuz here.
Europe's comet orbiter back after 'dramatic' silence
June 2, 2016 by Mariëtte Le Roux

[Image: rosettaalong.jpg]
Rosetta, along with its space probe Philae, is being used to carry out a detailed study of comet 67P/Churyumov-Gerasimenko
Europe's trailblazing spacecraft Rosetta has resumed its exploration of a comet hurtling through the Solar System after a "dramatic weekend" in which contact with Earth was lost for nearly 24 hours, mission control said Thursday.

The orbiter's navigation system, which works by tracking the position of stars, likely became confused after mistaking dust particles near the comet surface for faraway heavenly bodies, the European Space Agency (ESA) said.
"We lost contact with the spacecraft on Saturday evening for nearly 24 hours," mission manager Patrick Martin said on the agency's Rosetta blog.
In orbit around comet 67P/Churyumov-Gerasimenko, Rosetta is now some 428 million kilometres (266 million miles) from Earth and 468 million km (291 miles) from the Sun—somewhere between the orbits of Mars and Jupiter—travelling at a speed of 17.65 km per second (10.96 m/s).
"Preliminary analysis by our flight dynamics team suggests that the star trackers locked onto a false star," said Martin, as Rosetta descended to within five kilometres (3.1 miles) of the frozen space rock blasting out jets of icy dust.
The spacecraft, perhaps best known as the mothership of surface probe Philae, entered "safe mode" as communication with Earth was severed, and switched off its science instruments, including cameras, radar, and chemical gas analysers.
Ground controllers sent "blind" commands to the orbiter, without knowing at first whether they were received or executed, to realign the star trackers which were subject to a similar dust-related mishap in April 2015.
"It was an extremely dramatic weekend," said spacecraft operations manager Sylvain Lodiot.
Contact was reestablished by Monday and the spacecraft's location pinpointed, which allowed flight manoeuvres to be performed to move it away from the comet, into a 30 km orbit.
"I confirm the spacecraft status is back to normal mode, with instruments back in science operations," Martin told AFP on Thursday.
[Image: 1-aphotoreleas.jpg]
A photo released by the European Space Agency (ESA) in November 2014 shows an image taken by Rosetta's lander Philae
Final resting place
Rosetta, with Philae riding piggyback, arrived at 67P in August 2014 after a ten-year, 6.5-billion kilometre journey from Earth.
In November that year, it sent down Philae, a 100-kilogramme (220-pound) lab equipped with 10 instruments for comet sniffing and prodding.

After bouncing several times, the robot lab ended in a ditch shadowed from the Sun's battery-replenishing rays. But it managed to run about 60 hours of experiments and send home reams of valuable data before running out of energy and entering standby mode.
As 67P neared the Sun on its elongated orbit, Philae emerged from hibernation in June 2015 and sent a two-minute message to Earth via its mothership.
The lander went permanently silent in July 2015 after eight intermittent communications with Earth.
The 1.3-billion-euro ($1.45-billion) mission was conceived to unravel the secrets of comets, believed to be time capsules from the birth of the Solar System.
It is meant to wind down in September, reuniting Rosetta with Philae on the surface of 67P.
The weekend's events served as "a stark reminder of the dangers associated with flying close to the comet," said the ESA blog.
"The last six weeks of the mission will be far more challenging for flight dynamics than deploying Philae to the surface was in November 2014, and it is always possible that we could get another safe mode when flying close to the comet like this," explained Sylvain.
"However, the very final sequence where Rosetta makes a controlled impact on the surface of the comet should not be affected by such star tracker issues as we plan to take them out of the attitude and orbit control system loop."
The provisional plan for laying Rosetta to rest, said the agency, was to place it on the smaller lobe of the rubber duck-shaped comet—near Philae's targeted landing site dubbed Agilkia.

This will "most likely" happen on September 30.

[Image: 1x1.gif] Explore further: Europe's Rosetta craft swoops for close look at comet

Read more at:[/url][url=]
Rosetta, Philae to reunite on comet for Sept 30 mission end Cry
June 30, 2016

[Image: 1-rosettaalong.jpg]
Rosetta, along with its space probe Philae, is being used to carry out a detailed study of comet 67P/Churyumov-Gerasimenko
Europe's trailblazing Rosetta spacecraft will end its mission on September 30, reuniting with robot lab Philae on the surface of a comet hurtling through the Solar System, mission control said Thursday.

"30 September will mark the end of spacecraft operations," Rosetta project scientist Matt Taylor said.
"The mission is coming to an end as a result of the spacecraft's ever-increasing distance from the Sun and Earth", said a statement by the European Space Agency.
"It is heading out towards the orbit of Jupiter, resulting in significantly reduced solar power to operate the craft and its instruments... Rosetta is reaching the end of its natural life."
Rosetta, perhaps best known as the mothership of comet lander Philae, whose exploits in an alien world were followed by people around the world, was hoisted into space in March 2004.
With Philae riding piggyback, it arrived at comet 67P/Churyumov-Gerasimenko in August 2014 after a ten-year, 6.5-billion kilometre journey.
In November that year, it sent down Philae, a 100-kilogramme (220-pound) lab equipped with 10 instruments for comet sniffing and prodding.
After bouncing several times, the robot lab ended in a ditch shadowed from the Sun's battery-replenishing rays. But it managed to run about 60 hours of experiments and send home reams of valuable data before running out of energy and entering standby mode.
As 67P neared the Sun on its elongated orbit, Philae emerged from hibernation in June 2015 and sent a two-minute message to Earth via Rosetta.
The lander went permanently silent in July 2015 after eight intermittent communications with Earth.
The 1.3-billion-euro ($1.4-billion) mission was conceived to unravel the secrets of comets, believed to be time capsules from the birth of the Solar System.
[Image: 1x1.gif] Explore further: Comet mission in bid to contact dormant Philae probe

Read more at:[url=][/url]
Just watched this with Logan.

He doesn't quite get it that Philae is non-resposive because of the recurring flashback scenes that confuses him a bit.

He has that sense of wonder.

I'll replay it for him over the next few days ... along with all the other awesome ESA cartoons!!!

What a great series Arrow  perfect for a grandkid. 

For the non  ~3.3 year olds in the room...

where philae "Left" off is Rite where is was?

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Farewell Philae: Earth severs link with silent comet probe (Update)
July 27, 2016

[Image: 2-aphotoreleas.jpg]
A photo released by the European Space Agency (ESA) in November 2014 shows an image taken by Rosetta's lander Philae on the surface of Comet 67P/Churyumov-Gerasimenko
Earth bid a final farewell to robot lab Philae on Wednesday, severing communications after a year-long silence from the pioneering probe hurtling through space on a comet.

Writing an extraordinary chapter in space history, the washing machine-sized craft was the first to land on a comet—primeval rubble from the formation of the Solar System.
Philae sent home reams of data garnered from sniffing, tasting and prodding its new alien home hundreds of millions of kilometres (miles) from Earth.
Its plucky exploits captured the imagination of children, and many adults, who followed its successes and tribulations via Twitter and an animated cartoon series.
But after more than 12 months without news, it was decided to preserve all remaining energy available to Philae's orbiting mothership Rosetta, the European Space Agency (ESA) announced in a blog entitled: "Farewell, silent Philae".
Rosetta will remain in orbit around comet 67P/Churyumov-Gerasimenko for another two months.
It will crashland on September 30 to join Philae in their final resting place, concluding an historic quest for cometary clues to the origins of life on Earth.
"Today communication with Philae was stopped," Andreas Schuetz of German space agency DLR told AFP from ground control in Cologne on Wednesday.
"This is the end of a... fascinating and successful mission for the public and for science."
Part of a 1.3-billion-euro ($1.4-billion) ESA mission, Philae was launched into space in March 2004, riding piggyback on Rosetta.
The pair travelled some 6.5 billion km (four billion miles)—aided by gravity boosts from Earth and Mars—before entering 67P's orbit in August 2014.
Three months later, Rosetta sent the 100-kilogramme (220-pound) probe down to the comet surface—starting a nail-biting deep-space saga.
Philae's harpoons failed to fire into the comet surface, and it bounced several times.
Abandoning hope
The tiny robot ended up in a ditch shadowed from the Sun's battery-replenishing rays, but managed to run about 60 hours of experiments and send home valuable data before entering standby mode.
As 67P neared the Sun on its elongated orbit, Philae got a battery boost and emerged from hibernation in June 2015, sending a two-minute message via Rosetta, eliciting great excitement on Earth.
But after eight intermittent communications, the lander fell permanently silent on July 9, 2015.
Rosetta has continued to monitor the comet, but without catching sight of its long-lost charge, even from as close as 10 km away.
In February, ground controllers said they believed Philae was in eternal hibernation—though they opted to keep an ear open just in case.
Wednesday's final break, at 0900 GMT, means "abandoning all hope of receiving anything more from Philae," said Philippe Gaudon of France's CNES space agency.
"It's time for me to say goodbye," said Philae's Twitter account, announcing communications "will be switched off forever..."
As the comet moves further and further away from the Sun—some 520 million km by end July—Rosetta needs to save energy for her final weeks.
"We need to maximise the power available to Rosetta's scientific instruments, and thus had no choice but to turn off the ESS," ESA senior science advisor Mark McCaughrean told AFP.
The ESS is the Electrical Support System on board Rosetta, used to send home the results of Philae's science experiments and status reports.
"The power will only dwindle further, and so now the focus turns fully to Rosetta, whose amazingly succesful scientific mission will come to an end on 30 September," said McCaughrean.
"Everyone involved will be extremely sad, of course, but equally enormously proud of what has been achieved by this unique space mission."
Scientists will be busy for years analysing the data sent back by Philae and Rosetta.
Comets are deemed to be balls of primitive dust and ice left from the early years of the Solar System.
Their makeup interests scientists who speculate that comets may have seeded Earth—possibly other planets as well—with the ingredients for life.

Severs Linke like a Hatmehit! Freedom.
Read more at:[url=][/url]

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This thread was improv at itz best!  Rosetta will situate well and tale tell the rest of this comet's tail...
How comets are born
July 28, 2016

[Image: howcometsare.jpg]
Evidence that Comet 67P/Churyumov-Gerasimenko is composed of ancient material preserved from the formation of the early Solar System and that came together under low speed. The evidence collected by Rosetta lies in the comet's structural properties, the gases detected leaving the nucleus, and observations of surface features. Credit: Centre: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0; Insets: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; Fornasier et al. (2015); ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S; Langevin et al. (2016)

Detailed analysis of data collected by Rosetta show that comets are the ancient leftovers of early Solar System formation, and not younger fragments resulting from subsequent collisions between other, larger bodies.

Understanding how and when objects like Comet 67P/Churyumov-Gerasimenko took shape is of utmost importance in determining how exactly they can be used to interpret the formation and early evolution of our Solar System.
A new study addressing this question led by Björn Davidsson of the Jet Propulsion Laboratory, California Institute of Technology in Pasadena (USA), has been published in Astronomy & Astrophysics.
If comets are primordial, then they could help reveal the properties of the solar nebula from which the Sun, planets and small bodies condensed 4.6 billion years ago, and the processes that transformed our planetary system into the architecture we see today.
The alternative hypothesis is that they are younger fragments resulting from collisions between older 'parent' bodies such as icy trans-Neptunian objects (TNOs). They would then provide insight into the interior of such larger bodies, the collisions that disrupted them, and the process of building new bodies from the remains of older ones.
"Either way, comets have been witness to important Solar System evolution events, and this is why we have made these detailed measurements with Rosetta – along with observations of other comets – to find out which scenario is more likely," says Matt Taylor, ESA's Rosetta project scientist.
During its two-year sojourn at Comet 67P/Churyumov-Gerasimenko, Rosetta has revealed a picture of the comet as a low-density, high-porosity, double-lobed body with extensive layering, suggesting that the lobes accumulated material over time before they merged.
The unusually high porosity of the interior of the nucleus provides the first indication that this growth cannot have been via violent collisions, as these would have compacted the fragile material. Structures and features on different size scales observed by Rosetta's cameras provide further information on how this growth may have taken place.
[Image: 1-howcometsare.jpg]
Rosetta navigation camera (NavCam) image taken on 22 March 2015 at 77.8 km from the centre of comet 67P/Churyumov-Gerasimenko. The image has been cropped and measures 6.0 km across; the resolution is about 6.6 m/pixel. Credit: European Space Agency
Earlier work showed that the head and body were originally separate objects, but the collision that merged them must have been at low speed in order not to destroy both of them. The fact that both parts have similar layering also tells us that they must have undergone similar evolutionary histories and that survival rates against catastrophic collision must have been high for a significant period of time.

