Atom & Cosmos

The right mix of dark matter to build a galaxy, plus Kleopatra’s twins and an electric Encaledus in this week’s news

Dark recipe for galaxies
When it comes to dark matter, the mass equivalent of 300 billion suns is the Goldilocks number — just the right amount for making a galaxy teeming with stars. A new report spotlights the role that dark matter, the invisible material that accounts for more than 80 percent of the matter in the cosmos, plays in pulling in gas and stars to form the earliest galaxies.