The Event Horizon Telescope (EHT) -- a planet-scale array of eight ground-based radio telescopes forged through international collaboration -- was designed to capture images of a black hole. Today, in coordinated press conferences across the globe, EHT researchers reveal that they have succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow. This breakthrough was announced in a series of six papers published in a special issue of The Astrophysical Journal Letters. The image reveals the black hole at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides 55 million light-years from Earth and has a mass 6.5-billion times that of the Sun.
National Science Foundation
The Event Horizon Telescope (EHT) -- a planet-scale array of eight ground-based radio telescopes forged through international collaboration -- was designed to capture images of a black hole. Today, in coordinated press conferences across the globe, EHT researchers reveal that they have succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow. This breakthrough was announced in a series of six papers published in a special issue of The Astrophysical Journal Letters. The image reveals the black hole at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides 55 million light-years from Earth and has a mass 6.5-billion times that of the Sun.
Now playing
01:25
How the first photo of a black hole was captured
People cross a street as they make their way towards Chicago's Wrigley Field during baseball game, Friday, June 11, 2021, as Chicago and rest of Illinois fully reopens ending an over a year-long COVID-19 restrictions. (AP Photo/Shafkat Anowar)
Shafkat Anowar/AP
People cross a street as they make their way towards Chicago's Wrigley Field during baseball game, Friday, June 11, 2021, as Chicago and rest of Illinois fully reopens ending an over a year-long COVID-19 restrictions. (AP Photo/Shafkat Anowar)
Now playing
02:13
Vaccination rates lag in some states as more cities reopen
U.S. District Court
Now playing
02:45
Chicago police officer charged in connection to January 6 Capitol riot
CNN
Now playing
02:02
Barr's answer draws scrutiny amid new scandal
Deep State Dogs
Now playing
03:29
See how internet sleuths are hunting down insurrectionists
Vladimir Putin NBC intv
NBC
Vladimir Putin NBC intv
Now playing
04:22
Hear how Putin compared Donald Trump to Joe Biden
Georgia Secretary of State Brad Raffensperger speaks during a news conference on Wednesday, November 11, 2020, in Atlanta.
Brynn Anderson/AP
Georgia Secretary of State Brad Raffensperger speaks during a news conference on Wednesday, November 11, 2020, in Atlanta.
Now playing
02:35
Family of GA secretary of state got death threats months after election
Britain's Catherine, Duchess of Cambridge and US First Lady Jill Biden visit Connor Downs Academy in Hayle, Cornwall on the sidelines of the G7 summit on June 11, 2021. (Photo by DANIEL LEAL-OLIVAS / various sources / AFP) (Photo by DANIEL LEAL-OLIVAS/AFP via Getty Images)
Daniel Leal-Olivas/AFP/Getty Images
Britain's Catherine, Duchess of Cambridge and US First Lady Jill Biden visit Connor Downs Academy in Hayle, Cornwall on the sidelines of the G7 summit on June 11, 2021. (Photo by DANIEL LEAL-OLIVAS / various sources / AFP) (Photo by DANIEL LEAL-OLIVAS/AFP via Getty Images)
Now playing
01:26
See Jill Biden and the Duchess of Cambridge host school roundtable
Austin-Travis County EMS
Now playing
00:45
Video: Boat dangling from the edge of dam rescued
NEW YORK, NEW YORK - JANUARY 28: People walk by a GameStop store in Brooklyn on January 28, 2021 in New York City. Markets continue a volatile streak with the Dow Jones Industrial Average rising over 500 points in morning trading following yesterdays losses. Shares of the video game retailer GameStop plunged. (Photo by Spencer Platt/Getty Images)
Spencer Platt/Getty Images
NEW YORK, NEW YORK - JANUARY 28: People walk by a GameStop store in Brooklyn on January 28, 2021 in New York City. Markets continue a volatile streak with the Dow Jones Industrial Average rising over 500 points in morning trading following yesterdays losses. Shares of the video game retailer GameStop plunged. (Photo by Spencer Platt/Getty Images)
Now playing
01:58
Fund manager says meme stock phenomenon is not a fad
Celebrity Cruises, Inc.
Now playing
02:10
'This was inevitable': CNN reporter on cruise ship passengers
Now playing
02:43
'It's a troll': CNN reporter on Jill Biden's 'love' jacket
CNN
Now playing
02:32
Schiff reacts to DOJ subpoena: Shocked ... but not surprised
Now playing
02:37
Pregnant woman's car spins out and flips after being hit by an officer
In this photo provided by the North Korean government, North Korean leader Kim Jong Un claps his hands at the ruling party congress in Pyongyang, North Korean, Sunday, Jan. 10, 2021. Kim was given a new title, "general secretary" of the ruling Workers' Party, formerly held by his late father and grandfather, state media reported Monday, Jan. 11, in what appears to a symbolic move aimed at bolstering his authority amid growing economic challenges. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. Korean language watermark on image as provided by source reads: "KCNA" which is the abbreviation for Korean Central News Agency. (Korean Central News Agency/Korea News Service via AP)
KCNA/AP
In this photo provided by the North Korean government, North Korean leader Kim Jong Un claps his hands at the ruling party congress in Pyongyang, North Korean, Sunday, Jan. 10, 2021. Kim was given a new title, "general secretary" of the ruling Workers' Party, formerly held by his late father and grandfather, state media reported Monday, Jan. 11, in what appears to a symbolic move aimed at bolstering his authority amid growing economic challenges. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. Korean language watermark on image as provided by source reads: "KCNA" which is the abbreviation for Korean Central News Agency. (Korean Central News Agency/Korea News Service via AP)
Now playing
02:23
How Kim Jong Un's weight could have geopolitical consequences
Now playing
02:30
Hear why state lawmaker was happy anti-vaccine doc testified
Brown Family
Now playing
02:34
State autopsy confirms what Andrew Brown Jr. family asserted for weeks

Editor’s Note: Don Lincoln is a senior scientist at the Fermi National Accelerator Laboratory. He is the author of “The Large Hadron Collider: The Extraordinary Story of the Higgs Boson and Other Stuff That Will Blow Your Mind.” He also produces a series of science education videos. Follow him on Facebook. The opinions expressed in this commentary are solely his. View more opinion articles on CNN.

