Benefactors can be too generous. Exploding stars in a small galaxy called Leo P pumped out heavy elements with such vigour that most of them sailed off into space. "It's tough being a little galaxy," says Kristen McQuinn at the University of Texas at Austin. Not only does a dwarf galaxy's feeble gravity fail to retain debris from supernovae that explode within it, but giant galaxies such as the Milky Way can also raid the dwarf of stars and gas. Dozens of dwarf galaxies orbit the Milky Way, and all have low levels of heavy elements. But we didn't know how much of the dwarfs' poverty to attribute to our galaxy's thieving ways, or how much material simply escaped.
展开▼
