Black holes are arguably the most mysterious objects in the universe. These infinitely dense abysses generate so much gravity that nothing in their vicinity can escape, not even light, which is why you can't see a black hole. This makes studying black holes an intense line of research because you have to work with a lot of proxies and advanced mathematics. But even if we can't see black holes, we know for sure these exist. Moreover, they're so important that they keep the galaxy together and the animation below is one of the best illustrations of its kind.
What we're looking at is a timelapse of stars' motion around a mysterious center. Specifically, this is 20 years of stellar motion condensed in 10 seconds. The invisible center of orbit is none other than Sagittarius A -- the supermassive black hole that's *four million times* more massive than the sun and which sits dead center in the Milky Way.
The star whose orbit is marked with a yellow line is called S2 and it's 15 times more massive than the sun, VOX reported. It might not look like it, but S2 is actually whizzing at 11 million miles per hour or 200 times faster than Earth orbits around the sun, as it slingshots every 16 Earth-years under the influence of Sagittarius A's massive gravity. Nothing can explain this sort of cosmic dance -- except for a black hole.
The animation above was plotted using observational data, but the one below produced by the European Southern Observatory shows a similar dance -- only this time these are all real images. You're looking at 16 years worth of observations sped up 32 million times.
All of this is amazing but you know what would be great? A picture of a black hole or, to be more precise, images of its event horizon or of the accretion disk. This might actually be possible and starting later this year to boot. As reported earlier, radio telescopes scattered across the globe will join forces making the entire planet act as a huge radio telescope dish which researchers call the Event Horizon Telescope project.
There are many challenges that await, though. For one, the radio telescopes aren't enough.
“A black hole is very, very far away and very compact,” said Katie Bouman, an MIT graduate student in electrical engineering and computer science. “It’s equivalent to taking an image of a grapefruit on the moon, but with a radio telescope. 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.”
To go around this issue, astrophysicists are using carefully planned positions for their radio dishes and use special techniques and algorithms, like interferometry. Using these 'tricks', it's possible to fill gaps by inferring information based on data gathered and position of the radio dishes.
Very exciting times await.