Unbeknownst to many, the black holes we’ve been seeing in books are not actual images but are instead just visual representations of the real thing.
This is because it is nearly impossible to photograph a black hole. For one, they are too far away to be seen by the naked eye. More fundamentally, the center of a black hole is too dark, not to mention that its gravity is too great that light itself is easily swallowed into its maw.
Despite the strangely endearing name, the phrase “black hole” is perhaps somewhat misleading. https://t.co/LyOyy5rpai
— The Wire (@thewire_in) February 14, 2017
The fact that scientists haven’t been able to snap actual photos or videos of black holes has even made some people question their very existence. But make no mistake, researchers know they’re out there, thanks to the consistency of their calculations derived from Albert E. Einstein’s theory of relativity.
But now researchers may finally be able to photograph or capture an actual image of a black hole, courtesy of a new state-of-the-art telescope called the Event Horizon Telescope Array.
— RT America (@RT_America) February 17, 2017
As previously reported by Science Alert, the Event Horizon Telescope Array uses a series of radio receivers installed across different continents on Earth, including the South Pole, Hawaii, the Americas, and the French Alps.
The researchers have their sights on producing the first actual photograph of a black hole, specifically the one located at the center of our galaxy — Sagittarius A.
By using very long baseline array interferometry, each radio receiver from the Event Horizon Telescope can detect radio waves emitted by a particular object in space. One radio receiver isn’t nearly enough to produce an actual image of Sagittarius A because while this particular black hole is 4 million times larger than the Sun, it is also 26,000 light-years away from Earth.
But using a network of radio receivers located in different locations on Earth, the Event Horizon Telescope can produce enough resolution (approximately 50 microarcseconds) to deliver a clearer image of the black hole.
The telescope will aim particularly for the event horizon surrounding Sagittarius A, but there will be enough resolution to see the black hole itself.
The Event Horizon Telescope will be activated between April 5 and 14, but researchers won’t be able to release the black hole photos until the end of the year or early 2018.
As is the case with most discoveries that have something to do with how the universe works, the validity of Einstein’s theory of relativity will again be put to the test.
Using Einstein’s own theory, researchers predict that they’ll see a crescent of light around the center of the black hole rather than a ring on account of the Doppler effect, which posits that the material moving closer to Earth should appear much brighter.
“Hopefully, it will look like a crescent – it won’t look like a ring,” team member Feryal Özel said in a press conference last year. “The rest of the ring will also emit, but what you will brightly pick up is a crescent.”
Using the theory of general relativity, researchers can predict the size of the actual shadow cast by the black hole. If the actual image captured by the Event Horizon Telescope produces different results, then a shake-up in the world of physics is to be expected. Furthermore, researchers may once again face the necessity of testing the validity of Einstein’s theory of general relativity if that happens.
“We know exactly what general relativity predicts for that size,” said Özel. “Get to the edge of a black hole, and the general relativity tests you can perform are qualitatively and quantitatively different.”
Project leader Sheperd Doeleman from the Harvard-Smithsonian Centre for Astrophysics told Jonathan Amos at the BBC a couple of days ago that he won’t be surprised if the results they got are different from what they predicted.
“As I’ve said before, it’s never a good idea to bet against Einstein, but if we did see something that was very different from what we expect we would have to reassess the theory of gravity,” he said.
“I don’t expect that is going to happen, but anything could happen and that’s the beauty of it,” he added.
[Featured Image by vchal/Thinkstock]