Captured accidentally by NASA’s Hubble Space Telescope, a runaway supermassive black hole leaves behind a 2,00,000-light-year-long condensed trail of newborn stars, twice the diameter of the Milky Way galaxy, in its wake. The space agency says the black hole is speeding through intergalactic space so fast that, within our solar system, it could travel from Earth to the Moon in 14 minutes.
“We’ve never seen this before,” Pieter van Dokkum, an astrophysicist at Yale University who led the study, told Live Science. The strange streak caught his eye when he analyzed images from the Hubble Space Telescope.
At first glance, the streak appeared like a “cosmic lens flare.” But after spectroscopy, van Dokkum and his team discovered that it was the tail of a black hole blasting through the galaxy.
The telescope spotted the black hole as it was capturing images of a dwarf galaxy. The cosmic lens flare appears when electrons skim along a camera detector, and the streak is a similar effect. But when van Dokkum looked closer, he noticed it was a 200,000-light-year-long star trail.
Astrophysicists believe this streak is made up of compressed gas actively forming stars. They say it results from the black hole blowing through a gas halo surrounding its home galaxy. It’s also a sign that the black hole creates new stars rather than simply eating them.
This is the first time astronomers have seen a runaway supermassive blackhole leave its host galaxy, according to the National Aeronautics and Space Administration (NASA), US. The streak was captured as the black hole traveled through space at a breakneck speed of 3.5 million miles per hour or 5.6 million kilometers per hour.
Scientists must figure out how this black hole escaped its home galaxy. They suspect it was part of a rare supermassive black hole binary destabilized by a third massive black hole.
During the merger, the third black hole might have tossed out one of the two remaining occupants, which left their partners unbalanced. This might explain how a supermassive black hole can eke out a life as a runaway.
While it isn’t a surefire explanation, it does give researchers some insight into how massive black holes form. As van Dokkum explained, these black holes are born in rare situations involving a galactic partnership that is thrown off balance.
In this case, a pair of galaxies merged about 50 million years ago, and two of their black holes whirled around each other. Then, another galaxy joined them.
The resulting merger produced two galaxies with a supermassive black hole at their centers. However, this black hole might have flung itself out into space as it formed a third black hole during the merger, causing the two to collide and destabilize the galaxies.
The two black holes flung out their entangled partners, and the third black hole became new. This might be a rare, bizarre game of galactic billiards among three massive black holes that have millions or billions of times the mass of our Sun.