The magnificent spiral galaxy NGC 2276 looks a bit lopsided in this Hubble Space Telescope snapshot. A bright hub of older yellowish stars normally lies directly in the center of most spiral galaxies. But the bulge in NGC 2276 looks offset to the upper left.
What’s going on?
In reality, a neighboring galaxy to the right of NGC 2276 (NGC 2300, not seen here) is gravitationally tugging on its disk of blue stars, pulling the stars on one side of the galaxy outward to distort the galaxy’s normal fried-egg appearance.
This sort of “tug-of-war” between galaxies that pass close enough to feel each other’s gravitational pull is not uncommon in the universe. But, like snowflakes, no two close encounters look exactly alike.
In addition, newborn and short-lived massive stars form a bright, blue arm along the upper left edge of NGC 2276. They trace out a lane of intense star formation. This may have been triggered by a prior collision with a dwarf galaxy. It could also be due to NGC 2276 plowing into the superheated gas that lies among galaxies in galaxy clusters. This would compress the gas to precipitate into stars, and trigger a firestorm of starbirth.
The spiral galaxy lies 120 million light-years away, in the northern constellation Cepheus.