Explanation:
In this stunning cosmic vista,
galaxy M81 is on the left surrounded by blue spiral arms.
On the right marked by massive gas and dust clouds,
is M82.
These two mammoth galaxies have been locked in
gravitational combat
for the past billion years.
The gravity from each galaxy
dramatically affects the
other during each hundred million-year pass.
Last go-round, M82's gravity likely raised
density waves rippling around M81, resulting in the richness of
M81's
spiral arms.
But M81 left
M82 with
violent star forming regions and
colliding gas clouds so energetic the galaxy
glows
in X-rays.
In a few billion years only one galaxy
will remain.