Merging events may also have happened on smaller scales. For example, three spherical 'caps' have been identified in the Bastet region on the small comet lobe, and suggestions are that they are remnants of smaller cometesimals that are still partially preserved today.
At even smaller scales of just a few metres across, there are the so-called 'goosebumps' and 'clod' features, rough textures observed in numerous pits and exposed cliff walls in various locations on the comet.
While it is possible that this morphology might arise from fracturing alone, it is actually thought to represent an intrinsic 'lumpiness' of the comet's constituents. That is, these 'goosebumps' could be showing the typical size of the smallest cometesimals that accumulated and merged to build up the comet, made visible again today through erosion due to sunlight.
According to theory, the speeds at which cometesimals collide and merge change during the growth process, with a peak when the lumps have sizes of a few metres. For this reason, metre-sized structures are expected to be the most compact and resilient, and it is particularly interesting that the comet material appears lumpy on that particular size scale.
Further lines of evidence include spectral analysis of the comet's composition showing that the surface has experienced little or no in situ alteration by liquid water, and analysis of the gases ejected from sublimating ices buried deeper within the surface, which finds the comet to be rich in supervolatiles such as carbon monoxide, oxygen, nitrogen and argon.
These observations imply that comets formed in extremely cold conditions and did not experience significant thermal processing during most of their lifetimes. Instead, to explain the low temperatures, survival of certain ices and retention of supervolatiles, they must have accumulated slowly over a significant time period.
"While larger TNOs in the outer reaches of the Solar System appear to have been heated by short-lived radioactive substances, comets don't seem to show similar signs of thermal processing. We had to resolve this paradox by taking a detailed look at the time line of our current Solar System models, and consider new ideas," says Björn.

[Image: 2-howcometsare.jpg]

Two main theories exist for how comets are born. In both cases, 'pebbles' start assembling from debris in the solar nebula, reaching sizes of about 1 cm. Then, according to the collisional rubble pile theory (left column), large objects such as the trans-Neptunian objects (TNOs) formed rapidly, within the first one million year of the solar nebula, aided by turbulent gas streams and gravity that rapidly accelerated their growth to sizes of up to 400 km. These objects also underwent internal heating caused by the decay of radioactive substances, which resulted in their dense, low-porosity structure, and kept growing over the following 400 million years, some of them even reaching sizes of Pluto or Triton-sized objects. In this scenario, comets form from fragments created in collisions between TNOs in the outer Solar System, and therefore are relatively young. According to the primordial rubble pile theory (right), instead, comets took a different path. After the rapid initial growth phase of the TNOs, leftover grains and 'pebbles' of icy material in the cold, outer parts of the solar nebula started to come together at low speed, undergoing a gradual growth with no thermal processing to their interior and yielding comets roughly 5 km in size by the time gas has disappeared from the solar nebula. The larger TNOs played a further role in the evolution of comets: by 'stirring' the cometary orbits, additional material was accreted at somewhat higher speed over the next 25 million years, forming the outer layers of the comets. The stirring also made it possible for the few kilometre-sized objects in size to bump gently into each other, leading to the bi-lobed nature of some observed comets. In the second hypothesis, comets are ancient objects made out of debris left over from the main planet-building phase and which contain preserved remnants of the early solar nebula materials. Evidence collected by Rosetta strongly favours the primordial rubble pile hypothesis, namely that comets were built up slowly through low-speed accumulation of material into the shapes observed today. Credit: European Space Agency
Björn and colleagues propose that the larger members of the TNO population formed rapidly within the first one million years of the solar nebula, aided by turbulent gas streams that rapidly accelerated their growth to sizes of up to 400 km.
Around three million years into the Solar System's history, gas had disappeared from the solar nebula, only leaving solid material behind. Then, over a much longer period of around 400 million years, the already massive TNOs slowly accreted further material and underwent compaction into layers, their ices melting and refreezing, for example. Some TNOs even grew into Pluto or Triton-sized objects.
Comets took a different path. After the rapid initial growth phase of the TNOs, leftover grains and 'pebbles' of icy material in the cold, outer parts of the solar nebula started to come together at low velocity, yielding comets roughly 5 km in size by the time gas has disappeared from the solar nebula. The low speeds at which the material accumulated led to objects with fragile nuclei with high porosity and low density.
This slow growth also allowed comets to preserve some of the oldest, volatile-rich material from the solar nebula, since they were able to release the energy generated by radioactive decay inside them without heating up too much.
The larger TNOs played a further role in the evolution of comets. By 'stirring' the cometary orbits, additional material was accreted at somewhat higher speed over the next 25 million years, forming the outer layers of comets. The stirring also made it possible for the few kilometre-sized objects in size to bump gently into each other, leading to the bi-lobed nature of some observed comets.
"Comets do not appear to display the characteristics expected for collisional rubble piles, which result from the smash-up of large objects like TNOs. Rather, we think they grew gently in the shadow of the TNOs, surviving essentially undamaged for 4.6 billion years," concludes Björn.
"Our new model explains what we see in Rosetta's detailed observations of its comet, and what had been hinted at by previous comet flyby missions."
"Comets really are the treasure-troves of the Solar System," adds Matt.
"They give us unparalleled insight into the processes that were important in the planetary construction yard at these early times and how they relate to the Solar System architecture that we see today."
[Image: 1x1.gif] Explore further: Comet probe Rosetta detects the 'most wanted molecule'
More information: B. J. R. Davidsson et al. The primordial nucleus of comet 67P/Churyumov-Gerasimenko, Astronomy & Astrophysics (2016). DOI: 10.1051/0004-6361/201526968 
Journal reference: Astronomy & Astrophysics [Image: img-dot.gif] [Image: img-dot.gif]
Provided by: European Space Agency

Read more at:[/url]

Comet Lovejoy shows asymmetric behavior at perihelion

July 26, 2016 by Tomasz Nowakowski report

[Image: cometlovejoy.jpg]
Photograph of the comet C/2014 Q2 (Lovejoy) taken on Jan. 19, 2015, from Tucson, Arizona, using a Sky-Watcher 100mm APO telescope and SBIG STL-11000M camera. Credit: John Vermette
(—Indian astronomers have recently conducted spectrographic observations of long-period Comet Lovejoy to study its gas emission. They found that this comet showcases an asymmetric behavior at perihelion and an increase in the activity during the post-perihelion phase. The findings were detailed in a paper published July 22 on the arXiv pre-print server.

Comet Lovejoy, formally designated C/2014 Q2, is an Oort cloud comet, discovered by Terry Lovejoy in August 2014. Its perihelion was on January 30, 2015 at a heliocentric distance of 1.29 AU, offering astronomers an excellent opportunity to observe its activity—in particular, the emission of numerous organic molecules in gas.

The scientists, led by Kumar Venkataramani of the Physical Research Laboratory in Ahmedabad, India, utilized the LISA spectrograph to obtain spectra of the comet. LISA is a low-resolution, high luminosity spectrograph, designed for the spectroscopic study of faint and extended objects. The instrument is installed on the 0.5 m telescope at the Mount Abu Infra-Red Observatory (MIRO), Mount Abu, India.

The observation campaign lasted from January to May 2015. It covered the period during which the comet's heliocentric distance varied from 1.29 AU, just prior to perihelion, to around 2.05 AU post perihelion. The spectra obtained by the researchers show strong molecular emission bands of diatomic carbon, tricarbon, cyanide, amidogen, hydridocarbon and neutral oxygen.

"Various molecular emission lines like C2, C3, CN, NH2, CH, O were clearly seen in the comet spectrum throughout this range. The most prominent of them being the C2 molecule, which was quite dominant throughout the time that we have followed the comet. Apart from the C2 emission band, those of CN and C3 were also quite prominent," the scientist wrote in the paper.

When a cold icy body like the Comet Lovejoy passes by the sun near perihelion, its ices start sublimating, releasing a mixture of gas and dust, which form the coma. Studying these emissions is crucial for scientists as comets could hold the key to our understanding of the solar system's evolution and the origin of life in the universe. Therefore, the abundance of volatile material in comets is the target of many scientific studies that seek to reveal the secrets of planet formation and demonstrate the conditions that occurred when our solar system was born.

According to the study, the gas production rate increased after perihelion and exhibited a decreasing trend only after February 2015. The researchers also noted a simultaneous increase in gas and dust, indicating an increase in the overall activity of the comet after its perihelion passage.

"This kind of asymmetry has been seen in many comets. (…) Although we do not have data points at exactly the same distance for pre- and post-perihelion passages, we can, perhaps, say that this comet may have a large positive asymmetry," the paper reads.

The scientists concluded that this asymmetry suggests that there might be volatile material present beneath the surface of the comet. It is also possible that the surface of the comet's nucleus consists of layers of ice that have different vaporization rates.

However, as the team noted, more exhaustive study is required to confirm their conclusions.

[Image: 1x1.gif] Explore further: Australian amateur Terry Lovejoy discovers new comet

More information: Optical Spectroscopy of Comet C/2014 Q2 (Lovejoy) from MIRO, arXiv:1607.06682 [astro-ph.EP]

Spectra of comet C/2014 Q2 (Lovejoy) were taken with a low resolution spectrograph mounted on the 0.5 m telescope at the Mount Abu Infrared Observatory (MIRO), India during January to May 2015 covering the perihelion and post-perihelion periods. The spectra showed strong molecular emission bands (C2, C3 and CN) in January, close to perihelion. We have obtained the scale lengths for these molecules by fitting the Haser model to the observed column densities. The variation of gas production rates and production rate ratios with heliocentric distance were studied. The extent of the dust continuum using the Af-rho parameter and its variation with the heliocentric distance were also investigated. The comet is seen to become more active in the post-perihelion phase, thereby showing an asymmetric behaviour about the perihelion.

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Rosetta captures comet outburst
August 25, 2016

[Image: rosettacaptu.gif]
Rosetta’s OSIRIS wide-angle camera captured an outburst from the Atum region on Comet 67P/Churyumov–Gerasimenko’s large lobe on 19 February 2016. The images are separated by half an hour each, covering the period 08:40–12:10 GMT, and as such show the comet rotating. Brightening in an initially shadowed region is first seen in the 09:40 image, with significant increase in brightness in subsequent images before subsiding again. The structure of more defined streams of dust and gas is also visible in later images. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
In unprecedented observations made earlier this year, Rosetta unexpectedly captured a dramatic comet outburst that may have been triggered by a landslide.

Nine of Rosetta's instruments, including its cameras, dust collectors, and gas and plasma analysers, were monitoring the comet from about 35 km in a coordinated planned sequence when the outburst happened on 19 February.
"Over the last year, Rosetta has shown that although activity can be prolonged, when it comes to outbursts, the timing is highly unpredictable, so catching an event like this was pure luck," says Matt Taylor, ESA's Rosetta project scientist.
"By happy coincidence, we were pointing the majority of instruments at the comet at this time, and having these simultaneous measurements provides us with the most complete set of data on an outburst ever collected."
The data were sent to Earth only a few days after the outburst, but subsequent analysis has allowed a clear chain of events to be reconstructed, as described in a paper led by Eberhard Grün of the Max-Planck-Institute for Nuclear Physics, Heidelberg, accepted for publication in Monthly Notices of the Royal Astronomical Society.
A strong brightening of the comet's dusty coma was seen by the OSIRIS wide-angle camera at 09:40 GMT, developing in a region of the comet that was initially in shadow.
Over the next two hours, Rosetta recorded outburst signatures that exceeded background levels in some instruments by factors of up to a hundred. For example, between about 10:00–11:00 GMT, ALICE saw the ultraviolet brightness of the sunlight reflected by the nucleus and the emitted dust increase by a factor of six, while ROSINA and RPC detected a significant increase in gas and plasma, respectively, around the spacecraft, by a factor of 1.5–2.5.
[Image: rosettacaptu.jpg]
The majority of Rosetta’s instruments were on and pointing at Comet 67P/Churyumov–Gerasimenko at the time of the outburst on 19 February 2016, allowing a clear chain of events to be reconstructed. The graphic highlights some of the measurements from the cameras, dust collectors, and gas and plasma analysers, with each one recording a peak compared with background levels at various times during the outburst. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; all data from Grün et al (2016)
In addition, MIRO recorded a 30ºC rise in temperature of the surrounding gas.
Shortly after, Rosetta was blasted by dust: GIADA recorded a maximum hit count at around 11:15 GMT. Almost 200 particles were detected in the following three hours, compared with a typical rate of 3–10 collected on other days in the same month.
At the same time, OSIRIS narrow-angle camera images began registering dust grains emitted during the blast. Between 11:10 GMT and 11:40 GMT, a transition occurred from grains that were distant or slow enough to appear as points in the images, to those either close or fast enough to be captured as trails during the exposures.

