What's up in

neutron stars

astrophysics

A Cosmic Burst Repeats, Deepen­ing a Mystery

After a surprise discovery, astrophysicists are racing to understand superenergetic flashes of radio waves that sometimes beep out from distant galaxies.

astrophysics

A New Blast May Have Forged Cosmic Gold

For decades, researchers believed that violent supernovas forged gold and other heavy elements. But many now argue for a different cosmic quarry.