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Of all the forces or objects in the universe that we can not see – black energy and dark matter – none has so upset human curiosity as the invisible mews that shred and swallow whole stars like so much dust called black holes.
The world, it seems, will soon see the first image of a black hole.
On Wednesday, astronomers from around the world will simultaneously hold "six major press conferences" to announce the first results of the Event Horizon Telescope (EHT), designed specifically for this purpose.
It has been a long wait.
Of all the forces or objects in the universe that we can not see, including dark energy and dark matter, none has so upset human curiosity as the unseen meows that shred and swallow the stars like so much dust.
Astronomers began to speculate on these omnivorous "black stars" in the 1700s, and since then indirect evidence has slowly accumulated.
"More than 50 years ago, scientists found that there was something very bright at the center of our galaxy," said AFP Paul McNamara, astrophysicist at the agency. European Space and Black Hole Expert.
"It has an attraction force strong enough for stars to revolve around it very quickly – as fast as 20 years."
To put this into perspective, it takes our solar system about 230 million years to encircle the center of the Milky Way.
Finally, astronomers speculated that these luminous points were actually "black holes" – a term invented by the 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 darken suddenly.
"The horizon of events" – a.k.a. The point of no return – "is not a physical barrier, you can not stand on it," McNamara explained.
"If you are inside, you can not 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 center, the mass of a black hole is squeezed into a single point of zero dimension.
The distance between this so-called "singularity" and the event horizon corresponds to the radius, or half the width, of a black hole.
The EHT who collected the data for the very first image is one of a kind.
"Instead of building a giant telescope – which would collapse under its own weight – we have combined several observatories as if it were fragments of a giant mirror," he said. AFP Michael Bremer, astronomer at the Millimeter Radioastronomy Institute of Grenoble.
At its center, the mass of a black hole is squeezed into a single point of zero dimension. The distance between this so-called "singularity" and the event horizon is the radius or half the width of the black hole.
In April 2017, eight radio telescopes scattered around the world – in Hawaii, Arizona, Spain, Mexico, Chile and the South Pole – were trained on two black holes located in very different corners of the world. 39 Universe to collect data.
Studies that may be unveiled next week may focus on one or the other.
The odds creators prefer Sagittarius A *, the black hole located at the center of our own elliptical galaxy that has attracted the attention of astronomers.
Sag A * has four million times the mass of our sun, which means that the black hole generated is about 44 million kilometers in diameter.
This may seem like a big target, but for the Earth's telescope network some 26,000 light-years away (or 245 trillion miles), it's like trying to photograph a golf ball on the moon.
Test Einstein
The other candidate is a black monster – 1500 times more massive than Sag A * – in an elliptical galaxy called M87.
It is also much farther from Earth, but the distance and size balance, making it about as easy (or difficult) to locate.
One reason this black horse could be the one to be revealed next week is light smog in 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 center," McNamara said.
The data collected by the far-distant telescope network still had to be collected and collected.
"The imaging algorithms that we have developed fill gaps in missing data to reconstruct the image of a black hole," the team said on its website.
Astrophysicists not involved in the project, including McNamara, are eagerly awaiting – perhaps anxiously – whether the findings question Einstein's theory of general relativity, which has never been tested at this scale.
In 2015, scientists had the opportunity to observe groundbreaking discoveries involving a Nobel detector using gravitational wave detectors to detect two black holes being crushed.
As they merge, ripples in the curvatures of space-time create a unique and detectable signature.
"Einstein's theory of general relativity says that's exactly what should happen," McNamara said.
But these were tiny black holes, 60 times more massive than the Sun, compared to one or the other of those observed under EHT 's gaze.
"Perhaps those who are millions of times more massive are different, we do not know yet."
© 2019 AFP
Quote:
Scientists unveil first image of a black hole (April 6, 2019)
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