In addition, the startrackers, which are used to navigate and help control Rosetta's attitude, measured an increase in light scattered from dust particles as a result of the outburst.
The startrackers are mounted at 90º to the side of the spacecraft that hosts the majority of science instruments, so they offered a unique insight into the 3-D structure and evolution of the outburst.
Astronomers on Earth also noted an increase in coma density in the days after the outburst.
By examining all of the available data, scientists believe they have identified the source of the outburst.
[Image: 1-rosettacaptu.jpg]
On 19 February 2016 Rosetta’s instruments detected an outburst event from Comet 67P/Churyumov–Gerasimenko. The source was traced back to a location in the Atum region, on the comet’s large lobe, as indicated in this image. The inset image was taken a few hours after the outburst by Rosetta’s NavCam and shows the approximate source location. The image at left was taken on 21 March 2015 and is shown for context, and so there are some differences in shadowing/illumination as a result of the images being acquired at very different times. Credit: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0
"From Rosetta's observations, we believe the outburst originated from a steep slope on the comet's large lobe, in the Atum region," says Eberhard.
The fact that the outburst started when this area just emerged from shadow suggests that thermal stresses in the surface material may have triggered a landslide that exposed fresh water ice to direct solar illumination. The ice then immediately turned to gas, dragging surrounding dust with it to produce the debris cloud seen by OSIRIS.
"Combining the evidence from the OSIRIS images with the long duration of the GIADA dust impact phase leads us to believe that the dust cone was very broad," says Eberhard.
"As a result, we think the outburst must have been triggered by a landslide at the surface, rather than a more focused jet bringing fresh material up from within the interior, for example."
"We'll continue to analyse the data not only to dig into the details of this particular event, but also to see if it can help us better understand the many other outbursts witnessed over the course of the mission," adds Matt.
"It's great to see the instrument teams working together on the important question of how cometary outbursts are triggered."
[Image: 1x1.gif] Explore further: Image: Rosetta selfie 16 km from comet
More information: "The 19 Feb. 2016 outburst of comet 67P/CG: A Rosetta multi-instrument study," by E. Grün et al is published in the Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/stw2088 
Journal reference: Monthly Notices of the Royal Astronomical Society

Read more at:[/url][url=]
Missing comet lander Philae spotted at last: LilD  ESA (Update 2)
September 5, 2016

[Image: missingcomet.jpg]
Rosetta's lander Philae has been identified in OSIRIS narrow-angle camera images taken on 2 September 2016 from a distance of 2.7 km. The image scale is about 5 cm/pixel. Philae's 1 m-wide body and two of its three legs can be seen extended from the body. The images also provide proof of Philae's orientation. A Rosetta Navigation Camera image taken on 16 April 2015 is shown at top right for context, with the approximate location of Philae on the small lobe of Comet Churyumov-Gerasimenko marked. Credit: Main image and lander inset: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; context: ESA/Rosetta/ NavCam – CC BY-SA IGO 3.0
Europe's Rosetta spacecraft has finally spotted its tiny lander Philae, thought to be lost forever, stuck in a ditch on the surface of a comet hurtling through space, ground controllers said Monday.

"THE SEARCH IS OVER! I've found @Philae2014!!" the European Space Agency (ESA) tweeted on behalf of Rosetta, orbiting comet 67P/Churyumov-Gerasimenko at some 682 million kilometres (424 million miles) from Earth.
The agency released a photo of the washing machine-sized robot lab on the comet's rough surface, one of its three legs thrust dramatically into the air.
This was the first sighting of Philae since its rough landing in November 2014.
The image was captured by Rosetta's OSIRIS narrow-angle camera on Friday and downloaded two days later—just weeks before the official end of the ground-breaking science mission to unravel the mysteries of life on Earth.
"With only a month left of the Rosetta mission, we are so happy to have finally imaged Philae and to see it in such amazing detail," Cecilia Tubiana of the OSIRIS camera team, the first person to see the images, said in a statement.
The Twitter page of Philae, its communications unit switched off in July, remained silent.
The 100-kilogramme (220-pound) probe touched down on comet 67P in November 2014, after a 10-year, 6.5 billion kilometre (four billion-mile) journey piggybacking on Rosetta.
[Image: missingcomet.png]
Close-up of the Philae lander, imaged by Rosetta's OSIRIS narrow-angle camera on 2 September 2016 from a distance of 2.7 km. The image scale is about 5 cm/pixel. Philae's 1 m-wide body and two of its three legs can be seen extended from the body. The images also provide proof of Philae's orientation. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Philae bounced several times after its harpoons failed to fire, and ended up in a ditch shadowed from the Sun's battery-replenishing rays.
Until now, nobody knew exactly where.
The final hour
The tiny lab managed to conduct 60 hours of experiments and send home data before running out of power and entering standby mode on November 15, 2014.
"We were beginning to think that Philae would remain lost forever. It is incredible that we have captured this at the final hour," said Rosetta mission manager Patrick Martin.
The photo was taken at a distance of 2.7 kilometres from the surface of the comet, which is speeding away from the Sun at nearly 15 kilometres per second.
Rosetta is drawing closer to the comet for its own swansong.
[Image: 1-missingcomet.png]
An OSIRIS narrow-angle camera image taken on 2 September 2016 from a distance of 2.7 km in which Philae was definitively identified. The image has been processed to adjust the dynamic range in order to see Philae while maintaining the details of the comet's surface. Philae is located at the far right of the image, just above centre. The image scale is about 5 cm/pixel. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
On September 30, Rosetta will crashland and join Philae on the surface—their eternal resting place.
After it touches down, communications with the craft will be severed once and for all, closing the historic mission.

The 1.3-billion-euro ($1.4-billion) project was conceived to unravel the secrets of comets—believed to be time capsules from the birth of the Solar System.
The comet-sniffing and -prodding exploits of Rosetta and Philae were closely followed around the world via cartoon recreations of the pioneering pair.
Philae, in particular, earned a loyal Twitter following.
In June 2015, as it drew closer to the Sun, some 30,000 people retweeted Philae's unexpected reawakening: "Hello Earth! Can you hear me?"
After eight intermittent communications with ground control, Philae fell forever silent in July 2015.
[Image: 1-missingcomet.jpg]
A number of Philae's features can be made out in this image taken by Rosetta's OSIRIS narrow-angle camera image on 2 September 2016. The images were taken from a distance of 2.7 km, and have a scale of about 5 cm/pixel. Philae's 1 m wide body and two of its three legs can be seen extended from the body. Several of the lander's instruments are also identified, including one of the CIVA panoramic imaging cameras, the SD2 drill and SESAME-DIM (Surface Electric Sounding and Acoustic Monitoring Experiment Dust Impact Monitor). Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
"Philae is at the foot of a cliff in an extremely rocky zone" of the comet, Rosetta project chief Philippe Gaudon of France's CNES space agency told AFP, after examining the picture.
It is now clear that after bouncing, Philae landed the wrong-way up, "with one foot well in the air and its antennas pointing... groundwards," he said.
That is why communicating with Philae had been so difficult.
"This wonderful news means that we now have the missing 'ground-truth' information needed to put Philae's three days of science into proper context, now that we know where that ground actually is," said Rosetta project scientist Matt Taylor.
[Image: 1x1.gif] Explore further: OSIRIS spots Philae drifting across the comet

Read more at:[/url]
Quote:“This wonderful news means that we now have the missing ‘ground-truth’ information needed to put Philae’s three days of science into proper context, now that we know where that ground actually is!” says Matt Taylor, ESA’s Rosetta project scientist.

They have not released Coordinates yet(if ever? Cry )

[Image: 23854144071_f2f6813419_o.jpg]

Where did Philae land/not land?

As itza askew thatz why EYE ask you?

Same game by any other name:
Rite where Rosetta will be left off on official offworld office on ice.

To re-join with her brother... Arrow All Ma'at @ that.


67 P was as bennu is anu.

improv re: Knews itza-self
Watching that orbit video, seems the orbiter making "UFO LIKE" maneuvers Holycowsmile

Bob... Ninja Alien2
The grandkid was over for a visit a few hours ago...

I told him they found Philae!

He can't wait for the next cartoons.

He knew philae was camping and fell space.

He knew his batteries were dead.
[Image: 1-missingcomet.jpg]
Know he knows they found him under a big rock stuck in some boulders sideways in the dark.   Angel

And that sister rosetta is gonna Arrow crash land and power-off too Angelic005 to join him.

That is gonna be a cool animated event. LilD
Rosetta catches dusty organics
September 8, 2016

[Image: rosettacatch.jpg]
Optical image of two of the dust grains collected and analysed by COSIMA, named Kenneth and Juliette, which show the signature of carbon-based organics. They were collected in May and October 2015 respectively. Credit: ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S/ Fray et al (2016)
Rosetta's dust-analysing COSIMA (COmetary Secondary Ion Mass Analyser) instrument has made the first unambiguous detection of solid organic matter in the dust particles ejected by Comet 67P/Churyumov-Gerasimenko, in the form of complex carbon-bearing molecules

Read more at:

While organics had already been detected in situ on the comet's surface by instruments on-board Philae and from orbit by Rosetta's ROSINA , those were both in the form of gases resulting from the sublimation of ices. By contrast, COSIMA has made its detections in solid dust.

Their presence was only ever hinted at in previous comet missions, which flew by their targets at high speed and, as a result, disrupted the particles, making characterisation challenging. But Rosetta is orbiting Comet 67P/C-G and can catch dust particles moving at low speed.

"Our analysis reveals carbon in a far more complex form than expected," remarked Hervé Cottin, one of the authors of the paper reporting the result that is published in Nature today. "It is so complex, we can't give it a proper formula or a name!"

The organic signatures of seven particles are presented in the paper, which the COSIMA team say are representative of the two hundred plus grains analysed so far.

The carbon is found to be mixed with other previously reported elements such as sodium, magnesium, aluminium, silicon, calcium and iron. It is bound in very large macromolecular compounds similar to the insoluble organic matter found in carbonaceous chondrite meteorites that have fallen to Earth, but with a major difference: there is much more hydrogen found in the comet's samples than in meteorites.

[Image: 1-rosettacatch.jpg]

Comparing the spectra determined by COSIMA for the dust particles Kenneth and Juliette with the composition of organic matter (Insoluble Organic Matter, IOM) in the Murchison chondritic meteorite. The detections of hydrogen (H), Sodium (Na), Silicon (Si) and Iron (Fe) are also indicated. The red spectra are measured on the cometary particles while the black ones are measured next to them, and are representative of the instrument itself. Credit: ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S/ Fray et al (2016)

But as this kind of meteorite is associated with reasonably well-processed parent bodies such as asteroids, it is reasonable to assume that they lost their hydrogen due to heating. By contrast, comets must have avoided such significant heating to retain their hydrogen, and therefore must contain more primitive material.

From analyses of meteorites and laboratory simulations, the team was also expecting to identify a wide diversity of organic material in Comet 67P/C-G, ranging from very small molecules to heavy (or 'high molecular weight') organics.

Although Rosetta's ROSINA and Philae's PTOLEMY and COSAC instruments detected numerous low-molecular weight volatile organic molecules, COSIMA only saw very large carbon-bearing macromolecules in the dust particles, with nothing in between. This suggests potentially different sources for the lightweight volatile and heavier refractory carbonaceous material detected in the comet.

"Although we cannot know if the organics seen in these dust particles were created in the interstellar medium before the protoplanetary nebula came together, or in the protoplanetary disk during early Solar System formation, COSIMA's dust grains are certainly witnesses to early formation processes, including that of the comet itself," says Nicolas Fray, first author of the paper.

"These particles have remained pristine and untouched for billions of years until they were released in the days or weeks before being 'caught' by COSIMA," adds Martin Hilchenbach, principal investigator of COSIMA. "The results add to the growing picture that Comet 67P/C-G contains some of the most primitive material from our Solar System's early history."

