A computer simulation shows stars in a galaxy like our Milky Way on the left and the same region’s dark matter on the right. Image via Andrew Wetzel/ Carnegie Science.

Astronomers have been pondering the puzzle of dwarf galaxies for some years. Standard cosmology predicts there should be hundreds of dwarf galaxies in orbit around galaxies like our Milky Way galaxy. But, so far, astronomers know of only about 50 small galaxies within about 1.4 million light-years of the Milky Way, and it’s possible they’re not all true Milky Way satellites. So where are the rest of the dwarf galaxies? Astronomical theorist Andrew Wetzel, who has a joint appointment with Carnegie Observatories and Caltech, thinks they might not need to exist, after all.
Wetzel ran a highly detailed computer simulation of a galaxy like our Milky Way. His statement from CarnegieScience said it makes:
… the most-accurate predictions to date about the dwarf galaxies in the Milky Way’s neighborhood. Wetzel achieved this by running the highest-resolution and most-detailed simulation ever of a galaxy like our Milky Way.