NGC 7318

NGC 7318
HGC 92. 8-micrometre infrared light = red, H-alpha = green, visible red light = blue
Observation data (J2000 epoch)
Constellation	Pegasus
Right ascension	22h 35m 56.7s / 22h 35m 58.4s
Declination	+33° 57′ 56″ / +33° 57′ 57″
Redshift	6630 ± 23 / 5774 ± 24 km/s
Distance	300 Mly
Apparent magnitude (V)	14.4 / 13.9
Characteristics
Type	E2 pec / SB(s)bc pec
Apparent size (V)	0′.9 × 0′.9 / 1′.9 × 1′.2
Notable features	Colliding galaxies
Other designations
NGC 7318A / 7318B UGC 12099 / 12100 Arp 319 PGC 69260 / 69263 HCG 92D / 92B
References:
See also: Galaxy, List of galaxies

NGC 7318 (also known as UGC 12099/UGC 12100 or HCG 92d/b) are a pair of colliding galaxies about 300 million light-years from Earth. They appear in the Constellation Pegasus and are members of the Stephan's Quintet.

The Spitzer Space Telescope revealed the presence of a huge intergalactic shock wave, shown by a green arc produced by one galaxy falling into another at millions of kilometers per hour. As NGC 7318B collides with NGC 7318A, gas spread throughout the cluster, atoms of hydrogen are heated in the shock wave, producing the green glow. The molecular hydrogen visible in the collision is one of the most turbulent forms known. This phenomenon was discovered by an international team of scientists of the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg. This collision can help provide a view into what happened in the early universe, around 10 billion years ago.

Coordinates: 22^h 35^m 56.7^s, +33° 57′ 56″