Stars in dwarf spheroidal galaxies behave in a way that suggests the galaxies are utterly dominated by dark matter, University of Michigan astronomers have found.
Astronomy professor Mario Mateo and post-doctoral researcher Matthew Walker measured the velocity of 6,804 stars in seven dwarf satellite galaxies of the Milky Way: Carina, Draco, Fornax, Leo I, Leo II, Sculptor and Sextans. They found that,
contrary to what Newton's law of gravity predicts, stars in these galaxies do not move slower the farther they are from their galaxy's core.
"These galaxies show a problem right from the center," Mateo said. "The velocity doesn't get smaller. It just stays the same, which is eerie."