Contents

09 April 2021
Vol 372, Issue 6538

About The Cover

Cover image expansion

COVER In this artist's conception, plasma erupts from a magnetar, a neutron star with a magnetic field a trillion times stronger than that of a refrigerator magnet. Starquakes in the crust unleash the plasma, which escapes near the poles. The plasma generates a beam of gamma rays, which astronomers can detect on Earth. A handful of these gamma ray flares are confirming this picture of magnetar behavior and suggest that the objects may be relatively common. See page 120.
Image: NASA's Goddard Space Flight Center/Chris Smith (USRA/GESTAR)