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First Image of a black hole to be released in 6 simultaneous global press conferences
#1
APRIL 6, 2019
Scientists set to unveil first picture of a black hole
by Marlowe Hood
[Image: ofalltheforc.jpg]Of all the forces or objects in the Universe that we cannot see—dark energy and dark matter—none has frustrated human curiosity so much as the invisible maws that shred and swallow entire stars like so many specks of dust, known as black holes
The world, it seems, is soon to see the first picture of a black hole.

On Wednesday, astronomers across the globe will hold "six major press conferences" simultaneously to announce the first results of the Event Horizon Telescope (EHT), which was designed precisely for that purpose.
It has been a long wait.
Of all the forces or objects in the Universe that we cannot see—including dark energy and dark matter—none has frustrated human curiosity so much as the invisible maws that shred and swallow stars like so many specks of dust.
Astronomers began speculating about these omnivorous "dark stars" in the 1700s, and since then indirect evidence has slowly accumulated.
"More than 50 years ago, scientists saw that there was something very bright at the centre of our galaxy," Paul McNamara, an astrophysicist at the European Space Agency and an expert on black holes, told AFP.
"It has a gravitational pull strong enough to make stars orbit around it very quickly—as fast as 20 years."
To put that in perspective, our Solar System takes about 230 million years to circle the centre of the Milky Way.
Eventually, astronomers speculated that these bright spots were in fact "black holes"—a term coined by American physicist John Archibald Wheeler in the mid-1960s—surrounded by a swirling band of white-hot gas and plasma.
At the inner edge of these luminous accretion disks, things abruptly go dark.
"The event horizon"—a.k.a. the point-of-no-return—"is not a physical barrier, you couldn't stand on it," McNamara explained.
"If you're on the inside of it, you can't escape because you would need infinite energy. And if you are on the other side, you can—in principle."
A golf ball on the moon
At its centre, the mass of a black hole is compressed into a single, zero-dimensional point.
The distance between this so-called "singularity" and the event horizon is the radius, or half the width, of a black hole.

The EHT that collected the data for the first-ever image is unlike any ever devised.
"Instead of constructing a giant telescope—which would collapse under its own weight—we combined several observatories as if they were fragments of a giant mirror," Michael Bremer, an astronomer at the Institute for Millimetric Radio Astronomy in Grenoble, told AFP.
[Image: atitscentert.jpg]

At its center, the mass of a black hole is compressed into a single, zero-dimensional point. The distance between this so-called "singularity" and the event horizon is the radius, or half the width, of the black hole
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In April 2017, eight such radio telescopes scattered across the globe—in Hawaii, Arizona, Spain, Mexico, Chile, and the South Pole—were trained on two black holes in very different corners of the Universe to collect data.
Studies that could be unveiled next week are likely to zoom in on one or the other.
Oddsmakers favour Sagittarius A*, the black hole at the centre of our own elliptical galaxy that first caught the eye of astronomers.
Sag A* has four million times the mass of our sun, which means that the black hole is generates is about 44 million kilometres across.
That may sound like a big target, but for the telescope array on Earth some 26,000 light-years (or 245 trillion kilometres) away, it's like trying to photograph a golf ball on the Moon.
Testing Einstein
The other candidate is a monster black hole—1,500 times more massive even than Sag A*—in an elliptical galaxy known as M87.
It's also a lot farther from Earth, but distance and size balance out, making it roughly as easy (or difficult) to pinpoint.
One reason this dark horse might be the one revealed next week is light smog within the Milky Way.
"We are sitting in the plain of our galaxy—you have to look through all the stars and dust to get to the centre," said McNamara.
The data collected by the far-flung telescope array still had to be collected and collated.
"The imaging doink-head we developed fill the gaps of data we are missing in order to reconstruct a picture of a black hole," the team said on their website.
Astrophysicists not involved in the project, including McNamara, are eagerly—perhaps anxiously—waiting to see if the findings challenge Einstein's theory of general relativity, which has never been tested on this scale.
Breakthrough observations in 2015 that earned the scientists involved a Nobel Prize used gravitational wave detectors to track two black holes smashing together.
As they merged, ripples in the curvatures of time-space creating a unique, and detectable, signature.
"Einstein's theory of general relativity says that this is exactly what should happen," said McNamara.
But those were tiny black holes—only 60 times more massive than the Sun—compared to either of the ones under the gaze of the EHT.
"Maybe the ones that are millions of times more massive are different—we just don't know yet."[/size]


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#2
Astronomers deliver first photo of black hole

[Image: 5caded214d11e.jpg]Credit: NSF
Astronomers on Wednesday unveiled the first photo of a black hole, one of the star-devouring monsters scattered throughout the Universe and obscured by impenetrable shields of gravity.

