Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

December 28, 1995

NGC 6240: When Galaxies Collide
Credit: 2.2m Telescope, La Silla, Chile, ESO, MPI, W. Keel (UA)

Explanation: Sometimes even galaxies can suffer a fatal attraction. Here gravity causes two galaxies to collide in a spectacular display of energetic gas, dust, and light. When galaxies collide it is rare that any stars in the galaxies themselves collide, or that any change will be seen in a human lifetime. Rather the structure of one or both galaxies gets slowly disrupted, while interior gas condenses to new star forming regions. Stellar motions in the centre of the NGC 6240 frenetic mix are among the highest in any stellar system. Galaxy mergers may emit energetic radiations across the electromagnetic spectrum. This galactic jumble is, in fact, extremely bright in infrared light.

Tomorrow's picture: NGC 4361: Galaxy Shaped Planetary Nebula

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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