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Scientists set to reveal first true image of black hole



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<figcaption class=                 Artist's impression of a black hole surrounded by matter waiting to fall into
            

The world is finally about to see a black hole — not an artist's impression or a computer-generated likeness, but the real thing.
                                               


At six press conferences scheduled for 1

300 GMT (0900 ET) on Wednesday, scientists will unveil the first results from the Event Horizon Telescope (EHT), conceived precisely for that purpose.

It has been a long wait.

Of all the forces in the universe that we can see — including dark energy and dark matter — none has frustrated human curiosity as thoroughly as the invisible, star-devouring monsters known as black holes.

Yet, the phenomena are virtually non-existent — not even light — can escape their gravitational pull.

"Over the years, we indirectly accumulated observational evidence," said Paul McNamara, an astrophysicist at the European Space Agency and project scientist for the LISA mission to track massive black hole mergers from space.

In September 2015, for example, the LIGO gravitational wave detectors in the United States measured two black holes smashing together.

"X-rays, radio-waves, light-they all point to very compact objects, and the gravitational waves confirmed that they are really black holes, even if we never actually saw one," McNamara told AFP. 19659004] Two candidates are vying to be in the first ever image.

Oddsmakers favor Sagittarius A *, the black hole at the center of our own spiral galaxy, the Milky Way.

 World map showing the network of telescopes which formed an earth-sized virtual telescope to capture the first image of a black "title =" World map showing the network of telescopes which formed an earth-sized virtual telescope to capture the first image of a black hole in outer space "/> 
 
<figcaption class=                 World map showing the network of telescopes which formed an earth-sized virtual telescope to capture the first image of a black hole in outer space
            

Sag A * has four million times the mass of our Sun, and measures about 24 million kilometers across.

That may sound like the big target, but for the telescope array on Earth some 26,000 light years (245 trillion kilometers (19659004) The other candidate is 1,500 times more massive still, and it is also known as M87.

Comparing the two, distance and size balance out, making it roughly as easy (or hard) to pinpoint either.

Ripples in time-space

A black hole is a celestial object that compresses a huge mass into an extremely small space. The more massive, the larger the black hole

At the same scale of compression, Earth's mass would fit inside a thimble, while the Sun's would be more six kilometers from edge to edge.

There are two types.

Garden-variety black holes — up to 20 times more than the Sun — form when the center of a very big star collapses in on itself.

So-called supermassive black holes are at least a million times bigger than the Sun. Both in this category and in the category

 At its center, the mass of a black hole is compressed into a single, zero-dimensional point. The distance between this so-called "title =" 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 "/> 
 
<figcaption class=                 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
            

The EHT is unlike any star-gazing instrument ever devised

"Instead of constructing a telescope we combined several observatories as fragments of giant mirror," Michael Bremer, an astronomer at the Institute for Millimetric Radio Astronomy in Grenoble, customs AFP.

Eight such radio telescopes scattered across the globe — in Hawaii, Arizona, Spain, Mexico, Chile, and the South Pole — zeroed in Sag A * and M87 on four different days in April 2017.

Each is at least a big as a football pitch. Together, they are more than 12,000 kilometers across, the diameter of Earth

Data collected by the array was collated by supercomputers at MIT in Boston and in Bonn, Germany.

"The we are missing in order to reconstruct a picture, "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.

The LIGO experiments from 2015 detected signature ripples in the curvatures of time-space during the black hole merger.

"Einstein's theory of general relativity says that this is exactly what should happen," McNamara said.

But those were tiny black holes compared with either of the ones under the gaze of the EHT.

"Maybe the one that is millions of times more massive are different – we just don't know yet, "McNamara said.
                                                                                                                        


Scientists set to unveil first picture of a black hole


© 2019 AFP
                                            

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                                                 Scientists set to reveal first true image of black hole (2019, April 10)
                                                 retrieved April 10, 2019
                                                 from https://phys.org/news/2019-04-scientists-reveal-true-image-black.html
                                            

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