In April last year, an international collaboration attempted to do something humans have never done before: take an image of Sagittarius A*, the supermassive black hole at the center of the Milky Way. The final shipment of data was received by the collaboration last month and they have now begun analyzing it in full, meaning we may soon have the first ever image of a black hole.
It might seem weird to have such wide time gap between observation and analysis but there’s a very interesting reason. To have such high precision image, astronomers had to use a technique known as baseline interferometry, where radio telescopes that are very far from each other are linked up to make a virtual telescope as wide as their distance.
The Event Horizon Telescope, as it is called, used telescopes from all over the world including Antarctica, where they had to wait for weather conditions to be suitable to ship the hard-drive with the data to MIT's Haystack Observatory. The observations, which were received on December 13, were also shipped to the Max Planck Institute for Astronomy, in Germany. Astronomers in both locations will analyze it.
In a press release last month, the team explained that it would take about three weeks to complete the comparison of the two team's recordings after which the final analysis of the observations can truly begin. The data could deliver new insight into the quantum mechanics versus relativity debate. Black holes are one of the subject areas where the two theories struggle to play together.
In the meantime, we'll have to wait and see. Hopefully, the observations have been successful and soon we will have an image of the event horizon of Sagittarius A*, the edge of the black hole itself. Beyond it, the gravity is so intense that not even light can escape.
Sagittarius A* weighs 4 million Suns, and is "just" 44 million kilometers (27 million miles) in diameter. Being 26,000 light-years away from Earth gives it the apparent size in the sky similar to looking at a CD on the surface of the Moon from Earth. This is why the researchers needed a telescope as wide as the Earth to see it.