Explanation:
Large galaxies grow by eating small ones.
Even our own galaxy practices
galactic cannibalism,
absorbing small galaxies that get too close and
are captured by
the Milky Way's gravity.
In fact, the practice is common in the universe and
illustrated by this striking pair of interacting galaxies
from the banks of the southern constellation
Eridanus
(The River).
Located over 50 million light years away,
the large, distorted spiral NGC 1532 is seen locked in a
gravitational
struggle with dwarf galaxy NGC 1531, a struggle the smaller galaxy
will eventually lose.
Seen edge-on, spiral NGC 1532 spans about 100,000 light-years.
Nicely detailed in this sharp image, the
NGC 1532/1531 pair is thought to be similar
to the well-studied system of face-on spiral and small companion
known as M51.
