Mystery Of The Missing Mini-Galaxies

Something missing? (Image: NASA/ESA/STScI/AURA/A. Aloisi)

From New Scientist:

LIKE moths about a flame, thousands of tiny satellite galaxies flutter about our Milky Way. For astronomers this is a dream scenario, fitting perfectly with the established models of how our galaxy's cosmic neighbourhood should be. Unfortunately, it's a dream in more ways than one and the reality could hardly be more different.

As far as we can tell, barely 25 straggly satellites loiter forlornly around the outskirts of the Milky Way. "We see only about 1 per cent of the predicted number of satellite galaxies," says Pavel Kroupa of the University of Bonn in Germany. "It is the cleanest case in which we can see there is something badly wrong with our standard picture of the origin of galaxies."

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