imagery of Black Hole at center of M87 galaxy

 

Mesmerizing video shows M87 black hole as nobody has seen it before

Chris Davies - Apr 14, 2021, 2:02pm CDT

If you thought the first image of a black hole in distant galaxy M87 was something special two years ago, a newly-released video pulling together the work of 19 observatories will just about blow you away. In 2019, the Event Horizon Telescope (EHT) captured the 25 billion mile wide black hole for the very first time, but don’t let the name fool you into imagining one telescope with an astronomer’s eye pressed to the viewfinder.

The black hole at its center, however, held onto its mysteries far longer. An example of a supermassive black hole, it forced astronomers to think laterally when they wanted to capture a picture of it: after all, black holes by definition capture light. The EHT mustered data from eight different telescopes and pooled that information to create an image of the glowing gas surrounding the ink-black maw at its center, with gravitational bending causing a shadow.

The picture made headlines in 2019, but now the EHT is delivering again with more instruments and more details. “We knew that the first direct image of a black hole would be groundbreaking,” Kazuhiro Hada of the National Astronomical Observatory of Japan, a co-author of a new study being published in The Astrophysical Journal Letters to describe the new data, explained. “But to get the most out of this remarkable image, we need to know everything we can about the black hole’s behavior at that time by observing over the entire electromagnetic spectrum.”

This time, 19 observatories – including five operated by NASA – were harnessed in order to give an unprecedented tour of M87 in different wavelengths of light. It relies on the fact that the black hole’s gravitational pull can create jets of particles traveling at almost the speed of light, across the whole electromagnetic spectrum. These jets spar out across the universe, spanning radio waves through visible light to gamma rays, with different sets collected by the 19 different instruments.

The video begins with the original EHT image, and then spirals out through radio telescope arrays, across visible and then ultraviolet light, and then X-rays. Finally, there’s data from gamma ray telescopes on the ground, along with NASA’s Fermi in space.

It took 760 scientists and engineers, across 200 institutions, and over the course of March and April 2017, to piece together the vast data set. It’s not just for entertainment, either, with the potential for new scientific breakthroughs to be unlocked.

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We have the 1st photo of a black hole. Here's how it was taken

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Observations added up to 'half a tonne of hard drives,' says physicist Avery Broderick

CBC Radio · Posted: Apr 12, 2019 4:18 PM ET | Last Updated: April 12, 2019

This is the first image ever taken of the event horizon of a supermassive black hole, captured by the Event Horizon Telescope in 2017. (Event Horizon Telescope)

Quirks and Quarks8:30Seeing the first black hole - and what we'll see next

Some have likened it to a blurry orange doughnut, but it took a team of over 200 scientists, eight special telescopes and churning through millions of gigabytes of data to capture the first image of a black hole.

Astronomers captured the image using the Event Horizon Telescope (EHT) — a "virtual telescope" — that produces an extremely high-resolution image by combining data from eight radio telescopes around the world. The black hole has been unofficially named Powehi, a Hawaiian name meaning "the adorned fathomless dark creation" or "embellished dark source of unending creation."

Black holes are very difficult to image, since anything that crosses a critical threshold near the black hole — known as the event horizon — gets pulled inside, even light. As a result, nothing inside the event horizon can ever be seen.

What the team captured in their picture was light from the material about to pass over the event horizon, according to Avery Broderick, a physicist from the University of Waterloo and the Perimeter Institute, who is also a member of the international EHT team.

Avery Broderick is a Canadian physicist. (University of Waterloo)

"It's a churning maelstrom of superheated plasma, hundreds of billions of degrees," he said of the matter observed around the black hole. 

It's not just the nature of the black holes that makes them difficult to photograph. Observations from multiple telescopes that make up the EHT also added up to a lot of data — five petabytes, to be exact, which translates to five million gigabytes.

Broderick spoke with Quirks & Quarks host Bob McDonald about the efforts to capture this iconic picture. Here is part of their conversation:

Tell me about the virtual telescope that you used to capture this image.

The Event Horizon Telescope is a combination of existing facilities. So we've really leveraged an enormous amount of investment over the past two decades in radio astronomy and brought them together, added specialized equipment to each of the six sites the eight telescopes are located at, so they could be brought together to form a single new instrument — and that's what the Event Horizon Telescope is.

