Explanation:
Why does this galaxy have so many big black holes?
No one is sure.
What is sure is that
NGC 922 is a ring galaxy created by the collision of a large and small galaxy about
300 million years ago.
Like a rock thrown into a pond, the
ancient collision sent ripples of
high density gas out from the impact point near the center that partly condensed into stars.
Pictured above is NGC 922 with its beautifully complex ring along the left side, as imaged recently by the
Hubble Space Telescope.
Observations of NGC 922 with the
Chandra X-ray Observatory, however, show several glowing X-ray knots that are likely large black holes.
The high number of massive black holes was
somewhat surprising as the gas composition in
NGC 922 -- rich in heavy elements -- should have discouraged almost anything so massive from forming.
Research is sure to continue.
NGC 922
spans about 75,000 light years, lies about 150 million light years away, and can be seen with a small telescope toward the constellation of the furnace (Fornax).
