NASA’s Astronomy Picture of the day
SEE IMAGE BELOW. This dance is to the death.
Along
the way, as these two large galaxies duel, a cosmic bridge of
stars, gas, and dust currently stretches over 75,000 light-years and
joins them.
The
bridge itself is strong evidence that these two immense star systems have passed close to each
other and experienced violent
tides induced by mutual gravity.
As
further evidence, the face-on spiral galaxy on the right, also known as NGC
3808A, exhibits many young blue star clusters produced in a burst of star
formation.
The
twisted edge-on spiral on the left (NGC 3808B) seems to be wrapped in the
material bridging the
galaxies and surrounded by a curious polar ring.
While
such interactions are drawn out over billions of years, repeated close passages should
ultimately result in the death of one galaxy in the sense that only one galaxy
will eventually result.
Although this
scenario does look peculiar, galactic mergers are thought to be
common, with Arp 87 representing a stage in this inevitable
process.
The prominent edge-on spiral galaxy
at the far left appears to be a more distant background galaxy and not involved
in the on-going merger.
