Remember the first picture of a black hole in our galaxy? we took it


Black holes are one of Einstein’s most profound predictions of general relativity. Originally studied as a mere mathematical consequence of a theory rather than a physically related object, it was soon thought to be the general and sometimes unavoidable consequence of the gravitational collapse that formed galaxies.

In fact, most physicists suspected that our galaxy was revolving around a supermassive black hole at its center. There are other ideas, such as “dark matter” (invisible matter thought to make up most of the matter in the universe). But now there is an international team of astronomers, including the team I led at Central Lancashire University. First image released The object lurking at the center of our galaxy is a supermassive black hole.

This means that there is overwhelming evidence for a black hole currently designated Sagittarius A*. Being close to such a beast may seem a little scary, but in reality it is about 26,000 light-years away, so it’s reassuring. In fact, black holes are so far away from Earth that when viewed from the sky, they appear to be about the same size as a donut would have on the moon. Sagittarius A* also appears somewhat inactive. It does not swallow a lot of substances around it.

Our team was part of a global Event Horizon Telescope (EHT) collaboration that used observations from a global network of eight radio telescopes on Earth to capture stunning images with a single Earth-sized virtual telescope. Breakthroughs with the 2019 release of the collaboration first black hole imageCalled M87*, at the center of a more distant Messier 87 Galaxy.

looking into the dark

The team observed Sagittarius A* at multiple nights, collecting data over several consecutive hours, similar to using a long exposure time on a camera. We cannot see the black hole itself, but because it is completely dark, the surrounding glowing gas shows a dark central region (called a “shadow”) surrounded by a bright ring-shaped structure. The new perspective captures light bent by the powerful gravitational pull of a black hole 4 million times more massive than our Sun. The discovery also provides valuable clues into the workings of the black hole thought to be at the center of most galaxies.

ALMA – One of the Event Horizon telescopes. Image: Wikipedia, CC BY-SA

What’s surprising about this image is that it is very similar to the image of the M87* we posted 3 years ago. This was definitely surprising. A similar reason is that the M87* black hole is about 1,000 times larger, while the Sagittarius black hole is about 100 times closer. Both follow Einstein’s theory of general relativity and show that Einstein was 1,000 times right on the size scale. For physicists, this is important. The theory of relativity has been around for a century and is still proving to be correct. I think Einstein himself would have been surprised by it too!

The release of a photograph of the Sagittarius A* black hole is a remarkable achievement of this collaboration. When I first saw the image, I thought this could tell us a lot. I couldn’t wait to write about it and start interpreting the images. We’ve had a lot of meetings to come to an agreement on what it tells us. First of all, we were meeting face-to-face in different parts of the world. Then Corona hit and suddenly no one was able to go. So, as in all other aspects of life, online conferencing has become the norm. This definitely slowed us down.

My role was to write these two things: six paper Published in Astrophysical Journal Letters: the first introducing observations; The third is to discuss how the drawings were made as a result of observations and how reliable those images were.

Also, I was a “contributing author” for all six papers. This is the administrative role that handles all correspondence between our team of more than 300 astronomers and the journal that publishes our research results. This was a challenge because I had to deal with every typo and every mistake in the typesetting.

I also had to convey the opinions of my colleagues. Since most of our collaborators are based in the US or East Asia, this means they worked at night in UK time. So every morning I went to work to find 100 or so nightly emails from my co-workers. The start of the day was overwhelming.

Anyway, we finally got there. And the dazzling results were worth all the effort.conversation

This article is Derek Ward-Thompsonprofessor of astrophysics, Central Lancashire University, is reissued from conversation Under Creative Commons License. read original article.



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