Explanation:
The first identified compact galaxy group,
Stephan's Quintet is featured in
this stunning image from the
newly upgraded Hubble Space Telescope.
About 300 million light-years away, only four galaxies of the group
are actually locked in a cosmic dance of repeated close encounters.
The odd man out is easy to spot, though.
The four interacting
galaxies (NGC 7319, 7318A, 7318B, and 7317)
have an overall yellowish cast
and tend to have distorted
loops and tails, grown under the
influence of disruptive gravitational tides.
But the bluish galaxy at the upper left (NGC 7320)
is much closer than the others.
A mere 40 million light-years distant, it isn't part of the
interacting group.
In fact, individual stars in the foreground galaxy can be seen in
the sharp Hubble image, hinting that it is much closer than
the others.
Stephan's Quintet lies within the boundaries of the high flying
constellation
Pegasus.
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