There’s a good chance that on Wednesday you saw the news—either on EE or somewhere else—that astronomers have successfully captured the very first image of a black hole in outer space. Now, you’ve probably seen images of black holes before, either in an astronomy article, TV show, or in film, like in my favorite movie: Interstellar. But until Wednesday, every one of those images was an artistic rendering of what a black hole might look like. Wednesday’s reveal was the real thing:
It's beautiful. It's also now my laptop's desktop background.
The image was captured by the Event Horizon Telescope (EHT)—an earth-sized virtual telescope with unprecedented sensitivity and resolution formed by linking together eight high-altitude telescopes around the world. Through the use of very-long-baseline interferometry (VLBI), EHT’s diameter essentially spanned the entire earth. It relied on the development and deployment of submillimeter dual-polarization receivers and highly stable frequency standards to enable VBLI at 230–450 GHz, higher-bandwidth VLBI backends and recorders, as well as commissioning of new submillimeter VLBI sites.
Oh, and it took a team of more than 200 researchers and the collaboration of 13 different institutes. EHT’s website lists 56 total institutions affiliated with the project.
The resulting image is of a supermassive black hole at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. It’s 55 million light-years from earth, and is 6.5-billion times bigger than the Sun. It’s hard to even try to imagine that scale.
So, what exactly are we looking at in this fuzzy-looking image? Yes, we know it’s a black hole, but its explanation makes it all the more fascinating. When I first showed the news of this announcement to EE’s managing editor, his first response was, “How can they take a picture if light cannot escape from a black hole?” It’s a very reasonable question. Through some research on my own right before and after Wednesday’s announcement, I found that the light we see in the image essentially is light that has bent around the black hole on its way to being sucked into it. So, while light can’t escape a black hole, we can still observe it being swallowed up. I could try and go further into detail, but I’d rather recommend these two videos from one of my favorite science vlog channels, Veritasium, which explain why the groundbreaking black hole image glows brighter in the lower part, and why the overall image is so fuzzy.
Part of what makes this achievement so monumental is the amount of work that went into it. Capturing and producing the image of the black hole at the center of Messier 87 was more than two decades in the making, since the inception of EHT. During a few days in April 2017, its linked telescopes were aimed at the predicted location of the black hole’s event horizon. The resulting observations produced an enormous amount of data—more than 1,000 hard drives’ worth. Those hard drives were then flown from the various observatories (including Antarctica’s Amundsen–Scott South Pole Station) to the MIT Haystack Observatory in Massachusetts, MA, and the Max Planck Institute for Radio Astronomy in Bonn, Germany. Those two sites then cross-correlated and analyzed the data on a grid computer comprised of about 800 computers connected through a 40 Gbit/s network. That giant team of researchers spent months poring over the data and searching for a signal amid the noise, and then stitched together one composite photo. Another part of what makes this photo so cool is that its roots date back to Albert Einstein’s Theory of General Relativity, published in 1915. Physicist Karl Schwarzschild and and astrophysicist Subrahmanyan Chandrasekhar used Einstein’s principles to formulate the existence of black holes, and the term first entered literature in the late 1960s—shortly before astronomers found the first evidence of one.
It also represents what can be accomplished through international collaboration. If science can achieve the impossible when looking to the cosmos, it gives me hope that perhaps this kind of collaboration can also be used help solve environmental issues here on earth.
For another cool video on what the first photo of a black hole really means, I'd recommend this:
And here's a collection of other Tweets from Wednesday surrounding the announcement:
