When the massive collections of stars known as galaxies collide, the results are spectacular. Here's a gallery of galaxies that are interacting — sometimes to the point of completely changing each other's shapes in the most dramatic ways imaginable.
The larger galaxy of Arp 273, known as UGC 1810, has a disk that is tidally distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. Arp 273 lies in the constellation Andromeda and is roughly 300 million light-years away.
(Photo by AP/NASA)
IRAS 20351+2521, a structure of dust, gas and blue star knots in the constellation of Vulpecula, the Fox, 450 million light-years away
Arp 302, (also known as UGC 9618 or VV 340) a pair of gas-rich spiral galaxies in their early stages of interaction, 450 million light-years away from Earth.
Arp 272 (also known as NGC 6050 or IC 1179), collision of two spiral galaxies in the Hercules Galaxy Cluster, 450 million light-years away from us
Arp 256, two spiral galaxies in an early stage of interacting, 350 million light-years away
Arp 194, a group of several galaxies, along with "cosmic fountain" of stars, gas and dust that stretches over 100,000 light-years, about 600 million light-years from the Earth
NGC 1614 with two inner spiral arms, in the constellation of Eridanus, the River, about 200 million light-years away
NGC 520, a collosion between two disk galaxies that started 300 million years ago, and now it's in the middle stage of the process, about 100 million light-years away
Zw 96, located in the constellation of Delphinus, the Dolphin, about 500 million light-years away
VV 705 (or Markarian 848) with highly curved arms, in the constellation of Bootes, the Bear Watcher, approximately 550 million light-years away from Earth
Arp 240 (NGC 5257/8), two galaxies interacting with each other via a bridge of dim stars connecting the two galaxies. They're located in the constellation Virgo, approximately 300 million light-years away.
(Photo by NASA/ESA/The Hubble Heritage)
UGC 9618 (also known as VV340) in the constellation of Boötes, about 450 million light-years away from Earth
A detailed look at the center of a collision between Antennae galaxies (known formally as NGC 4038/4039)
(via Brad Whitmore/NASA)
Arp 148 (also known as the Mayall's Object) is the staggering aftermath of an encounter between two galaxies, resulting in a ring-shaped galaxy and a long-tailed companion. The collision between the two parent galaxies produced a shockwave effect that first drew matter into the center and then caused it to propagate outwards in a ring. This object is located 500 million light years away within the constellation of Ursa Major.
(Photo by NASA/ESA/Hubble)
ESO 593-8 with a feather-like galaxy crossing, 650 million light-years away from us
ESO 077-IG014 (or ESO 77-14), in the constellation of Indus, the Indian, 550 million light-years away
NGC 3256 (or AM 1025-433), the relict of a collision in the Hydra-Centaurus supercluster complex, about 175 light-years away
NGC 5331, a pair of spiral galaxies interacting with each other in the constellation Virgo, the Maiden, approximately 450 million light-years away
A composite image of the Antennae galaxies, with photos of the Chandra X-Ray Observatory, the Hubble Space Telescope and the Spitzer Space Telescope, about 45-65 light years away
Bonus: NGC 3314, two spiral galaxies located in the constellation Hydra, between 117 and 140 million light-years away from Earth. These two galaxies aren't colliding, it's only caused by the optical effect of overlapping.