[Image: 1x1.gif] Explore further: Image: Rosetta selfie 16 km from comet

More information: Nicolas Fray et al. High-molecular-weight organic matter in the particles of comet 67P/Churyumov–Gerasimenko, Nature (2016). DOI: 10.1038/nature19320 

Journal reference: Nature [Image: img-dot.gif] [Image: img-dot.gif]
Provided by: European Space Agency

Read more at:[url=][/url]
Rosetta's descent towards region of active pits
September 9, 2016

Improv was as Impact Will be...?
All Ma'at @ That! LilD
[Image: rosettasdesc.jpg]
Rosetta is destined to make a controlled impact into the Ma'at region of Comet 67P/Churyumov–Gerasimenko on 30 September 2016, targeting a point within a 700 × 500 m ellipse (a very approximate outline is marked on the image). The target area is home to several active pits measuring over 100 m across and 60 m deep, from which a number of the comet's dust jets originate. Some of the pit walls also exhibit intriguing metre-sized lumpy structures called 'goosebumps', which could be the signatures of early cometesimals that agglomerated to create the comet in the early phases of Solar System formation. Rosetta's final descent may afford detailed close-up views of these features. Credit: ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
Squeezing out unique scientific observations until the very end, Rosetta's thrilling mission will culminate with a descent on 30 September towards a region of active pits on the comet's (Duck's) 'head'. youareaduck

The region, known as Ma'at, lies on the smaller of the two lobes of Comet 67P/Churyumov–Gerasimenko. It is home to several active pits more than 100 m in diameter and 50–60 m in depth – where a number of the comet's dust jets originate.
The walls of the pits also exhibit intriguing metre-sized lumpy structures called 'goosebumps', which scientists believe could be the signatures of early 'cometesimals' that assembled to create the comet in the early phases of Solar System formation.
Rosetta will get its closest look yet at these fascinating structures on 30 September: the spacecraft will target a point adjacent to a 130 m-wide, well-defined pit that the mission team has informally named Deir el-Medina, after a structure with a similar appearance in an ancient Egyptian town of the same name.
Like the archaeological artefacts found inside the Egyptian pit that tell historians about life in that town, the comet's pit contains clues to the geological history of the region.
Rosetta will target a point very close to Deir el-Medina, within an ellipse about 700 × 500 m.
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A simplified overview of Rosetta's last week of manoeuvres at Comet 67P/Churyumov–Gerasimenko (comet rotation is not considered). After 24 September the spacecraft will leave the flyover orbits and transfer towards an initial point of a 16×23 km orbit that will be used to prepare for the final descent. The collision course manoeuvre will take place in the evening of 29 September, initiating the descent from an altitude of about 20 km. The impact is expected to occur at 10:40 UTC (±20 minutes) at the comet, which taking into account the 40 minute signal travel time between Rosetta and Earth on 30 September, means the confirmation would be expected at mission control at 11:20 UTC / 13:20 CEST (±20 minutes). Credit: ESA
Since 9 August, Rosetta has been flying elliptical orbits that bring it progressively closer to the comet – on its closest flyby, it may come within 1 km of the surface, closer than ever before.
"Although we've been flying Rosetta around the comet for two years now, keeping it operating safely for the final weeks of the mission in the unpredictable environment of this comet and so far from the Sun and Earth, will be our biggest challenge yet," says Sylvain Lodiot, ESA's spacecraft operations manager.
"We are already feeling the difference in gravitational pull of the comet as we fly closer and closer: it is increasing the spacecraft's orbital period, which has to be corrected by small manoeuvres. But this is why we have these flyovers, stepping down in small increments to be robust against these issues when we make the final approach."
The final flyover will be complete on 24 September. Then a short series of manoeuvres needed to line Rosetta up with the target impact site will be executed over the following days as it transfers from flying elliptical orbits around the comet onto a trajectory that will eventually take it to the comet's surface on 30 September.

The collision manoeuvre will take place in the evening of 29 September, initiating the descent from an altitude of about 20 km. Rosetta will essentially free-fall slowly towards the comet in order to maximise the number of scientific measurements that can be collected and returned to Earth before its impact.
A number of Rosetta's scientific instruments will collect data during the descent, providing unique images and other data on the gas, dust and plasma very close to the comet. The exact complement of instruments and their operational timeline remains to be fixed, because it depends on constraints of the final planned trajectory and the data rate available on the day.
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Confirmation that Rosetta has ended its mission will be seen on screen in mission control on a 'spectrum analyser', a type of graph that shows the carrier signal received by the ground stations on Earth. Contrary to Rosetta's wake-up from deep space hibernation in January 2014, where a rise in the spacecraft carrier signal was seen in the on-screen spectrum analyser, mission controllers will see the signal drop for the final time once it ceases to transmit. The left-hand sketch here represents a typical signal received from the spacecraft, against the background noise. Once the spacecraft is no longer transmitting, then no signal will be seen in the spectrum analyser (right). Rosetta's collision with the surface is expected to occur at 10:40 UTC (±20 minutes) at the comet. Taking into account the 40 minute signal travel time between Rosetta and Earth on 30 September, this means the confirmation would be expected at mission control at 11:20 UTC / 13:20 CEST (±20 minutes). Credit: ESA
The impact is predicted to occur within 20 minutes of 10:40 UTC, with uncertainties linked to the exact trajectory of Rosetta on the day, and the influence of gravity close to the comet. Taking into account the additional 40 minute signal travel time between Rosetta and Earth on 30 September, this means that the confirmation of impact is expected at ESA's mission control in Darmstadt, Germany, within 20 minutes of 11:20 UTC (13:20 CEST). The times will be updated as the trajectory is refined.
Mirroring Rosetta's wake-up from deep space hibernation in January 2014, where a rising peak at the right frequency confirmed that the spacecraft was alive and transmitting its carrier signal, mission controllers will see that peak disappear for a final time once Rosetta impacts. It will not be possible to retrieve any data after this time.
"Last month we celebrated two thrilling years since arriving at the comet, and also a year since the comet's closest approach to the Sun along its orbit," says Matt Taylor, ESA's Rosetta project scientist.
"It's hard to believe that Rosetta's incredible 12.5 year odyssey is almost over, and we're planning the final set of science operations, but we are certainly looking forward to focusing on analysing the reams of data for many decades to come."
"This pioneering mission may be coming to an end, but it has certainly left its mark in the technical, scientific and public spheres as being one of outstanding success, with incredible achievements contributing to the current and future understanding of our Solar System," adds Patrick Martin, ESA's Rosetta mission manager.
[Image: 1x1.gif] Explore further: Image: Rosetta mission selfie at comet
Provided by: European Space Agency

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Impact? Sheep  Not Impact?
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In the three months centred around the comet's closest approach to the Sun, on 13 August 2015, Rosetta's cameras captured 34 outbursts.
These violent events were over and above regular jets and flows of material seen streaming from the comet's nucleus. The latter switch on and off with clockwork repeatability from one comet rotation to the next, synchronised with the rise and fall of the Sun's illumination.
By contrast, outbursts are much brighter than the usual jets – sudden, brief, high-speed releases of dust. They are typically seen only in a single image, indicating that they have a lifetime shorter than interval between images – typically 5–30 minutes.
A typical outburst is thought to release 60–260 tonnes of material in those few minutes.
On average, the outbursts around the closest approach to the Sun occurred once every 30 hours – about 2.4 comet rotations. Based on the appearance of the dust flow, they can be divided into three categories.
One type is associated with a long, narrow jet extending far from the nucleus, while the second involves a broad, wide base that expands more laterally. The third category is a complex hybrid of the other two.
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Guide to comet activity. Credit: OSIRIS: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; NavCam: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0
"As any given outburst is short-lived and only captured in one image, we can't tell whether it was imaged shortly after the outburst started, or later in the process," notes Jean-Baptiste Vincent, lead author of the paper published today in Monthly Notices of the Astronomical Society .
"As a result, we can't tell if these three types of plume 'shapes' correspond to different mechanisms, or just different stages of a single process.
"But if just one process is involved, then the logical evolutionary sequence is that an initially long narrow jet with dust is ejected at high speed, most likely from a confined space.
"Then, as the local surface around the exit point is modified, a larger fraction of fresh material is exposed, broadening the plume 'base'.
"Finally, when the source region has been altered so much as not to be able to support the narrow jet anymore, only a broad plume survives."
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Summer outburst sources. Credit: OSIRIS: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
[Image: 1x1.gif] Explore further: Image: Increasingly active Comet 67P
Provided by: European Space Agency

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This image from was terrible quality.

here is the ESA link and better quality
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and here is the link from ESA for the other image

Today Rosetta begins her final plunge to the comet for eternity...joining philae and powering down to silence.

Rosetta: beginning of the end for Europe's comet craft
September 29, 2016 by Mariëtte Le Roux

67P is a DUCK.

An artist's impression of the Rosetta orbiter at comet 67P/Churyumov–Gerasimenko on December 3, 2012
Europe was poised Thursday to crashland its Rosetta spacecraft on a comet it has stalked for over two years, joining robot lander Philae on the cosmic wanderer's icy surface in a final suicide mission.

A 12-year odyssey to probe the origins of our Solar System will conclude with a last-gasp spurt of science-gathering after Rosetta is instructed at 2050 GMT to quit the orbit of Comet 67P/Churyumov-Gerasimenko.
The space explorer will descend over a leisurely 14 hours, from an altitude of 19 kilometres (12-miles), sniffing the comet's gassy coma, or halo, measuring its temperature and gravity, and taking pictures from closer than ever before.
"It's all go," Rosetta project scientist Matt Taylor told AFP at the European Space Agency's mission control centre in Darmstadt.
"We're all very excited. In the final descent, we will get into a region that we have never sampled before. We've never been below two kilometres, and that region is where the coma, the comet atmosphere, becomes alive, it's where it goes from being an ice to a gas."
Rosetta will receive the command to crash at a distance of 720 million kilometres (450 million miles) from Earth, with the comet zipping through space at a speed of over 14 kilometres (nine miles) per second.
A "controlled impact" at human walking speed, about 90 cm (35 inches) per second, is scheduled for 1040 GMT on Friday—give or take 20 minutes.
Confirmation of the mission's end is expected in Darmstadt some 40 minutes later, when Rosetta's delayed signal vanishes from ground controllers' computer screens.
"It's mixed emotions," Taylor said of the impending end.
While it will all be over for mission controllers, scientists will be analysing the information gleaned for "years if not decades" to come.
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An artist's impression of the Rosetta orbiter at comet 67P/Churyumov–Gerasimenko on December 3, 2012
Puzzle pieces
"We've only just started to get an understanding of what the data is telling us, putting together the pieces of the puzzle," said Taylor.
"We've got this massive puzzle, all the pieces are everywhere, and we need to put them together."
The first-ever mission to orbit and land on a comet was approved in 1993 to explore the origins and evolution of our Solar System—of which comets are thought to contain primordial material preserved in a dark space deep freeze.
Rosetta and lander probe Philae travelled more than six billion kilometres (3.7 billion miles) over 10 years to reach 67P in August 2014.

Philae was launched to the comet surface in November of that year, bouncing several times, then gathering 60 hours of on-site data which it sent home before entering standby mode.
Insights gleaned from the 1.4-billion-euro ($1.5-billion) mission have shown that comets crashing into an early Earth may well have brought amino acids, the building blocks of life.
Comets of 67P's type, however, certainly did not bring water, scientists have concluded.
Rosetta's comet is currently speeding away from the Sun on its near seven-year elongated orbit, which means the craft's solar panels are catching fewer battery-replenishing rays.
Rather than just letting it fade away, scientists opted to end the mission on a high by taking measures from distances too close to risk under usual operating conditions.
Rosetta was never designed to land.
"Tonight is the beginning of the end," said Taylor. "That is what we're waiting for—we're waiting for this manoeuvre to begin that final phase."
A highlight of the final hours will be a one-off chance to peer into mysterious pits dotting the landscape for hints as to what the comet's interior might look like.
Rosetta was programmed to switch off on impact, to make sure its signals do not interfere with any future space missions.
"After Rosetta has touched down, it will not be possible to collect or return any additional data," the ESA said.
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A photo released by the European Space Agency (ESA) in November 2014 shows an image taken by Rosetta's lander Philae on the surface of Comet 67P/Churyumov-Gerasimenko
Rosetta: What did Europe's comet mission uncover?
Europe's Rosetta spacecraft, due to switch off Friday after a 12-year odyssey, carried eleven scientific instruments to sniff and photograph a comet from all angles.
After arriving in orbit around comet 67P/Churyumov-Gerasimenko, it launched Philae, a separate lander, which itself had 10 hi-tech gadgets, including cameras, X-ray scans, radio wave probes and a drill that never deployed.
Together, the robot explorers have advanced our understanding of comets—of which there are billions—believed to be leftovers from the birth of our Solar System some 4.6 billion years ago.
"Nobody had any idea comets can be so weird until Rosetta got there," said Fabio Favata of the European Space Agency's (ESA) robotic exploration directorate.
What the mission found:


Quote:Expecting to encounter something roughly the shape of an American football, scientists were flabbergasted to observe through Rosetta's cameras that 67P resembled a rubber bath duck with a distinct "body" and "head", and a crack through its "neck".