The image of a dark core encircled by a flame-orange halo of white-hot gas and plasma looks like any number of artists' renderings over the last 30 years.
But this time, it's the real deal.
Scientists have been puzzling over invisible "dark stars" since the 18th century, but never has one been spied by a telescope, much less photographed.
The supermassive black hole now immortalised by a far-flung network of radio telescopes is 50 million lightyears away in a galaxy known as M87.
"It's a distance that we could have barely imagined," Frederic Gueth, an astronomer at France's National Centre for Scientific Research (CNRS) and co-author of studies detailing the findings, told AFP.
Most speculation had centred on the other candidate targeted by the Event Horizon Telescope—Sagittarius A*, the black hole at the centre of our own galaxy, the Milky Way.
By comparison, Sag A* is only 26,000 lightyears from Earth.
Locking down an image of M87's supermassive black hole at such distance is comparable to photographing a pebble on the Moon.

European Space Agency astrophysicist Paul McNamara called it an "outstanding technical achievement".
It was also a team effort.
"Instead of constructing a giant telescope that would collapse under its own weight, we combined many observatories," Michael Bremer, an astronomer at the Institute for Millimetric Radio Astronomy (IRAM) in Grenoble, told AFP.
Earth in a thimble
Over several days in April 2017, eight radio telescopes in Hawaii, Arizona, Spain, Mexico, Chile, and the South Pole zeroed in on Sag A* and M87.
Knit together "like fragments of a giant mirror," in Bremer's words, they formed a virtual observatory some 12,000 kilometres across—roughly the diameter of Earth.
In the end, M87 was more photogenic. Like a fidgety child, Sag A* was too "active" to capture a clear picture, the researchers said.
"The telescope is not looking at the black hole per se, but the material it has captured," a luminous disk of white-hot gas and plasma known as an accretion disk, said McNamara, who was not part of the team.

"The light from behind the black hole gets bent like a lens."
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The Event Horizon Telescope (EHT) -- a planet-scale array of eight ground-based radio telescopes forged through international collaboration -- was designed to capture images of a black hole. Today, in coordinated press conferences across the globe, EHT researchers reveal that they have succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow.For more multimedia, visit NSF.gov/blackhole, including text-free versions of all images. Credit: NSF
The unprecedented image—so often imagined in science and science fiction —- has been analysed in six studies co-authored by 200 experts from 60-odd institutions and published Wednesday in Astrophysical Journal Letters.
"I never thought that I would see a real one in my lifetime," said CNRS astrophysicist Jean-Pierre Luminet, author in 1979 of the first digital simulation of a black hole.
Coined in the mid-60s by American physicist John Archibald Wheeler, the term "black hole" refers to a point in space where matter is so compressed as to create a gravity field from which even light cannot escape.
The more mass, the bigger the hole.
At the same scale of compression, Earth would fit inside a thimble. The Sun would measure a mere six kilometres edge-to-edge.
A successful outcome depended in part on the vagaries of weather during the April 2017 observation period.
"For everything to work, we needed to have clear visibility at every [telescope] location worldwide", said IRAM scientist Pablo Torne, recalling collective tension, fatigue and, finally, relief.
'Hell of a Christmas present'
Torne was at the controls of the Pico Veleta telescope in Spain's Sierra Madre mountains.
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The Event Horizon Telescope (EHT) -- a planet-scale array of eight ground-based radio telescopes forged through international collaboration -- was designed to capture images of a black hole. For more multimedia, visit NSF.gov/blackhole. Credit: NSF
After that, is was eight months of nail-biting while scientists at MIT Haystack Observatory in Massachusetts and the Max Planck Institute for Radio Astronomy in Bonn crunched the data.
The Universe is filled with electromagnetic "noise", and there was no guarantee M87's faint signals could be extracted from a mountain of data so voluminous it could not be delivered via the Internet.
There was at least one glitch.
"We were desperately waiting for the data from the South Pole Telescope, which—due to extreme weather conditions during the southern hemisphere winter—didn't arrive until six months later," recalled Helger Rottmann from the Max Planck Institute.
It arrived, to be precise, on December 23, 2017.
"When, a few hours later, we saw that everything was there, it was one hell of a Christmas present," Rottmann said.
It would take another year, however, to piece together the data into an image.
"To be absolutely sure, we did the work four times with four different teams," said Gueth.
Each team came up with exactly the same spectacular, history-making picture of a dark circle encased in a flaming-red halo.


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Along the vines of the Vineyard.
With a forked tongue the snake singsss...
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