This striking NASA Hubble Space Telescope image, which shows what looks like the
profile of a celestial bird, belies the fact that close encounters between
galaxies are a messy business.
This interacting galaxy duo is
collectively called Arp 142. The pair contains the disturbed, star-forming
spiral galaxy NGC 2936, along with its elliptical companion, NGC 2937 at lower
left.
Once part of a flat, spiral disk, the orbits of the galaxy's stars
have become scrambled due to gravitational tidal interactions with the other
galaxy. This warps the galaxy's orderly spiral, and interstellar gas is strewn
out into giant tails like stretched taffy.
Gas and dust drawn from the
heart of NGC 2936 becomes compressed during the encounter, which in turn
triggers star formation. These bluish knots are visible along the distorted arms
that are closest to the companion elliptical. The reddish dust, once within the
galaxy, has been thrown out of the galaxy's plane and into dark veins that are
silhouetted against the bright starlight from what is left of the nucleus and
disk.
The companion elliptical, NGC 2937, is a puffball of stars with
little gas or dust present. The stars contained within the galaxy are mostly
old, as evidenced by their reddish color. There are no blue stars that would be
evidence of recent star formation. While the orbits of this elliptical's stars
may be altered by the encounter, it's not apparent that the gravitational pull
by its neighboring galaxy is having much of an effect.
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