Aug. 19 (UPI) -- Astrophysicists have found bullet-like globs of dense, cold gas that were expelled from the center of the Milky Way.
Researchers described the strange gas in a new paper, published Wednesday in the journal Nature, but the cause of their ejection remains a mystery.
Solving the mystery, authors of the new study contend, could help cosmologists better understand the evolution of galaxies like the Milky Way.
Scientists have previously spotted gas being shot from the center of faraway galaxies, but never inside the Milky Way.
"Our own galaxy is almost like a laboratory that we can actually get into and try to understand how things work by looking at them up close," lead study author Enrico Di Teodoro, astrophysicist at Johns Hopkins University, said in a news release.
Figuring out how and why the Milky Way's center is expelling cold, dense gas could help scientists better understand why galaxies eventually stop making new stars.
"Galaxies can be really good at shooting themselves in the foot," said study co-author Naomi McClure-Griffiths, professor of astrophysics at the Australian National University. "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."
Scientists suspect the ejected gas is evidence of this galactic self sabotage.
"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!" McClure-Griffiths said.
Many of the Milky Way's mysteries lie at the center of the spiral galaxy. If scientists can figure out what caused the gas to become ejected, they'll be able to get a better sense of the forces at work in the center of the Milky Way.
"The wind at the center of the Milky Way has been the topic of plenty of debate since the discovery a decade ago of the so-called Fermi Bubbles -- two giant orbs filled with hot gas and cosmic rays," McClure-Griffiths said.
The gas described in the new paper is cold and extremely dense. Cold, heavy gas is much harder to move around.
The center of the Milky Way is home to a massive black hole, capable of generating the kind of forces that could propel blobs of cold gas, but it also hosts thousands of massive stars, able to produce powerful forces themselves.
To solve the mystery of what exactly shot the gas bullets, scientists suggest additional observations and analysis are necessary.