MUNICH, Germany, Oct. 14 (UPI) — The first galaxies formed less than a billion years after the big bang and were much smaller than the giant ones we see today, European researchers say.
Somehow the average size of galaxies grew as the universe expanded, sometimes through collisions and merging to create new, larger ones.
Scientists with the European Southern Observatory have proposed another, gentler way galaxies may have increased in size, an ESO release said.
Young galaxies can also grow, they say, by sucking in cool streams of the hydrogen and helium gas that filled the early universe and using this primitive material to form new stars.
They compare the two processes to the ways a commercial company might grow, by merging with other companies or by hiring more staff. Similarly, researchers say, young small galaxies could grow in two different ways — by merging with other galaxies or by accreting, or “recruiting,” new material.
Scientists used ESO’s Very Large Telescope in Chile to study distant galaxies for signs of this process.
“The new results from the VLT are the first direct evidence that the accretion of pristine gas really happened and was enough to fuel vigorous star formation and the growth of massive galaxies in the young Universe,” team leader Giovanni Cresci says.
The discovery will have a major impact on our understanding of the evolution of the universe from the big bang to the present day, the researchers say.
Copyright 2010 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI’s prior written consent.