The Cartwheel Galaxy from Hubble
From NASA’s Astronomy Picture of the Day
To some, it looks like
the wheel of a cart.
In fact, because of its
outward oval appearance, the presence of a central galaxy,
and their connection with what looks like the spokes of a wheel, the galaxy on
the right is known as the Cartwheel Galaxy.
To others, however, it
looks like a complicated
interaction between galaxies awaiting explanation.
Along with the two
galaxies on the left, the
Cartwheel is part of a group of galaxies about
400 million light years away in the constellation Sculptor.
The large galaxy's rim
spans over 100,000 light
years and is composed of star forming regions filled with extremely
bright and massive stars.
Pictured, the
Cartwheel's ring-like shape is the result of gravitational disruption caused by
a smaller galaxy passing through a large one, compressing the interstellar gas
and dust and causing a star
formation wave to move out like a ripple across the
surface of a pond.
Free Download: APOD 2017
Calendar: NASA Images