Image taken during a time-lapse at the Atacama Large Millimeter/submillimeter Array (ALMA) in the Chilean Andes. ALMA is one of the instruments in the Event Horizon Telescope. (C. Malin/ ALMA)

We take data [from] each of these sites and then we have to bring that data physically back together at special supercomputing locations, where it gets combined to produce the information that goes into producing these images.

• Earth-sized telescope found its roots in Canada: Bob McDonald

How much data are you talking about?

For the 2017 observations, there were five petabytes. That's literally half a tonne of hard drives.

When you did finally go through all of that, what did you actually learn from this image?

Just like any other human, I see something and it becomes more real to me.

And now we can say that in a scientific sense, too. Now we have this prediction from general relativity, it's very unambiguous and that's a rare occurrence. There was really no wiggle room here.

Because we saw what we had anticipated, now we have confidence that general relativity applies not just where it makes small corrections to Newton's theory of gravity. We're seeing it where general relativity is the entire story — where gravity has run amok. And so now we've in some sense book-ended the regions where we can trust Einstein's theory.

We've opened a new window, but we're not done looking through it.- Avery Broderick

What was it like for you, since you predicted what this thing might look like, to see that it actually turned out to be what you thought?

It's a complex set of emotions. I was relieved after spending so much time that it came out to be something like we had thought — that the project has been successful and produced the images we always hoped it would.

You know, one of the great joys of being a scientist is when nature unfolds itself just a little bit to you, you're the first to see that. And then you have the privilege of going around telling the world. But there's also excitement, because this is the beginning. We've opened a new window, but we're not done looking through it.

Tell me about the black hole that's behind this image.

M87 [the galaxy] harbours a 6.5-billion solar mass black hole. That's a behemoth by any standard. Now, every galaxy has something like this. At the centre of our Milky Way is a four-million solar mass black hole. This is almost 2,000 times larger.

The black hole in the M87 galaxy produces a powerful jet of subatomic particles travelling at nearly the speed of light. In this Hubble telescope image, the blue jet contrasts with the yellow glow from the combined light of billions of unresolved stars and the point-like clusters of stars that make up this galaxy. (NASA and the Hubble Heritage Team/STScI/AURA)

So why did you choose that one as a target for the Event Horizon Telescope?

Since the telescope is looking out on the sky, we don't care if you're the largest black hole and we don't care if you're the closest black hole. You have to be large and close and the way you balance those is it's really how massive [the hole is] divided by how far.

M87 is 2,000 times more massive than the black hole in our galaxy, which is good. It's also about 2,000 times farther away. So it turns out it's about the same size as the one in our Milky Way.

But that additional mass has another effect. Black holes are in a highly dynamical region — things are swirling about them. And the time scale it takes for stuff to go around M87 is about a week, and as a result, it's stationary during the night.

We have to be looking at not black hole portraiture, but black hole cinema.- Avery Broderick

You've talked about looking at the black hole that's at the centre of our own galaxy, the Milky Way. How will that be different from the process of imaging M87's black hole?

The chief complication with the Milky Way's black hole is that it really is much smaller in mass, even though it's closer. And that means the time scales for things changing are shorter. They can be as short as minutes.

That's a challenge, but it's also an enormous opportunity. That time variability means we have to be looking at not black hole portraiture, but black hole cinema. And just as a picture is worth a thousand words, a movie is worth a thousand words 25 times per second.

That's going to give us an enormous amount of additional information that we can leverage. But it is a complication, and we are up to that task and we are embarking on it now.

The Milky Way, our own galaxy, hosts a black hole of about 4 million solar masses called Sagittarius A* in its central bulge. The EHT has targeted this black hole for imaging as well. (ESO/S. Brunier)

What's next for the Event Horizon Telescope?

I think, like so many scientists, I am in love with Einstein's theory. I think it's a beautiful theory. I'd like to see evidence for what's next.

I would like to see something that isn't predicted by general relativity. I'd like to see the loose thread that we're going to pull and we're going to unravel what comes after general relativity.