For the next week and a half, astronomers from around the world are turning Earth into one huge telescope dubbed the “Event Horizon Telescope.” Eight telescopes from Hawaii to Chile, Spain to the south pole, will peer at Sagittarius A – the black hole at the center of the Milky Way galaxy.
As the telescope’s nickname suggests, the group of telescopes will gather reams of data to hopefully produce the first images of the black hole’s event horizon. The deluge of data could also help astronomers determine the black hole’s mass.
“These are the observations that will help us sort through all the wild theories about black holes. And there are many wild theories,” says astronomy research professor Gopal Narayanan at the University of Massachusetts Amherst.
“With data from this project, we will understand things about black holes that we have never understood before.”
But turning Earth into a huge telescope? Yep. It’s called Very Long Baseline Interferometry (VLBI) and creates a giant simulated telescope. The size of this simulated telescope is based on the distance between the telescopes. The further the telescopes, the bigger and better the telescope.
Invented in the 1960s, VLBI was used to take better pictures of quasars. As quasars emit radio waves, they reach telescopes across Earth at different times. Astronomers crunch all the data and create better images than if they used just one telescope.
Did You Know: Fun fact about VLBI. Because quasars don’t move in the sky, scientists can use geometry to see exactly how far the telescopes are apart when the radio waves reach each telescope. Take a ton of measurements, and you can use the data to study how tectonic plates move on Earth. Here’s a quick video from NASA describing how it works.
Each telescope will watch Sagittarius A for the next several days. The amount of data collected from these observations will be absurd. So absurd, each team of astronomers will fly the data to the MIT Haystack Observatory in Massachusetts versus sending them via the internet according to MIT News. We’re talking petabytes of data. One petabyte is 1,000 terabytes. That’ll make a Comcast customer nervous.
The Event Horizon Telescope will gather all its data between now and April 14th. Besides the black hole at the center of the Milky Way, the telescope will also take a peek at the one in the center of Messier 87. That supermassive black hole lives up to its name at about 6 billion times the mass of our sun.
Imaging the black hole is one goal. Studying the physics of accretion is another. That’s the process where a black hole’s gravity tugs on nearby matter and creates a “flattened band of matter around the event horizon called the accretion disk.”
Map of all the telescopes being used.
Astronomers are also interested in learning more about the large plasma jets coming from the black hole at the center of most galaxies.
But we’re going to have to be patient for the results. Combining all the radio data to create an image for us to see isn’t easy. It’ll take months just to prepare the data. And researchers won’t publish the first results until next year.
“At the very heart of Einstein’s general theory of relativity there is a notion that quantum mechanics and general relativity can be melded, that there is a grand, unified theory of fundamental concepts. The place to study that is at the event horizon of a black hole,” says Narayanan.
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