Why, Hello Black Hole!

April 14, 2019

For more than a hundred years, astronomers have been studying something they have never even seen: black holes. First identified in Einstein’s theory of relativity, black holes have been researched for a long time and been proven true through evidence, but only about twenty years ago did scientists find a way to photograph one. On April 10th, the first ever photo of a black hole was published, making it one of the most significant events in 2019, if not the decade!

But first … what exactly is a black hole? Simply put, it is a region in space with so much mass that nothing can escape the intense gravitational pull. A black hole is incredibly dense, which means there is an enormous amount of mass packed into a single point. Even a small black hole can pack the mass of the sun into, say, the size of one tiny city. (And in case you were wondering, there are billions and billions of black holes out there in space!)

English: Event Horizon Telescope [CC BY 4.0 (https://creativecommons.org/licenses/by/4.0)]
This amazing photo was taken of a black hole in a galaxy called M87, which is … oh … about fifty-four light years away from Earth. It took twenty years of work to finally capture photos for five days using eight telescopes. What took so long? Astronomers had to design a telescope that could ultimately take the picture, and for that, they had to understand how a black hole behaves so that they could point the telescope in the right direction at the right time. The photographed black hole is about fifty microarcseconds in the sky. And nope, it’s not visible to the human eye, even though it’s 6.5 billion times the mass of the sun. Talk about dense! Taking a photo of this black hole wasn’t exactly like pointing and clicking at a sunrise. It required a bunch of telescopes to coordinate at exactly the same time (down to a billionth of a second!), and the photo is actually of the gas swirling around the black hole. As with all good photos, weather played an important role: If there was too much water in the air near the telescopes, it might’ve distorted the photos. The telescopes were therefore placed in super dry regions like Chile and the South Pole.

What’s next for scientists? They’re working on taking better pictures to create a gallery of black hole images from across the galaxy, further illustrating what science, curiosity, and exploration can reveal!