A close encounter with the large galaxy M81 (lower galaxy in optical
image at left) in the last 10 million years is thought to have triggered
the burst of star formation in M82 (upper galaxy in optical image
at left). For this reason, M82 is called a starburst galaxy. The stars
do not form all at once, but over a period of a few millions years.
The rate at which stars are forming in M82 is fifty to a hundred times
that for a normal galaxy its size.
| M. Weiland,
Interest Group, U.Constance