By Lisa Grossman September 7, 2010
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Small galaxies, beware. A new survey caught several distant galaxies ripping up their dwarfish galactic neighbors and devouring them whole.
Astronomers have long thought this sort of intergalactic violence could be the normal way large galaxies grow. The Milky Way and the Andromeda galaxy, the two closest and best-known examples of spiral galaxies, are both known cannibals.
When a dwarf galaxy approaches a large spiral galaxy, the bigger galaxy’s extra gravitational oomph strips gas, stars and dark matter from its hapless victim. Over a few billion years, the smaller galaxy is stretched like taffy into long strips or tendrils of stars.
“Within the hierarchical framework for galaxy formation, minor merging and tidal interactions are expected to shape all large galaxies to the present day,” writes David Martínez-Delgado of the Max Planck Institute for Astronomy in Germany and colleagues in a new paper to be published in the October issue of the Astronomical Journal.
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http://www.wired.com/wiredscience/2010/09/galactic-cannibals/The best part:
All the observations were taken using backyard telescopes owned by amateur astronomers: 20-inch telescopes at Blackbird Observatory in New Mexico and Rancho del Sol in California, a 14.5-inch telescope in Moorook, South Australia, and a 6-inch telescope at New Mexico Skies.