Some scientists have since postulated that this shape was not created by erosion, but a low-velocity impact billions of years ago between two objects which fused.
This all suggests the comet was formed in a young, outer part of our Solar System that was much less densely packed with bodies than previously thought.
If not, 67P "is so fragile it should have been clobbered by something else and broken apart," ESA senior science advisor Mark McCaughrean told AFP.
This affects our understanding of planetary formation, thought to have happened when ice and dust debris, swirling around in a proto-planetary disk around an infant Sun, collided and stuck together, growing bigger and bigger over time.
...but hard
The comet's surface was another surprise.
It was less "fluffy" and much harder than expected, which contributed to Philae bouncing several times after its harpoons failed to fire on landing.
The comet had much less water ice than thought, was littered with pebbles and rocks ranging in size from a few centimetres (inches) across to five metres (18 feet), and pocked with deep craters. The surface is rendered super-dark and non-reflective by a thin layer of dust.
Scientists were astonished to find oxygen molecules in the gassy halo around the comet, and said they appeared to be older than our Solar System.
Scientific models had previously calculated that oxygen as a molecular compound on its own would not have existed at the time the comet was formed, as it would have bonded with other elements like hydrogen.
So, how the comet got its oxygen remains a mystery.
Life's beginnings
67P has organic molecules, many different ones—including amino acids, which are the building blocks of life as we know it.
This discovery supports the hypothesis that comets may very well have helped spark life on Earth by delivering organic materials when they slammed into a young planet that was basically molten iron.
No H2O
Water, on the other hand, is unlikely to have come from comets of 67P's type, the mission found.
The water on Rosetta is of a very different "flavour" than that on our planet, with three times more deuterium, a heavy hydrogen isotope.
Analysing the comet's chemical signature, Rosetta scientists concluded it probably smells like a noxious mix of rotten eggs, horse urine, alcohol and bitter almonds.
"If you could smell the comet, you would probably wish that you hadn't," the ESA team said at the time.
No attraction
Philae's magnetometer found that, surprisingly, 67P has no measurable magnetic field—throwing into question another key theory on the formation of solar system bodies.
It implied that magnetism played no part in debris in the early Solar System clumping together to form planets, comets, asteroids and moons.
Not over yet
Scientists expect that the data extracted by Philae and Rosetta will keep them busy for decades to come.
"The metaphor I used at the beginning, was Rosetta would be the key that would unlock the treasure chest to the secrets of the Solar System. I think... we found the key, it's on the floor and it's in pieces. We need to assemble the key first before we can unlock the treasure chest," said McCaughrean.
Rosetta: Comet mission with an Egyptian flavour
When Europe's comet chaser was launched in 2004, it boasted the name of the famous Rosetta stone, which had helped decipher hieroglyphics, the mysterious written language of the ancient Egyptians.
The moniker was chosen because Rosetta, the spacecraft, would also be a decoder—unravelling the mysteries of comets, which are clusters of ice and dust left over from the formation of the Solar System some 4.6 billion years ago.
Scientists believe comets shed light on how life on Earth came about.
In more than two years orbiting Comet 67P/Churyumov-Gerasimenko, which included placing the first ever lander on a comet surface, Rosetta has lived up to its cryptographer epithet, though many more secrets remain to be teased from the data unearthed.
The name also set the trend for naming aspects of the mission after Egyptian place names, gods or kings.
Here are some other names:
The site on the comet where Rosetta's Philae lander was meant to touch down in November 2014. The spot was named for an island on the Nile which became the new home of Pharaonic temples transferred from Philae, another island, when the Aswan Dam threatened to flood the complex.
The lander Philae bounced several times when its harpoons failed to fire, and instead of Agilkia, settled in a dark crevice in a different location, later named ABYDOS after an ancient Egyptian city.
A "pit" on the comet surface near the spot where Rosetta is to make a "controlled impact" on Friday.
According to the European Space Agency, the feature resembles a pit in an Egyptian town that was home to workers building pharaonic tombs in the Valley of the Kings. It became a dumping ground for discarded pottery with inscriptions recording aspects of daily life.
Just as the clay shards yielded insight into working class ancient Egyptians, so scientists hope that peering deep into Deir el-Medina as Rosetta descends will reveal the insides of a comet.
The "neck" that divides the two lobes of the plastic bath duck-shaped comet into a distinct "head" and larger "body".
"Hapi is the Nile god, and we figured that he should separate the lobes in the same way that the Nile splits Egypt into the eastern and western side," explains the European Space Agency's Rosetta blog.
A region on the larger comet lobes, Imhotep shares the name of a master architect and pyramid-builder who lived about 5,000 years ago and was deified after his death.
The other 18 comet regions are also named after Egyptian deities, including Aten, Aker, Ash (god of oases), Babi (god of virility), and Seth (god of the desert).
"We wanted to adhere to the ancient Egyptian theme of the mission," the ESA blog states. "Luckily, ancient Egyptians had so many deities in their long history that made this an easy decision.
"Moreover, many of the names were catchy, easy to remember—and more importantly, easy to pronounce."
An acronym for Optical, Spectroscopic and Infrared Remote Imaging System, the camera onboard Rosetta, Osiris was also the name of the ancient Egyptian god of the underworld.
The washing machine-sized comet lander got its name from the Nile island in southern Egypt where in 1815 an obelisk was found which was key to understanding the Rosetta stone, discovered in 1799, with carved inscriptions in hieroglyphs and Greek.
A gas "sniffer" onboard the Philae lander shares a name with an Egyptian king whose name appeared on the Rosetta stone.
The comet itself is named after the two Ukrainian astronomers, Klim Churyumov and Svetlana Gerasimenko, credited with discovering it in 1969. "P" refers to a periodic comet, which takes fewer than 200 years to orbit the Sun, while "67" is its number on a list of similar comets discovered.
[Image: 1x1.gif] Explore further: Rosetta: What did Europe's comet mission uncover?

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Rosetta measures production of water at comet over two years
September 29, 2016

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Comet 67P/C-G on 11 September 2015 - NavCam. Credit: ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
Over the past two years, Rosetta has kept a close eye on many properties of Comet 67P/Churyumov-Gerasimenko, tracking how these changed along the comet's orbit. A very crucial aspect concerns how much water vapour a comet releases into space, and how the water production rate varies at different distances from the Sun. For the first time, Rosetta enabled scientists to monitor this quantity and its evolution in situ over two years.

In a new study led by Kenneth C. Hansen of the University of Michigan, in the US, measurements of water production rate based on data from ROSINA, the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis, are compared with water measurements from other Rosetta instruments.
The combination of all instruments shows an overall increase of the production of water, from a few tens of thousands of kg per day when Rosetta first reached the comet, in August 2014, to almost 100 000 000 kg per day around perihelion, the closest point to the Sun along the comet's orbit, in August 2015. In addition, ROSINA data show that the peak in water production is followed by a rather steep decrease in the months following perihelion.
"We were pleasantly surprised to find such a good agreement between the data collected by all the various instruments in this unprecedented study of the water production rate's evolution for a Jupiter-family comet," says Hansen.
The scientists analysed almost two years' worth of data from ROSINA, which detects neutral water molecules with its Double-Focussing Mass Spectrometer (DFMS).
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Water production rate measured by different instruments at Comet 67P/C-G. Credit: Hansen et al. (2016)
"This is by no means trivial: ROSINA performs measurements locally, at specific points around the comet, and we need a model to extend them to the entire atmosphere," adds Hansen.
The simplest model would be a spherical distribution of the outgassing centred around the nucleus but, given the complex shape and season cycle of Comet 67P/C-G, this would be a very crude approximation. For this reason, the ROSINA team developed a series of numerical simulations to accurately describe the comet's production of water, which are presented in a separate study led by Nicolas Fougere also of the University of Michigan.
From these simulations, which showed that the water production rate at a comet like 67P/C-G is highly inhomogeneous, Hansen and his colleagues derived an empirical model, which they then used to transform the local ROSINA measurements into estimates of the overall water production rate.
The results revealed that, during the first several months of observations, when the comet was at distances between 3.5 and 1.7 astronomical units (au) from the Sun, water was predominantly produced in the comet's northern hemisphere.

Then, in May 2015, the equinox marked the end of the 5.5-year long northern summer and the beginning of the short and intense southern summer. At that time, the comet was about 1.7 au from the Sun, and scientists expected that the peak of water production would drift slowly from the northern to the southern hemisphere; instead, this transition happened more abruptly than predicted. This was likely due to the complex shape of the nucleus, which causes highly variable illumination conditions including self-shadowing effects.
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Simulation of comet 67P's water production rate during northern summer. Images adapted from Hansen et al. (2016). Credit: K.C. Hansen
As expected, the production of water peaked between the end of August and early September 2015, about three weeks after the comet's perihelion, which took place on 13 August, 1.24 au from the Sun. The data hint at possible variations in the water production rate at this epoch: these might be due to the spacecraft's motion relative to the comet, but could also be an indication of actual changes to the outgassing dynamics, and will be subject of future in-depth investigation.
In addition to the ROSINA measurements, Hansen and his colleagues collated a series of previously published measurements of the water production rate at 67P/C-G. These include observations performed with the Microwave Instrument for the Rosetta Orbiter (MIRO) shortly before and after Rosetta had reached the comet, data from the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) obtained between November 2014 and January 2015, and measurements from the Ion Composition Analyser, part of the Rosetta Plasma Consortium (RPC) suite of instruments, obtained between October 2014 and April 2015.
RPC-ICA does not detect water directly, but rather measures the ratio of differently ionised Helium ions; since He+ ions arise mainly from collisions between alpha particles (He2+) from the solar wind and neutral molecules, such as water, found in the comet's atmosphere, this ratio can be used to estimate the amount of water produced at the comet.
Hansen and his collaborators have found some small discrepancies between the various data sets: for example, the measurements from ROSINA yield systematically higher values than those from VIRTIS. One possible reason for this is the different nature of the two experiments: ROSINA samples the gas in the coma at the spacecraft's position, while VIRTIS tends to observe closer to the nucleus, where the water production activity is potentially more confined than it is further out in the coma. The difference in measurements techniques and the discrepancy could potentially indicate an extended source of water in the coma itself, for example icy grains that are lifted into the coma and turn into gas a few kilometers above the surface.
Another difference was found between the MIRO measurements, which indicate a rising trend in the water production rate from June to September 2014, and the first months of ROSINA data, starting in August, pointing to an almost constant rate in the same period.
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Simulation of comet 67P's water production rate around perihelion. Images adapted from Hansen et al. (2016). Credit: K.C. Hansen
"This could be explained if a sudden surge in the water production happened around the time of the first MIRO measurement, a few weeks before Rosetta's rendezvous with 67P/C-G, and the beginning of ROSINA observations," says Hansen.
The scientists also compared the comet's production rate of water to that of dust, which can be measured via ground-based observations and was recently reported in a study led by Colin Snodgrass of the Open University, UK. These observations were performed with a number of robotic telescopes across the globe, from Chile to Hawaii and the Canary Islands.
"The correlation between the production rate of water and dust, both before and after perihelion, is impressive, suggesting that the gas-to-dust ratio remained constant over this long period," explains Hansen.
Based on the water production rate, the team estimated that the comet lost some 6.4 billion kg of water to space over the period monitored by Rosetta, with the most intense mass loss happening near perihelion. The total mass loss, taking into account other gas molecules and in particular the dust, could be roughly 10 times larger than that and, if distributed uniformly across the comet nucleus, it would translate into a reduction of 2 to 4 metres.
"This study shows how cross comparison between different instruments and simulations is beginning to reveal the comet further," says Matt Taylor, Rosetta project scientist at ESA.
"Connecting in-situ measurements from Rosetta with ground-based observations was a major science goal for the mission and it is wonderful to see this cooperation in action," concludes Kathrin Altwegg, ROSINA principal investigator.
[Image: 1x1.gif] Explore further: Video: Rosetta's journey around Comet 67P/Churyumov–Gerasimenko
More information: Kenneth C. Hansen et al. Evolution of water production of 67P/Churyumov-Gerasimenko: An empirical model and a m[Image: img-dot.gif]ulti-instrument study, Monthly Notices of the Royal Astronomical Society (2016). DOI: 10.1093/mnras/stw2413 

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Itza Sang Real.


