Ally Shirman | firstname.lastname@example.org | April 22, 2019
Unless you live under a rock, you’ve probably seen the image of a black hole circling around the Internet. But you still wonder: How did scientists actually get an image of a thing that’s supposed to suck up light? And why is it so blurry? How come there hasn’t already been a photo?
Up until a week ago, humanity only had speculations and theories of what black holes could look like. Now we have the first ever image of one, specifically a black hole in the galaxy Messier 87, which is located 55 million light years away.
“We have seen what we thought was unseeable,” says Shep Doeleman, the director the Event Horizon Telescope (EHT) project and astrophysicist at the Harvard-Smithsonian Center for Astrophysics. It’s all thanks to a group of over 200 scientists from around the world who worked together gathering data since April of 2017 from the EHT.
Although most have heard the news, many d.tech students are still confused about how it happened, and why it is significant. Here are the answers to some of the questions that were asked:
First off, what exactly is a black hole?
According to NASA, a black hole is “an extremely dense object from which no light can escape.” The reason that nothing can escape once it reaches the black hole’s “event horizon” (or basically its point of no return) is because of its extremely strong gravitational pull.
If the black hole is so far away, with light being sucked into the black hole, “How did these scientists even manage to get a picture?” asked senior Ella Howard.
Computer scientist and member of the EHT team Katie Bouman compares taking a photo of the black hole to taking an image of an orange on the surface of the moon. “To image something this small means that we would need a telescope with a 10,000-kilometer diameter, which is not practical, because the diameter of the Earth is not even 13,000 kilometers,” Bouman says.
Since it is impractical to construct an Earth-sized telescope, eight telescopes located across the world – in Hawaii, Chile Mexico France, Spain, Antarctica, and Arizona – create “a computational telescope the size of the earth capable of resolving structure on the scale of a black hole’s event horizon,” says Bouman.
Each dish collected and recorded radio waves coming from the black hole for a week in April of 2017. From there, the data was “stored on physical hard drives and flown to a location [Manhattan] where researchers combined them into one aggregate image.” says Dan Robitzski of futurism.com.
“How long did it take Antarctica to send their data?” Junior Anthony Guardado wondered. Like the rest of the telescopes’ data, physical shipping was involved, so the Antarctic station was not able to send their information until a few months after the winter season passed.
Bouman developed an algorithm in 2016 to handle all the data once collected, which detects “the extremely slight differences between each satellite’s captured radio waves, allowing supercomputers to turn them into a visual image,” says David Grossman from Popular Mechanics.
Why is the photo blurry?
Remember that the picture of the black hole isn’t an actual photograph, but rather a compilation of data. Right now, we are at the highest resolution achievable. “The current image was taken with a network of telescopes that could capture a wavelength as small as one millimeter,” explains Robitzski. The goal is to get that down to 0.87 millimeters, which would sharpen future images by 13 percent. Additionally, a number of telescopes have already joined the EHT network since the M87 data was collected, so future images of the black hole will be higher quality, as there is more data.
“But what does this picture mean for science?” ask junior Jacob Cohen and Spanish teacher and Concurrent Enrollment Coordinator Lilia Pineda.
This image proves Albert Einstein’s theory of general relativity, which said under specific circumstances, the bright event horizon would create an outline for the dark shadow of the black hole. “The shadow exists, is nearly circular and the inferred mass matches estimates due to the dynamics of stars 100,000 times farther away,” EHT team member Avery Broderick says.
M87’s black hole is about 6.5 billion times that of our sun, and because of this large mass, “black holes warp spacetime, heating the dust and gas around them to extreme temperatures,” according to the National Science Foundation. This is why the event horizon has an orange glow.
Howard also asks “Can I visit the black hole?”
She and anyone else wondering this can try, though you won’t get very far before you die of old age. 55 million light years is quite the trek. But even if you did make it, you’d be sucked in with everything else around you too. Doesn’t sound too fun.
Here are some links that have more information about the image of the black hole: