Tag: Segue 2

UCI Scientists Size Up Universe’s Most Lightweight Dwarf Galaxy with Keck Observatory

W. M. Keck Observatory press release…

The least massive galaxy in the known universe has been measured by UC Irvine scientists, clocking in at just 1,000 or so stars with a bit of dark matter holding them together.

Milky Way Dark Matter Distribution
This image shows a standard prediction for the dark matter distribution within about 1 million light years of the Milky Way galaxy. Image credit: Garrison-Kimmel, Bullock (UCI)
The findings, made with the W. M. Keck Observatory and published today in The Astrophysical Journal, offer tantalizing clues about how iron, carbon and other elements key to human life originally formed. But the size and weight of Segue 2, as the star body is called, are its most extraordinary aspects.

“Finding a galaxy as tiny as Segue 2 is like discovering an elephant smaller than a mouse,” said UC Irvine cosmologist James Bullock, co-author of the paper. Astronomers have been searching for years for this type of dwarf galaxy, long predicted to be swarming around the Milky Way. Their inability to find any, he said, “has been a major puzzle, suggesting that perhaps our theoretical understanding of structure formation in the universe was flawed in a serious way.”

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