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Tomorrow the craft ends.
I would just love to see into the shadows on both sides.
The far right and lower right side shadow formation is very interesting too. 
Hopefully Keith will develop more gigapans of the comet.
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Mission complete—Rosetta's journey ends in daring descent to comet
September 30, 2016

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Sequence of images captured by Rosetta during its descent to the surface of Comet 67P/C-G on 30 September. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
ESA's historic Rosetta mission has concluded as planned, with the controlled impact onto the comet it had been investigating for more than two years.

Confirmation of the end of the mission arrived at ESA's control centre in Darmstadt, Germany at 11:19 GMT (13:19 CEST) with the loss of Rosetta's signal upon impact.
Rosetta carried out its final manoeuvre last night at 20:50 GMT (22:50 CEST), setting it on a collision course with the comet from an altitude of about 19 km. Rosetta had targeted a region on the small lobe of Comet 67P/Churyumov–Gerasimenko, close to a region of active pits in the Ma'at region.
The descent gave Rosetta the opportunity to study the comet's gas, dust and plasma environment very close to its surface, as well as take very high-resolution images.
Pits are of particular interest because they play an important role in the comet's activity. They also provide a unique window into its internal building blocks.
The information collected on the descent to this fascinating region was returned to Earth before the impact. It is now no longer possible to communicate with the spacecraft.
"Rosetta has entered the history books once again," says Johann-Dietrich Wörner, ESA's Director General. "Today we celebrate the success of a game-changing mission, one that has surpassed all our dreams and expectations, and one that continues ESA's legacy of 'firsts' at comets."
"Thanks to a huge international, decades-long endeavour, we have achieved our mission to take a world-class science laboratory to a comet to study its evolution over time, something that no other comet-chasing mission has attempted," notes Alvaro Giménez, ESA's Director of Science.

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Animation of Rosetta’s final trajectory in the last 10 days of its mission at Comet 67P/Churyumov–Gerasimenko. Credit: ESA
"Rosetta was on the drawing board even before ESA's first deep-space mission, Giotto, had taken the first image of a comet nucleus as it flew past Halley in 1986.
"The mission has spanned entire careers, and the data returned will keep generations of scientist busy for decades to come."
"As well as being a scientific and technical triumph, the amazing journey of Rosetta and its lander Philae also captured the world's imagination, engaging new audiences far beyond the science community. It has been exciting to have everyone along for the ride," adds Mark McCaughrean, ESA's senior science advisor.

Since launch in 2004, Rosetta is now in its sixth orbit around the Sun. Its nearly 8 billion-kilometre journey included three Earth flybys and one at Mars, and two asteroid encounters.
The craft endured 31 months in deep-space hibernation on the most distant leg of its journey, before waking up in January 2014 and finally arriving at the comet in August 2014.
After becoming the first spacecraft to orbit a comet, and the first to deploy a lander, Philae, in November 2014, Rosetta continued to monitor the comet's evolution during their closest approach to the Sun and beyond.
"We've operated in the harsh environment of the comet for 786 days, made a number of dramatic flybys close to its surface, survived several unexpected outbursts from the comet, and recovered from two spacecraft 'safe modes'," says operations manager Sylvain Lodiot.
"The operations in this final phase have challenged us more than ever before, but it's a fitting end to Rosetta's incredible adventure to follow its lander down to the comet."
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Rosetta's last image of Comet 67P/Churyumov-Gerasimenko, taken shortly before impact, at an estimated altitude of 51 m above the surface. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
The decision to end the mission on the surface is a result of Rosetta and the comet heading out beyond the orbit of Jupiter again. Further from the Sun than Rosetta has ever journeyed before, there would be little power to operate the craft.
Mission operators were also faced with an imminent month-long period when the Sun is close to the line-of-sight between Earth and Rosetta, meaning communications with the craft would have become increasingly more difficult.
"With the decision to take Rosetta down to the comet's surface, we boosted the scientific return of the mission through this last, once-in-a-lifetime operation," says mission manager Patrick Martin.
Many surprising discoveries have already been made during the mission, not least the curious shape of the comet that became apparent during Rosetta's approach in July and August 2014. Scientists now believe that the comet's two lobes formed independently, joining in a low-speed collision in the early days of the Solar System.
Long-term monitoring has also shown just how important the comet's shape is in influencing its seasons, in moving dust across its surface, and in explaining the variations measured in the density and composition of the coma, the comet's 'atmosphere'.
Some of the most unexpected and important results are linked to the gases streaming from the comet's nucleus, including the discovery of molecular oxygen and nitrogen, and water with a different 'flavour' to that in Earth's oceans.
Together, these results point to the comet being born in a very cold region of the protoplanetary nebula when the Solar System was still forming more than 4.5 billion years ago.
While it seems that the impact of comets like Rosetta's may not have delivered as much of Earth's water as previously thought, another much anticipated question was whether they could have brought ingredients regarded as crucial for the origin of life.
[Image: 2-missioncompl.jpg]
Rosetta’s planned impact point in Ma’at shown in context with Philae’s first and final touchdown sites. All three sites are on the smaller of Comet 67P/Churyumov–Gerasimenko’s two lobes. Credit: CIVA: ESA/Rosetta/Philae/CIVA; NAVCAM: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0; OSIRIS: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; ROLIS: ESA/Rosetta/Philae/ROLIS/DLR
Rosetta did not disappoint, detecting the amino acid glycine, which is commonly found in proteins, and phosphorus, a key component of DNA and cell membranes. Numerous organic compounds were also detected ¬by Rosetta from orbit, and also by Philae in situ on the surface.
"It's a bittersweet ending, but in the end the mechanics of the Solar System were simply against us: Rosetta's destiny was set a long time ago. But its superb achievements will now remain for posterity and be used by the next generation of young scientists and engineers around the world."
While the operational side of the mission has finished today, the science analysis will continue for many years to come.
Overall, the results delivered by Rosetta so far paint comets as ancient leftovers of early Solar System formation, rather than fragments of collisions between larger bodies later on, giving an unparalleled insight into what the building blocks of the planets may have looked like 4.6 billion years ago.
"Just as the Rosetta Stone after which this mission was named was pivotal in understanding ancient language and history, the vast treasure trove of Rosetta spacecraft data is changing our view on how comets and the Solar System formed," says project scientist Matt Taylor.
"Inevitably, we now have new mysteries to solve. The comet hasn't given up all of its secrets yet, and there are sure to be many surprises hidden in this incredible archive. So don't go anywhere yet – we're only just beginning."
Rosetta was an ESA mission with contributions from its Member States and NASA. Rosetta's Philae lander was provided by a consortium led by DLR, MPS, CNES and ASI. Rosetta was the first mission in history to rendezvous with a comet and escort it as they orbited the Sun together. It was also the first to deploy a lander to a comet's surface, and later end its mission in a controlled impact on the comet.
Comets are time capsules containing primitive material left over from the epoch when the Sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, via both remote and in situ observations, the Rosetta mission is a key to unlocking the history and evolution of our Solar System.
[Image: 1x1.gif] Explore further: Europe's comet chaser Rosetta concludes 12-year-mission
Provided by: European Space Agency

Read more at:[/url][url=]
And that is exactly what the Ceres team should have done with Dawn,
sending it right smack dab into the crater below the LM.
It would have been a piece of cake for the NASA boys to do that and capture awesome images.
Ceres Dawn
Mission Incomplete
NASA Incompetence

Aside from that, how absolutely precious would images of the Rosetta crash site be?
Quote:Aside from that, how absolutely precious would images of the Rosetta crash site be?

Well at least we can gain a context from another imager ... consolation prize Cry

Kepler gets the 'big picture' of comet 67P
October 7, 2016 by Michele Johnson

[Image: keplergetsth.gif]
Credit: The Open University/C. Snodgrass and SETI Institute/E. Ryan

On Sept. 30, the European Space Agency concluded its Rosetta mission and the study of comet 67P/Churyumov–Gerasimenko. During the final month of the mission, NASA's planet-hunting Kepler spacecraft had a unique opportunity to provide a 'big picture' view of the comet as it was unobservable from Earth: Ground-based telescopes could not see comet 67P, because the comet's orbit placed it in the sky during daylight hours.

From Sept. 7 through Sept. 20, the Kepler spacecraft, operating in its K2 mission, fixed its gaze on comet 67P. From the distant vantage point of Kepler, the spacecraft could observe the comet's core and tail. The long-range global view of Kepler complements the close-in view of the Rosetta spacecraft, providing context for the high-resolution investigation Rosetta performed as it descended closer and closer to the comet.
During the two-week period of study, Kepler took a picture of the comet every 30 minutes. The animation shows a period of 29.5 hours of observation from Sept. 17 through Sept. 18. The comet is seen passing through Kepler's field of view from top right to bottom left, as outlined by the diagonal strip. The white dots represent stars and other regions in space studied during K2's tenth observing campaign.
As a comet travels through space it sheds a tail of gas and dust. A comet's activity level can be obtained by measuring the reflected sunlight. Analyzing the Kepler data, scientists will be able to determine the amount of mass lost each day as comet 67P travels through the solar system.
[Image: 1x1.gif] Explore further: Final descent image from Rosetta spacecraft
Provided by: NASA

Read more at:[url=][/url]
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Comet dust under the microscope
October 10, 2016

[Image: cometdustund.jpg]
Comet Tschuri on January 17, 2016. Dust particles will provide valuable information about our solar system. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Comet dust from the Rosetta mission is providing insights into the origins of our solar system. A research project focusing on the dust, which is supported by the Austrian Science Fund FWF and being carried at the Space Research Institute (IWF) of the Austrian Academy of Sciences, has direct access to data from a high resolution atomic force microscope on board the Rosetta orbiter.

The European Space Agency's (ESA) Rosetta mission to comet 67P/Churyumov–Gerasimenko ("Tchouri") has caused quite a stir. A project funded by the Austrian Science Fund FWF is now working on the analysis of this dust. The project leader, British scientist Mark Bentley, Principal Investigator of the MIDAS instrument on board the Rosetta, has just published the initial findings of the research in the journal Nature.
A scientific treasure chest
MIDAS, the Micro-Imaging Dust Analysis System, is a special microscope on board the Rosetta orbiter, designed, built and operated by a consortium led by IWF Graz. The instrument collects dust from the comet's surroundings and analyses it. Mark Bentley firmly believes that the analysis of the comet dust will prove to be a scientific treasure chest: "Comets are among the earliest bodies of our solar system. They have survived its billions of years of evolution almost unchanged, and they can provide information about the origin of the Sun and planets." And this is precisely what is being investigated using the data collected by MIDAS.


Credit: Austrian Science Fund (FWF)
Cutting-edge technology
MIDAS is a specially constructed atomic force microscope that enables the analysis of dust particles at a resolution of just a few nanometres. To attain this high resolution, an extremely fine needle scans the surface of an object and the deflection of the tip by the surface structure is measured. "MIDAS allows us to create three-dimensional images of the grains of comet dust. This is crucially important for our project," says Mark Bentley, explaining another aspect of the measuring method.
Multifaceted dust
Like the dust he is analysing, the aims of Bentley's research are multifaceted. He wants to determine the shape and size of different comet dust particles, analyse their surface structures, and identify the sub-grains, from which the particles are formed. As Bentley explains, thanks to the use of an additional operating mode provided by MIDAS, he will be able to extend the range of his tests even further: "We can also use MIDAS to measure magnetism. This will enable us to measure the magnetic material in the comet dust, which will tell us a lot about possible magnetic fields in the early solar system."
[Image: cometdustund.png]
“Mountain ranges” on microscopic particles of comet dust are now analysed in great detail. Credit: ESA/Rosetta/IWF for the MIDAS team IWF/ESA/LATMOS/Universiteit Leiden/Universität Wien
Slow science

The Rosetta mission offers a particularly crucial advantage for Bentley's research: relative to the comet, the probe moves at a snail's pace. This means that the dust can be collected gently and without being damaged. Bentley explains: "Earlier missions flew by various comets at a very high speed. This resulted in the particles being damaged during collection, so they were no longer in their original state. This is not the case with Rosetta." The dust is collected from the comet coma, the mixture of dust and gas that surrounds the comet. The careful collection method combined with the very high resolution offered by MIDAS also enables tests to be carried out on the size distribution of dust particles in the coma, on fragmentation mechanisms, and on temporal and seasonal changes in the dust particles.
Special powers
Thanks to the successful "couple's dance" between 67P and the Rosetta probe, which has been under way for some time now, it has already been possible to collect sufficient dust to carry out highly informative qualitative and quantitative analyses. MIDAS has already elicited considerable volumes of data from the dust. Bentley also had another scientific ace up his sleeve: Because he was responsible for operating MIDAS, he not only had direct access to the very latest data from space, he could also have targeted measurements of the dust particles carried out, which furthered his research. As a result, this FWF project will make an important contribution to the understanding of our solar system.
[Image: 1x1.gif] Explore further: Rosetta collects and examines space dust samples from comet 67P
More information: Mark S. Bentley et al. Aggregate dust particles at comet 67P/Churyumov–Gerasimenko, Nature (2016). DOI: 10.1038/nature19091
Mark Stephen Bentley et al. MIDAS: Lessons learned from the first spaceborne atomic force microscope, Acta Astronautica (2016). DOI: 10.1016/j.actaastro.2016.01.012
Physical properties of dust particles in cometary comae: from clues to evidence with the Rosetta mission.
The Micro Imaging and Dust Analysis System – New Possibilities for Space Sciences.
The nature of (sub-)micrometre cometary dust particles detected with MIDAS.
Cometary dust at the nanometre scale – the MIDAS view after perihelion.
Cometary dust at the smallest scale – latest results of the MIDAS Atomic Force Microscope onboard Rosetta. 
Journal reference: Nature [Image: img-dot.gif] [Image: img-dot.gif] Acta Astronautica [Image: img-dot.gif] [Image: img-dot.gif]
Provided by: Austrian Science Fund (FWF)

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Astronomers predict possible birthplace of Rosetta comet
October 20, 2016

[Image: astronomersp.jpg]
Credit: University of Western Ontario
When the Rosetta spacecraft successfully touched down on comet 67P/Churyumov-Gerasimenko on Sept. 30, the news was shared globally via Twitter in dozens of languages. Citizens the world over were engaged by the astronomical achievement, and now the European Space Agency and NASA are eager to learn as much as possible about the critically important celestial body of ice.