CNN —  

Of all of the crazy sounding things in the pantheon of modern physics, it’s hard to beat a black hole. Generally speaking, black holes are the burned-out hulks of long dead stars, with a strong enough gravitational field that not even light can escape them.

The gravity near a black hole is so strong that it warps the very fabric of space and time. Black holes sound more like science fiction than fact, but there has been considerable indirect evidence that they exist. They are accepted by the scientific community in spite of an embarrassing admission: nobody has ever directly seen one. Well, until now.

Don Lincoln
Courtesy of Don Lincoln
Don Lincoln

Scientists have announced the first direct observation of a black hole at the center of a galaxy named M87. M87 is a supergiant elliptical galaxy in the constellation Virgo. It is one of the largest galaxies in the nearby universe. (Where “nearby” is the staggering distance of 53 million light years. Astronomers really do think big.)

Now a little bit of care is necessary to understand exactly what was done. Black holes are, well, black. By definition, they do not emit any light. So, the black hole was not observed directly. However, black holes are also surrounded by ordinary matter that is caught in the hole’s gravitational grip.

This matter, which is typically just gas of the same type that makes up our sun, orbits the black hole at very high speeds. All of that fast-moving gas gets heated up to the point where it glows and emits all sorts of forms of electromagnetic radiation, from heat to light to radio waves. Intervening gas blocks the visible heat and light, so astronomers look for the radio waves.

You’d think that astronomers would announce that they detected this halo of radio waves surrounding the hole, and that is part of the story. However, it’s more complicated than that. Because of the very strong gravity near the black hole, some of the light and radio waves are captured by it and don’t escape. The result is that a black hole looks like a ring of light, with a shadow in the middle. Essentially, from a distance, the picture astronomers released of the M87 black hole looks like a coffee ring left on a piece of paper, albeit a colored one.

Since the astronomers used radio waves to see the black hole, the colors aren’t what you would see with your eye. But they do have meaning. What we are seeing is the gas surrounding the black hole. One side is bright and one is dim because the black hole is spinning. The yellow shows the side of the black hole spinning toward us and the reddish side is spinning away.

Aside from the difficulties associated with seeing something that is perfectly black, another difficulty is their size. Ordinary black holes, which have a mass the few times as big as our Sun, are only about as big as the city of Chicago. Combined with their great distances, they are simply too small to see with modern technology. Seeing the closest known black hole is as difficult as a telescope in New York City seeing a single molecule in Los Angeles. This is well beyond current technical capabilities.

Luckily, the center of nearly all galaxies contain an enormous black hole. For example, the one in the center of our Milky Way galaxy has the mass of about 4 million times that of our sun with a radius about 30 times that of the sun.

However, the black hole at the center of M87 is truly gigantic. Its mass is about 7 billion times the mass of our sun. And its dimensions are huge as black holes go. It is a sphere with a radius about 130 times that of the Earth’s orbit or about three times bigger than the average orbit of Pluto.

That sounds large, but the distance to M87 is so huge that the black hole at the center of that galaxy subtends a tiny angle. It is unbelievably small – it’s equivalent to the width of a line drawn by a sharpened pencil seen from the distance separating New York and Los Angeles, a task that is possible if scientists use an incredibly clever technique that uses the entire Earth as a telescope. And, luckily, the shadow cast by the black hole is about 2.5 times wider than the hole itself.

In 2006, an international consortium of astronomers formed a group called the Event Horizon Telescope. The name is misleading, as their equipment isn’t a telescope in the way we ordinarily think of it. Instead, the equipment they use is called a radio telescope, which is just an ultra-sensitive radio antenna.

And another level of confusion is that the group didn’t employ a single antenna. Instead what they did was to tie together a web of radio telescopes spread across the entire planet. The reason they did that is simple. How small an object a telescope can see depends crucially on the size of the telescope. The bigger the telescope, the smaller objects it can resolve.

A world-class radio telescope is only a few hundred feet across. However, by tying together a worldwide network of radio receivers, astronomers can effectively make a telescope the size of the Earth – essentially a radio telescope about 8,000 miles wide. And by using ultra-precise atomic clocks to synchronize the observations made from around the world, astronomers were able to resolve the shadow of the black hole at the center of the M87galaxy.

Get our free weekly newsletter

Science is all about pushing the limits – studying what was once impossible to do. And, being perfectly black, tiny and very distant, black holes certainly qualify. Yet black holes are a key laboratory for testing Einstein’s theory of relativity, which is our best theory of gravity. Because of this, scientists have indirectly studied them for decades, from observing their effect on nearby stars, to seeing how they heat up giant clouds of gas, to detecting how their motion sends ripples through space and time.

But seeing one directly is a new thing and a huge advance in our ability to understand the behavior of matter under the strongest gravitational forces imaginable. And it’s important to note that this work wouldn’t be possible without generous support from taxpayers and science funding agencies across the world, including the National Science Foundation here in the United States. (Disclosure: Fermilab colleagues of mine are collaborators on this project and are funded by the US Department of Energy Office of Science.)

We should all take a bit of pride in our individual role in making possible this breathtaking scientific observation. In the next weeks and months, we’re sure to learn even more.