GARCHING, Germany, March 14 (UPI) -- European astronomers say new observations of young galaxies' so-called feeding habits show they go from consuming interstellar gas to eating other galaxies.
During their "teenage" years -- the period from about 3 billion to 5 billion years after the big bang -- galaxies start by taking in a smooth flow of gas as the preferred snack, but later they mostly grow by cannibalizing other smaller galaxies, the researchers said.
By employing state-of-the-art instruments at the European Southern Observatory's Very Large Telescope in Chile, astronomers made 100 hours of observations of gas-rich galaxies at the early stage of their development.
"Two different ways of growing galaxies are competing: violent merging events when larger galaxies eat smaller ones, or a smoother and continuous flow of gas onto galaxies," research leader Thierry Contini said in a release from ESO's headquarters in Germany. "Both can lead to lots of new stars being created."
Smooth gas flow seems to have been a big factor in the building of galaxies in the very young universe, the researchers said, whereas mergers became more important later.
The observations also provided some new mysteries, they said.
"For me, the biggest surprise was the discovery of many galaxies with no rotation of their gas," Benoit Epinat, another member of the research team, said. "Such galaxies are not observed in the nearby Universe. None of the current theories predict these objects."