Using statistical analysis and scientific computing, Western astronomers have charted a path that most likely pinpoints the very origins of comet 67P/Churyumov-Gerasimenko, which is vital information in discovering what kind of material it is made from and just how long it has been present in our solar system.
Mattia Galiazzo, a postdoctoral scholar in the Department of Physics & Astronomy, presented his findings this week at the joint 48th annual meeting of the Division for Planetary Sciences of the American Astronomical Society and 11th annual European Planetary Science Congress in Pasadena, Calif. Galiazzo collaborated on the findings with solar system expert Paul Wiegert from Western's Centre for Planetary Science & Space Exploration.
"These results come from computations of the comet's orbit from the present to the past, which is computationally difficult due to the chaosity of the orbit caused by close encounters with Jupiter," Galiazzo said. "Thus, the details are obscure but we can establish a dynamical pathway from its current orbit back to the Kuiper belt."

Credit: University of Western Ontario
Galiazzo and Wiegert think 67P/Churyumov-Gerasimenko is relatively new to the inner parts of our solar system, having only arrived about 10,000 years ago. Prior to this time, the comet would have been inactive in frozen storage far from the sun.
Previous studies show similar comets – known as Jupiter Family comets – historically stay in the inner parts of our solar system for 12,000 years, therefore recognizing comet 67P/Churyumov-Gerasimenko as a member of the Jupiter Family makes sense.
The majority of the Jupiter Family comets are thought to come from the Kuiper belt – a ring-shaped accumulation of comets, asteroids and other space bodies in the solar system beyond the known planets. Galiazzo and Wiegert believe, based on initial analysis of their investigation, this is the case for 67P/Churyumov-Gerasimenko, as well.
Their analysis shows that, in transit, the comet likely spent millions of years in the scattering disk, a distant portion of the Kuiper belt, at about twice the distance of Neptune, our solar system's most distant planet. This distant origin for 67P/Churyumov-Gerasimenko implies it would be made from primordial material, meaning minerals that existed in their current form since before Earth was formed.
[Image: 1x1.gif] Explore further: Final descent image from Rosetta spacecraft
Provided by: University of Western Ontario

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Comet 67P/Churyumov-Gerasimenko is much younger than previously thought  youareaduck
November 9, 2016

[Image: churycometis.jpg]
Credit: ESA/Rosetta/NAVCAM CC BY-SA IGO 3.0
Based on computer simulations, astrophysicists at the University of Bern, Switzerland, conclude that the comet Chury did not obtain its duck-like form during the formation of our solar system 4.5 billion years ago. Although it does contain primordial material, they are able to show that the comet in its present form is hardly more than a billion years old.

Based on data from the Rosetta space probe, scientists have so far assumed that the comet 67P/Churyumov–Gerasimenko originated from the initial phase of our solar system. Its peculiar, duck-shaped structure would have resulted from a gentle collision of two objects about 4.5 billion years ago.
Based on new research, Martin Jutzi and Willy Benz from NCCR PlanetS and the Center for Space and Habitability (CSH) of the University of Bern, together with colleagues, have now come to a different conclusion. As a result of two studies published in the specialist journal Astronomy & Astrophysics, astrophysicist Martin Jutzi explains that "It is unlikely that a body like Chury has survived for such a long time without damage—our computer simulations show this. "
If the assumptions of the present "standard" model of the origin of our solar system are correct, a quiet initial phase was followed by a period in which large bodies initiated higher velocities and more violent collisions. In a first study, the scientists calculated how much energy would be needed to destroy a structure like Chury in a collision. As it turned out, Chury has a weak point: the connection between the two lobes—the "neck" between the "head" and the "body."

Comet 67P/C-G shape formation by sub-catastrophic collisions. The animation shows how Comet Chury’s shape could have been formed. The three scenarios have different initial conditions. Credit: Animation by M. Jutzi and W. Benz, University of Bern
"We have found that this structure can be destroyed easily, even with low energy collisions," Martin Jutzi summarizes. Willy Benz compares the neck of the comet with the stem of a glass: "A dishwasher has to clean very gently, so that the stem of the glass does not break," says the astrophysicist. Obviously, the solar system did not handle this aspect as carefully.
The new study shows that comets like Chury experienced a significant number of collisions over time, the energy of which would have been sufficient to destroy a bi-lobe structure. Therefore, the shape is not primordial, but has developed through collisions over billions of years. "Chury's present shape is the result of the last major impact which probably occurred within the last billion years," says Martin Jutzi. The duck-shaped Chury is therefore much younger than previously thought. The only alternative would be that the current standard model of the early evolution of the solar system is not correct and there were fewer small objects than previously thought. In this case there would not have been as many collisions and Chury would have had the chance to keep its primordial shape. "At the moment, we do think though that Chury's shape is the result of many collisions, and that the standard modeldoesn't need to be revised," says Jutzi.

New shape, same content
In the second paper, Jutzi and Benz investigate exactly how Chury's current form could have resulted from a collision. In their computer models, they had small objects with a diameter of 200 to 400 meters crashing into a roughly five-kilometre, rotating body in the form of a rugby ball. The impact speed was in the range of 200 to 300 meters per second, which clearly exceeds the escape velocity for objects of this size (about 1 meter per second). However, the energy involved is still far below that of a catastrophic impact in which a large part of the body is pulverized. As a result, the target was torn in two parts, which, due to the effects of their mutual gravitational force, later merged into a structure with two parts—a structure like Chury.
Does the result of this research contradict previous knowledge that comets consist of primordial material at least as old as our solar system? "No," the researchers say. Their computer simulations show that the relatively small impact energy does not heat or compress the comet globally. The body is still porous and the volatile material which was contained in it since the beginning is retained. In connection with Chury, these properties could be measured convincingly with the space probe Rosetta. "So far, it has been assumed that comets are original building blocks - similar to Lego," says Willy Benz. "Our work shows that the Lego blocks no longer have their original form, but the plastic that they consist of is still the same as in the beginning."
[Image: 1x1.gif] Explore further: How comets were assembled
More information: M. Jutzi et al.: How primordial ist the structure of comet 67P/c-G?, Astronomy & Astrophysics, 9. November 2016,
M. Jutzi, W. Benz: Formation of bi-lobed shapes by sub-catastrophic collisions – A late originin of comet 67P/C-G's structure, Astronomy & Astrophysics, 9. November 2016, 
Journal reference: Astronomy & Astrophysics [Image: img-dot.gif] [Image: img-dot.gif]
Provided by: University of Bern
You know what that last article means  Hmm2

Quote:Based on computer simulations, 
astrophysicists at the University of Bern, Switzerland, 
conclude that the comet Chury 
did not obtain its duck-like form during the formation of our solar system 4.5 billion years ago Nonono 

Although it does contain primordial material, 
they are able to show that the comet in its present form is hardly more than a billion years old.

It means that the New Horizons spacecraft is wasting it's mission time,
going out to Fly Hi Bye the MU69 ice cobble in the Kuiper belt.

Quote:Therefore, the shape is not primordial,
but has developed
through collisions over billions of years.

The scientists point out that the comet has only been in the inner solar system about 10,000 years.

Quote:Galiazzo and Wiegert think 67P/Churyumov-Gerasimenko is relatively new to the inner parts of our solar system, 
having only arrived about 10,000 years ago

So the comet was originally languishing about in the Kuiper Belt ... just like the MU69 ice cobble,
for a billion or + - years,
where both of them  encountered high percentage chances of multiple collisions over vast time.

The comet and MU69, and all the rest of those Kuiper Belt Frozen Dirt Boogers,
are all kissing cousins, and they have been making whoopie for billions of years.

This means that any Jupiter family comet in the inner solar system originating from the Kuiper Belt,
will certainly reveal just about as much data and info about the "primordial solar system"
as any Kuiper Belt frozen piece of shit ... like MU69,
sitting out there in the Kuiper belt ... with a hit me sign as a target.

That is a smoking gun on the entire Pluto mission failure ... to stay put orbiting Pluto.

They would have learned more about the "primordial solar system formation"
from observing Pluto in recurrent spacecraft orbital research,
than the impending frozen booger MU69 Fly  Hi Bye.
Icy surprises at Rosetta's comet
November 18, 2016

[Image: icysurprises.jpg]
First detection of carbon dioxide at a comet. Credit: data: ESA/Rosetta/VIRTIS/INAF-IAPS/OBS DE PARIS-LESIA/DLR; Reprinted with permission from G. Filacchione et al., Science 10.1126/science.aag3161 (2016); context image: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0

As Rosetta's comet approached its most active period last year, the spacecraft spotted carbon dioxide ice – never before seen on a comet – followed by the emergence of two unusually large patches of water ice.

The carbon dioxide ice layer covered an area comparable to the size of a football pitch, while the two water ice patches were each larger than an Olympic swimming pool and much larger than any signs of water ice previously spotted at the comet.
The three icy layers were all found in the same region, on the comet's southern hemisphere.
A combination of the complex shape of the comet, its elongated path around the Sun and the substantial tilt of its spin, seasons are spread unequally between the two hemispheres of the double-lobed Comet 67P/Churyumov-Gerasimenko.
When Rosetta arrived in August 2014, the northern hemisphere was still undergoing its 5.5 year summer, while the southern hemisphere was in winter and much of it was shrouded in darkness.
However, shortly before the comet's closest approach to the Sun in August 2015, the seasons changed and the southern hemisphere experienced a brief but intense summer, exposing this region to sunlight again.
In the first half of 2015, as the comet steadily became more active, Rosetta observed water vapour and other gases pouring out of the nucleus, lifting its dusty cover and revealing some of the comet's icy secrets.


Sequence of 23 images of Comet 67P/Churyumov-Gerasimenko taken with Rosetta's OSIRIS narrow-angle camera on 4 July 2015, about a month before the comet's closest approach to the Sun. The three-colour images are made from observations at 480, 649 and 882 nm. The images are taken at 30 minute intervals and span a full day at the comet, which spins around its axis in about 12.4 hours. The Sun is towards the top of the frame. The sequence reveals daily colour variations on the surface, with bluer portions of the surface being richer in water ice than their redder surroundings. A daily cycle of water ice occurs at the comet: quickly turning into water vapour when exposed to sunlight during the local daytime, it condenses back into thin layers of frost and ice as the temperature decreases after sunset, only to sublimate again on the following day. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
In particular, on two occasions in late March 2015, Rosetta's visible, infrared and thermal imaging spectrometer, VIRTIS, found a very large patch of carbon dioxide ice in the Anhur region, in the comet's southern hemisphere.
This is the first detection of solid carbon dioxide on any comet, although it is not uncommon in the Solar System – it is abundant in the polar caps of Mars, for example.
"We know comets contain carbon dioxide, which is one of the most abundant species in cometary atmospheres after water, but it's extremely difficult to observe it in solid form on the surface," explains Gianrico Filacchione from Italy's INAF-IAPS Istituto di Astrofisica e Planetologia Spaziali, who led the study.
In the comet environment, carbon dioxide freezes at -193°C, much below the temperature where water turns into ice. Above this temperature, it changes directly from a solid to a gas, hampering its detection in ice form on the surface.

