Giant flares emitted from the surface of highly magnetized neutron stars could explain some gamma-ray flashes astronomers have caught over the past few decades.
Jupiter and Saturn's "Great Conjunction" is a noteworthy event, but on the morning of March 25, 185 BC, an even grander planetary gathering greeted Babylonian sky watchers
Astronomers have released a new, extremely detailed three-dimensional census of our Milky Way galaxy.
The subtle effect of sunlight may turn the near-Earth asteroid Apophis toward Earth in 2068 . . . but chances for impact remain small.
Gravitational-wave observatories have detected the most massive black hole merger yet, and it's challenging our ideas of black hole formation.
Radio observations have turned up evidence of a cloud of hot plasma near — or even in — the solar system. But its distance estimate is still up for debate.
The latest data release from a survey of 31 million galaxies reveals that our universe is even smoother than we thought it was.
One of the most luminous supernovae ever discovered provides evidence that such extremely bright explosions require exotic sources.
A 2008 image captured a stunning double loop of stars around an edge-on galaxy. Now, astronomers are questioning whether one of those loops exist.