Atom & Cosmos

Getting to supernova
White dwarf stars often don’t waltz together when they die. A new survey of 41 “Type Ia” supernovas, the explosions these dwarfs die in when they suck too much material off another star, found sodium gas flowing away from many of the explosions. But white dwarfs are mostly made of carbon and oxygen, so the sodium gas was probably thrown off by an ordinary or giant star. That suggests that the dwarfs weren’t eating their own kind. Knowing how Type Ia supernovas form is important because astronomers use their brightness to help measure cosmic distances. An international team of researchers reports the discovery in the Aug. 12 Science. —Alexandra Witze

Sunspots rising
Magnetic fields lurking deep beneath the sun’s surface could signal the imminent emergence of sunspots. Using the Solar and Heliospheric Observatory satellite, scientists have spotted such fields, much stronger than models had predicted, up to 65,000 kilometers below the surface. Over the course of a day or two, the magnetic disturbances rise upward and eventually trigger the formation of sunspots. Knowing sunspots are coming could help people better prepare for telecommunications and other outages caused by space weather, Stathis Ilonidis of Stanford University and colleagues write in the Aug. 19 Science. —Alexandra Witze