By contrast, water ice has been found at various comets, and Rosetta detected plenty of small patches on several regions.
"We hoped to find signs of carbon dioxide ice and had been looking for it for quite a while, but it was definitely a surprise when we finally detected its unmistakable signature," adds Gianrico.
The patch, consisting of a few percent of carbon dioxide ice combined with a darker blend of dust and organic material, was observed on two consecutive days in March. This was a lucky catch: when the team looked at that region again around three weeks later, it was gone.
[Image: 1-icysurprises.jpg]
Large patches of water ice found on comet surface. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; Reprinted with permission from S. Fornasier et al., Science 10.1126/science.aag2671 (2016)
Assuming that all of the ice had turned into gas, the scientists estimated that the 80 m × 60 m patch contained about 57 kg of carbon dioxide, corresponding to a 9 cm-thick layer. Its presence on the surface is likely an isolated rare case, with the majority of carbon dioxide ice being confined to deeper layers of the nucleus.
Gianrico and his collaborators believe the icy patch dates back a few years, when the comet was still in the cold reaches of the outer Solar System and the southern hemisphere was experiencing its long winter. At that time, some of the carbon dioxide still outgassing from the interior of the nucleus condensed on the surface, where it remained frozen for a very long while, and vaporised only as the local temperature finally rose again in April 2015.
This reveals a seasonal cycle of carbon dioxide ice, which unfolds over the comet's 6.5 year orbit, as opposed to the daily cycle of water ice, also spotted by VIRTIS shortly after Rosetta's arrival.
Interestingly, shortly after the carbon dioxide ice had disappeared, Rosetta's OSIRIS narrow-angle camera detected two unusually large patches of water ice in the same area, between the southern regions of Anhur and Bes.
"We had already seen many metre-sized patches of exposed water ice in various regions of the comet, but the new detections are much larger, spanning some 30 m × 40 m each, and they persisted for about 10 days before they completely disappeared," says Sonia Fornasier from LESIA–Observatoire de Paris and Université Paris Diderot, France, lead scientist of the study focusing on seasonal and daily surface colour variations.
These ice-rich areas appear as very bright portions of the comet surface reflecting light that is bluer in colour compared with the redder surroundings. Scientists have experimented with mixtures of dust and water ice to show that, as the concentration of ice in them increases, the reflected light becomes gradually bluer in colour, until reaching a point where equal amounts of light are reflected in all colours.
The two newly detected patches contain 20–30% of water ice mixed with darker material, forming a layer up to 30 cm thick of solid ice. One of them was likely lurking underneath the carbon dioxide ice sheet revealed by VIRTIS about a month before.
[Image: 2-icysurprises.jpg]
Seasonal cycle of water ice at comet 67P/C-G. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; Reprinted with permission from S. Fornasier et al., Science 10.1126/science.aag2671 (2016)
"On a global scale, we also found that the entire comet surface turned increasingly bluer in colour as it approached the Sun and the intense activity lifted off large amounts of dust, exposing more of the ice-rich terrain underneath," explains Sonia.
As the comet moved away from the Sun, the scientists observed the overall colour of the comet surface gradually turning redder again.
They also revealed local variations of colour, indicative of the daily cycle of water ice. Quickly turning into water vapour when exposed to sunlight during the local daytime, it condensed back into thin layers of frost and ice as the temperature decreases after sunset, only to vaporise again on the following day.
The distribution of water ice beneath the dusty surface of the comet seems widely but not uniformly spread, with small patches punctuating the nucleus, appearing and disappearing as a result of the comet's activity.
Occasionally, larger and thicker portions of ice are also uncovered, dating back to a previous approach to the Sun.
"These two studies of the comet's icy content are revealing new details about the composition and history of the nucleus," says Matt Taylor, ESA Rosetta project scientist.
"While the flight part of the mission is now over, the scientific exploitation of the enormous quantity of data collected by Rosetta continues."

"Seasonal exposure of carbon dioxide ice on the nucleus of comet 67P/Churyumov-Gerasimenko" by G. Filacchione et al. and "Rosetta's comet 67P/Churyumov-Gerasimenko sheds its dusty mantle to reveal its icy nature" by S. Fornasier et al. are published in the journal Science.
[Image: 1x1.gif] Explore further: Far away, so close
More information: G. Filacchione et al. Seasonal exposure of carbon dioxide ice on the nucleus of comet 67P/Churyumov-Gerasimenko, Science (2016). DOI: 10.1126/science.aag3161
S. Fornasier et al. Rosettas comet 67P/Churyumov-Gerasimenko sheds its dusty mantle to reveal its icy nature, Science (2016). DOI: 10.1126/science.aag2671 
Journal reference: Science [Image: img-dot.gif] [Image: img-dot.gif]
Provided by: European Space Agency

Read more at:[/url][url=]
Rosetta's last words—science descending to a comet
December 16, 2016

[Image: rosettaslast.png]
Imaging ‘footprints’ of Rosetta’s OSIRIS camera during the descent to the comet’s surface. A primary focus was the pit named Deir el-Medina, as indicated by the number of footprints indicated in blue. The trail of orange and red squares reflect the change in pointing of the camera towards the impact site, subsequently named Sais. The final image was acquired at about 20 m above the surface, and the touchdown point was only 33 m from the centre of the predicted landing ellipse. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
ESA's Rosetta completed its incredible mission on 30 September, collecting unprecedented images and data right until the moment of contact with the comet's surface.

Rosetta's signal disappeared from screens at ESA's mission control at 11:19:37 GMT, confirming that the spacecraft had arrived on the surface of Comet 67P/Churyumov–Gerasimenko and switched off some 40 minutes earlier and 720 million kilometres from Earth.
One of the final pieces of information received from Rosetta was sent by its navigation startrackers: a report of a 'large object' in the field of view – the comet horizon.
Reconstruction of the final descent showed that the spacecraft gently struck the surface only 33 m from the target point.
The accuracy once again highlighted the excellent work of the flight dynamics specialists who supported the entire mission.
The spot, just inside an ancient pit in the Ma'at region on the comet's 'head', was named Sais, after a town where the Rosetta Stone was originally located.
Numerous images were taken of the neighbouring pit, capturing incredible details of its layered walls that will be used to help decipher the comet's geological history.
The final image was acquired about 20 m above the impact point. In addition, a number of Rosetta's dust, gas and plasma analysis instruments collected data.
[Image: rosettaslast.jpg]
Rosetta's last image of Comet 67P/Churyumov-Gerasimenko, taken with the OSIRIS wide-angle camera shortly before impact, at an estimated altitude of about 20 m above the surface. The initially reported 51 m was based on the predicted impact time. Now that this has been confirmed, and following additional information and timeline reconstruction, the estimated distance is now thought to be around 20 metres, and analysis is ongoing. The image scale is about 2 mm/pixel and the image measures about 96 cm across. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
The pressure of the gas outflow from the comet was seen to rise as the surface neared. Scans revealed temperatures between about –190ºC and –110ºC down to a few centimetres below the surface. The variation was most likely due to shadows and local topography as Rosetta flew across the surface.
A last measurement of water vapour emission was made on 27 September, estimating the comet was emitting the equivalent of two tablespoons of water per second. During its most active period in August 2015, estimates were in the region of two bathtubs' worth of water every second.
The first indications from spectral readings show there to be no significant differences in surface composition at the high resolutions obtained all the way down, and there was no obvious indication of small icy patches near the landing site.
The measurements also suggest an increase in very small dust grains – possibly around a millionth of a millimetre – close to the surface.

The last observation of the gas coma surrounding the comet was made the day before the final descent. Carbon dioxide was still being outgassed, at a greater distance from the Sun than when the comet was approaching it.
[Image: 1-rosettaslast.jpg]
Comet landing sites in context. Credit: CIVA: ESA/Rosetta/Philae/CIVA; NAVCAM: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0; OSIRIS: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; ROLIS: ESA/Rosetta/Philae/ROLIS/DLR
Stable solar wind conditions reigned during the final measurements of the solar wind and interplanetary magnetic field, providing 'quiet' background values that will be important for calibration.
Decreasing comet plasma densities were observed from about 2 km above the surface, with no obvious detection of local outgassing from the Ma'at pits.
Magnetic field measurements down to an estimated 11 m above the surface confirmed the previous observations of the comet as a non-magnetic body.
No large dust particles were collected during the descent, in itself an interesting result. First impressions are that the observed water vapour production was too low to lift dust grains above a detectable size from the surface.
"It's great to have these first insights from Rosetta's last set of data," says Matt Taylor, ESA's Rosetta Project Scientist. "Operations have been completed for over two months now, and the instrument teams are very much focused on analysing their huge datasets collected during Rosetta's two-plus years at the comet.
"Data from this period will eventually be made available in our archives in the same way as all Rosetta data."
[Image: 2-rosettaslast.jpg]
Artist's impression of Rosetta shortly before hitting Comet 67P/Churyumov–Gerasimenko on 30 September 2016. Credit: ESA/ATG medialab
[Image: 1x1.gif] Explore further: Far away, so close
Provided by: European Space Agency

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Tiny Spacecraft Sees Water at Rosetta's Comet While Stranded in Solar Orbit
By Irene Klotz, Seeker | January 27, 2017 06:40am ET
[Image: Churyumov-Gerasimenko.jpg?interpolation=...ize=*:1400]

Credit: ESA
A tiny Japanese spacecraft stranded after a botched engine burn nixed its mission to an asteroid has provided a key measurement of water in the comet that hosted Europe's Rosetta mission.
The finding supports measurements made of comet 67P/Churyumov-Gerasimenko by the Rosetta orbiter, which circled the comet for two years.
Astronomers used a telescope aboard Japan's Proximate Object Close Flyby with Optical Navigation, or PROCYON, spacecraft to look at 67P in September 2015, providing a global perspective unavailable to Rosetta, which was inside the comet's coma at the time.


"The water production rate of a comet is one of the fundamental parameters necessary to understand cometary activity… because water is the most abundant icy material in the cometary nucleus," Yoshiharu Shinnaka, with the National Astronomical Observatory of Japan, and colleagues wrote in a paper published in this week's Astronomical Journal.
RELATED: Sublime Surprise: Rosetta's Comet Cycles its Ice
Knowing how much water is in a comet also is important for understanding the process by which molecules were incorporated into comets as they formed in the early solar system, the observatory noted in a related press released.
Comet 67P wasn't in viewing range of Earth-based telescopes at the time, but PROCYON, thanks to a quirk of fate, was. The tiny satellite, weighing just 143 pounds (65 kg), was launched in December 2014 along with Japan's Hayabusa 2 asteroid sampler.
PROCYON was intended to fly by asteroid 2000 DP107, but its ion thruster failed, nixing the mission. The spacecraft remains in orbit around the sun.
Its measurements of 67P are important to validating computer models used for scientific research and possible future expeditions.
"We were able to test the coma models for the comet for the first time," the observatory's press release said, adding that the measurement was the first by a micro satellite for a deep-space mission.
"We hope this will become a model case for micro spacecraft observations in support of large missions," the observatory noted.
Image: Rosetta's shadow crosses Comet 67P/Churyumov–Gerasimenko in daring encounter
February 14, 2017

[Image: imagerosetta.png]
Valentine's Day 2015 and ESA's Rosetta swooped in towards Comet 67P/Churyumov–Gerasimenko for a daring close encounter. At just 6 km from the surface, it was the closest the spacecraft had ever been to the comet at that point in the mission.

The 14 February flyby was not only special because of its proximity, Rosetta also passed through a unique observational geometry: for a short time the Sun, craft and comet were exactly aligned. In this position, surface structures cast almost no shadows, allowing the reflection properties of the surface material to be determined.
As a side effect, Rosetta's shadow could also be seen, cast on the surface of the comet as a fuzzy rectangular dark smudge somewhat larger than Rosetta itself, in this case measuring some 20 x 50 m. The full image measures about 228 m across.
This particular image is the last in a sequence of 12 that captured the spacecraft's shadow as it tracked over the surface in the Imhotep region on the larger of the comet's two lobes.
The image was taken by the OSIRIS narrow-angle camera and the image resolution is just 11 cm/pixel.
Rosetta subsequently made closer flybys, notably in the final phase of its incredible mission as it drew ever closer to the comet before finally coming to rest on the surface in September 2016.
[Image: 1x1.gif] Explore further: OSIRIS catches glimpse of Rosetta's shadow
Provided by: European Space Agency

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