Galaxy growth examined like rings of a tree
Tuesday, November 5, 2013 - 12:00
in Astronomy & Space
Galaxies outlive trees by billions of years, making their growth impossible to see. But like biologists reading tree rings, astronomers can read the rings in a galaxy's disk to unravel its past. Using data from NASA's Wide-field Infrared Survey Explorer (WISE) and Galaxy Evolution Explorer (GALEX), scientists have acquired more evidence for the "inside-out" theory of galaxy growth, showing that bursts of star formation in central regions were followed one to two billion years later by star birth in the outer fringes.