A newly published story at the Royal Astronomical Society states that galaxies turn to cannibalism when they get too big to keep growing on their own. It was a known fact to scientists that big galaxies like to chow down on smaller ones. When they collide, the larger galaxy gains the mass of the smaller one. As per the Monthly Notice report of Royal Astronomical Society, “All galaxies start off small and grow by collecting gas and quite efficiently turning it into stars,” Aaron Robotham, a postdoctoral researcher at the International Centre for Radio Astronomy Research and head of the study, said in a statement. “Then every now and then they get completely cannibalized by some larger galaxy.”
As galaxies grow, they get worse at making new stars. They also have stronger gravity, which helps them pull neighboring smaller galaxies into the fold. The Milky Way reached this tipping point “recently,” in cosmic terms and will now grow mostly by snacking on the little guys. It’s been a while since our neighborhood ate another one, but astronomers can still see the signs of former galaxies that we’ve digested.
Researchers looked at more than 22,000 galaxies and noticed the most massive are not very good at generating new stars, and instead grew larger by feasting on smaller galaxies, the International Centre for Radio reported. “All galaxies start off small and grow by collecting gas and quite efficiently turning it into stars,” said Aaron Robotham based at The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR) “Then every now and then they get completely [cannibalized] by some much larger galaxy.”
“If you waited a really, really, really long time that would eventually happen but by really long I mean many times the age of the universe so far,”Robotham said.
The researchers made their findings through research collected by the Anglo-Australian Telescope in New South Wales as part of the Galaxy And Mass Assembly (GAMA) survey.
I thought that galaxies are supposed to be flying away from each other due to the universe expanding!