2023-04-19 10:45:49
There is a black hole that, despite its enormous mass of 20 million times that of our Sun, moves through intergalactic space much faster than the fastest of our spacecraft. At that speed, this massive star could travel from Earth to the Moon in just 14 minutes. To further surprise, the hole has left behind a 200,000 light-year-long tail of stars, twice the diameter of our Milky Way galaxy. Nothing like it had ever been seen in the universe.
Instead of gobbling up stars in front of it, the speeding black hole rams into the gas in front of it, causing clumps of gas to form, and the consequent creation of stars out of those clumps, along a narrow corridor. The black hole is moving too fast to swallow those stars or a very large amount of the gas.
The Hubble Space Telescope caught this rare trail of stars by chance. At first, it was thought to be an optical distortion caused by the camera, but Pieter van Dokkum’s team at Yale University in New Haven, Connecticut, has discovered that the trail of stars is indeed what it appears.
At one end of the trail, is the black hole. At the other end, the galaxy from which the black hole emerged. An extraordinarily bright knot of ionized oxygen is seen at the black hole end of the trail. The researchers believe that the accumulation and heating of the gas is probably due to the movement of the black hole that is charging into the gas, or it could be an accretion disk located around the black hole and emitting radiation.
The bright line is a chain of young blue stars 200,000 light-years long. A supermassive black hole is at one end of the line, specifically the bottom left end. The black hole was ejected from the galaxy at the upper right. (Photo: NASA/ESA/Pieter van Dokkum (Yale). Image processing: Joseph DePasquale (STScI))
This wandering black hole is likely the result of multiple interactions between supermassive black holes. Astronomers suspect that it all started with the merger between two galaxies around 50 million years ago. Each galaxy had a supermassive black hole at its center. The merger brought together both holes in the central area of the new galaxy formed from the union of the two. Those two black holes went on to orbit each other, forming a binary black hole system.
Then another galaxy appeared with its own central supermassive black hole. What happened next is defined by the old saying: “Two’s company and three’s a crowd.” The interactions between the three black holes gave rise to a chaotic and unstable configuration. One of the black holes stole momentum from the other two, catapulting it out of its host galaxy. The original binary system of black holes may have remained as such, or perhaps the intruder black hole replaced one of the two in the original pair, and the replaced member was the one that was ejected from the galaxy.
This unusual event occurred when the universe was about half its present age. (Fountain: NCYT de Amazings)
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