Blue supergiants are a rare type of star that is vastly larger and more luminous than the Sun. They can have 16-40 times the mass of the Sun and put out 10,000 times more radiation. Only a tiny fraction of the most massive stars should become blue supergiants, yet they're more common in the Universe than they should be. A new study has shown that merging stars can account for the discrepancy, turning two smaller stars into a single blue supergiant.

If dark matter is a particle, it's possible that it could self-annihilate, becoming normal matter and releasing gamma radiation. Dwarf galaxies are the best objects to search for this radiation because they're small, rich in dark matter, and don't have other phenomena that could contaminate the view. A new survey examined 50 dwarf galaxies orbiting the Milky Way and saw a faint hint of gamma radiation that could be coming from dark matter annihilation.