Scientists discover giant gamma-ray bubbles in the Milky Way

Scientists believe the bubbles may have been made by a black hole.

THERE’S a chance that some time in the recent past a supermassive black hole erupted inside our galaxy.

Scientists in the US this morning announced that they have found two huge bubbles of radiation in the centre of the Milky Way, possibly created by a black hole eruption just a few million years ago.

The two mysterious bubbles of gamma-ray each span 25,000 light years, and were discovered using NASA‘s Fermi Gamma-ray Space Telescope and data from Fermi’s Large Area Telescope.

The structure, shaped like a dumbbell or perhaps a very large peanut, extend north and south of the galaxy’s plane. In the same place there is a supermassive black hole that weighs around 4 million times more than the sun.

Scientists knew there was something strange at the heart of the Milky Way as previous studies had found clues, but until now the bulbous structures were hidden by a fog of background gamma rays.
Doug Finkbeiner, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who first recognized the feature, told reporters “we were definitely looking for something,”

“Some hints of this signal had been seen before, but not convincingly.”

The bubbles contain much more energy than the gamma-ray fog, about the same amount as 100,000 exploding stars.

Researchers don’t know what caused them, but the defined shape of the bubbles suggest that a large, fast and recent release of energy was behind it.

“We don’t fully understand their nature or origin,” Mr Finkbeiner said.

Scientists believe that it may have been either the explosion of a star formation or a powerful particle jet from the Milky Way’s central black hole that was behind it.

There is no evidence that our black hole has such a jet, but given the time span there is always the possibility that it has had one before.

“In other galaxies, we see that starbursts can drive enormous gas outflows,” said David Spergel, a scientist at Princeton University in New Jersey. “Whatever the energy source behind these huge bubbles may be, it is connected to many deep questions in astrophysics.”

NASA said in a press release that scientists are conducting more analyses to better understand how the unique structure was formed.