June 9, 1997: The Hubble telescope's infrared camera has uncovered a collision between two spiral galaxies in the heart of the peculiar galaxy called Arp 220. The collision has provided the spark for a burst of star formation.
Hubble's infrared vision has captured bright knots of stars forming in the heart of Arp 220. The bright, crescent, moon-shaped object is a remnant core of one of the colliding galaxies. The core is a cluster of 1 billion stars. The core's half-moon shape suggests that its bottom half is obscured by a disk of dust about 300 light-years across. This disk is embedded in the core and may be swirling around a black hole. The core of the other colliding galaxy is the bright round object to the left of the crescent, moon-shaped object. Both cores are about 1,200 light-years apart and are orbiting each other.