 A Dwarf Galaxy Ripped Apart
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May 29, 2003 — A team of international scientists on Thursday revealed that they had discovered the tiniest galaxies in the universe, so small they were previously mistaken for stars.
University of Queensland astrophysicist Michael Drinkwater led a team of eight researchers from Australia, Britain, the United States and Germany who discovered the celestial bodies, dubbed ultra-compact dwarfs or UCDs.
"We discovered a brand new type of galaxy that is smaller than any type of galaxy found before," Drinkwater told Australian Associated Press. "Previously, they were ignored for about 30 years as nearby stars in our own galaxy, they just look the same."
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The UCDs were discovered using the Anglo-Australian Telescope in New South Wales and confirmed by measurements from the Hubble Space Telescope and the Very Large Telescope in Chile.
Drinkwater said the seven UCDs his team found each contained only about 10 million stars, while the Milky Way had about 10 billion.
What previous astronomers had assumed to be relatively close stars actually turned out to be UCDs 60 million light-years away, nestled among 300 other galaxies in an area of the universe known as the Fornax Cluster.
Astrophysicists believe the UCDs were originally larger, but lost portions of their mass to the gravitational pull of larger galaxies.
"Big groups of galaxies which go past too close to giant galaxies like our own Milky Way actually get ripped apart from the gravity of the big galaxy," Drinkwater said. "What is left is a tiny core all on its own after the surrounding stars have been ripped off."
Scientists now hope to explore other areas of the universe for more UCDs.
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