Scientists Capture First Picture of a Black Hole

In early April, scientists released the first picture ever taken of a black hole. To take the image, the scientists combined information from seven different telescopes, making a telescope as big as the Earth.

Over 100 years ago, Albert Einstein predicted black holes. Since then, scientists have found several ways to prove that black holes exist, but they have never been able to take a picture.

The Submillimeter Telescope (SMT), one of eight among the Event Horizon Telescope Array and one of two in the array under the management of the University of Arizona, magnifies the evening sky as the sun sets on Mount Graham near Tucson, Arizona. Photo credit: David Harvey — In early April, scientists released the first picture ever taken of a black hole. Over 100 years ago, Albert Einstein predicted black holes. But until now, scientists have never been able to take a picture.
(Source:David Harvey, via NSF.)

Black holes are so different from our everyday experiences that it can be hard to imagine them.

“Matter” means the stuff that things are made of. Matter can be spread out, or packed tightly. Tightly packed matter is “dense”. If you imagine a bowling ball compared to a Styrofoam ball of the same size, the bowling ball is much heavier because it’s denser.

When we think of gravity, we mainly think of the Earth’s gravity. But actually, everything has gravity and pulls on other things. And the larger and denser something is, the more gravity it has.

In this image of M87* taken on 11 April 2017 (a representative example of the images collected in a global 2017 EHT campaign), the shadow of a black hole is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape. — This is the first picture ever taken of a black hole. A black hole’s gravity is so strong that even light cannot escape it. The Event Horizon Telescope (EHT) project took a picture of a black hole’s shadow and the ring of light around the hole called the “event horizon”.
(Source: NSF.)

A black hole is a place where matter is so dense that the pull of its gravity is very, very strong. The gravity from a black hole is so strong that even light cannot escape it.

So the scientists involved in the Event Horizon Telescope (EHT) project couldn’t actually take a picture of a black hole. Instead, they took a picture of its shadow and the ring of light around the hole called the “event horizon”. That’s the boundary between the hole and the light that is beyond the pull of the hole’s gravity.

XKCD cartoon showing a size comparison between the M87 Black Hole and our solar system. — This cartoon helps show how huge the black hole actually is – about the size of our whole solar system – the system of planets and smaller objects that go around our sun.
(Source: XKCD.com.)

The black hole that the scientists took the picture of is massive. It’s about the size of our whole solar system – the system of planets and smaller objects that go around our sun.

But it’s also very far away. The black hole is in a far away galaxy (system of stars) called M87, about 310,000,000,000,000,000,000 miles (500,000,000,000,000,000,000 kilometers) away from Earth.

Katie Bowman was one of the 200 scientists who worked on the project. She helped create a new way to put the information from all the telescopes together. In all, about 40 women worked on the project. — Katie Bowman was one of the 200 scientists who worked on the EHT project. She helped create a new way to put the information from all the telescopes together. In all, about 40 women worked on the project.
(Source: MIT.)

So how did the scientists get that picture? First off, with lots of work. About 200 scientists in 20 countries worked on the project for almost 10 years.

They used measurements from seven different radio telescopes in different places around the world, including Hawaii, Greenland, and Antarctica. These telescopes recorded radio signals, which can be used to make an image. The scientists used special clocks to make sure the measurements were taken at exactly the same time.

The South Pole Telescope is located in Antarctica, the most extreme location of the eight telescopes in the Event Horizon Telescope Array. It is one of two in the array managed by the University of Arizona. Photo credit: Junhan Kim, The University of Arizona. — The EHT project used measurements from seven different radio telescopes in different places around the world, including Hawaii, Greenland, and Antarctica (shown above).
(Source: Junhan Kim, The University of Arizona, via NSF.)

The researchers collected so much information from these telescopes that it could fill the hard drives of about 10,000 laptops. They also had to create computer programs that could sort through and combine all of this information and turn it into a picture.

Infographic explaining process of collecting data and turning it into first image of a black hole. — The researchers collected so much information from these telescopes that it could fill the hard drives of about 10,000 laptops. They also had to create computer programs that could sort through and combine all of this information and turn it into a picture.
(Source: NSF.)

The picture is proof of Einstein’s ideas that people can see. The EHT project may also teach scientists more about gravity. And the discoveries the EHT team made in order to take the picture can now be used again in new ways.

There is another, smaller black hole in our own galaxy, the Milky Way. EHT has information for this black hole, too, but it has not yet created a picture from it.

This article has been updated to correct an error in the distance given to M87.

Sources

www.voanews.com
arstechnica.com
www.smithsonianmag.com
www.washingtonpost.com
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sixcolors.com
en.wikipedia.org