[ad_1]
PARIS: 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 tear 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 Paul McNamara, astrophysicist at the European Space Agency and expert of the holes black.
"Its gravitational pull is powerful enough for stars to revolve around it very quickly – barely 20 years later." To put this in perspective, our solar system takes about 230 million years to encircle the center of the Milky Way.
Finally, astronomers speculated that these bright dots 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" – that is, the point of no return – "is not a physical barrier, you can not stick to it," said McNamara.
"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. In the center, the mass of a black hole is compressed 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.
Posted in Dawn, April 7, 2019
[ad_2]
Source link