The Milky Way and the Seven Dwarfs

Article written: 12 Jan , 2007
Updated: 24 Mar , 2012
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Dwarf galaxies around the Milky Way. Image credit: Vasily Belokurov/SDSSThere’s no easy way to put this, our home galaxy is a killer. It’s torn up galaxies in the past, and it’s going to do it again in the future. Each galaxy we consume makes us larger. If you need evidence that this is still going on, you only need to look at the conveyor belt of dwarf galaxies orbiting the Milky Way; each of which will eventually get torn apart, its stars assimilated.

Researchers have turned up seven (or maybe eight) new dwarf galaxies orbiting the Milky Way. They’re relatively intact now, but they’ll eventually spiral into our galaxy and get torn apart by gravity. Each dwarf galaxy contains a million stars at most, and a few already appear on the edge of being torn apart.

The discovery was made by analyzing groups of stars in the Sloan Digital Sky Survey. This is a detailed database of images covering a fifth of the sky that astronomers can use for their research.

Astronomers theorize that most, or maybe all of the stars in the galactic halo and disk of the Milky Way started out in smaller dwarf galaxies, which then merged together to form the Milky Way. All these dwarf galaxies are just leftovers from that galactic feast.

Original Source: PSU News Release


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