Two giant blobs made up of a swirling complex of gases and cosmic rays sit centered above and below the plane of the Milky Way.
These two “Fermi bubbles,” first spotted a decade ago, are clustered relatively close to the supermassive black hole lurking at the center of our galaxy called Sagittarius A*, a highly turbulent and energetic area of our galaxy.
Now, astronomers have observed that these two bubbles are spitting out clusters of cold molecular gas “like bullets,” according to new research. And they have no idea how.
“Galaxies can be really good at shooting themselves in the foot,” Naomi McClure-Griffiths from The Australian National University, co-author of a paper about the research published in Nature on Wednesday, said in a statement. “When you drive out a lot of mass, you’re losing some of the material that could be used to form stars, and if you lose enough of it, the galaxy can’t form stars at all anymore.”
“So, to be able to see hints of the Milky Way losing this star forming gas is kind of exciting — it makes you wonder what’s going to happen next!” she added.
The team used the Atacama Pathfinder Experiment, a 12-meter telescope scanning for infrared and radio waves, at the European Southern Observatory (ESO) in Chile for their research.
McClure-Griffiths and her team are still puzzled as to what may be causing the unusual effect or if Sagittarius A* has anything to do with it.
“We don’t know how either the black hole or the star formation can produce this phenomenon,” lead author Enrico Di Teodoro from Johns Hopkins University said.
While the effect has been observed in other galaxies, our galaxy isn’t spewing out new stars at nearly the same rate.
“With external galaxies you get much more massive black holes, star formation activity is higher, it makes it easier for the galaxy to expel material,” Di Teodoro said.
There are two possible explanations, neither of which the team is willing to fully subscribe to: either a burst of star formation produced several supernovae and generated strong winds — or Sagittarius A* accreted matter and launched it out of two jets from either poles.
For now, the true cause is still a mystery.
“We’re still looking for the smoking gun, but it gets more complicated the more we learn about it,” Di Teodoro added.
READ MORE: Mystery Gas Has Been Detected Shooting ‘Like Bullets’ From Our Galactic Centre [Science Alert]
More on space bullets: A “Dense Bullet of Something” Blasted Holes in the Milky Way