New distances to two dwarf galaxies with unusually spread-out stars support the idea that these galaxies have little to no dark matter.
A Tibetan cosmic-ray observatory has discovered high-energy particle accelerators within our galaxy.
Much of the solar system’s interplanetary dust — seen as zodiacal light from Earth — might come from Mars.
A single high-energy neutrino may shed light on a star being swallowed by a supermassive black hole some 690 million light-years away.
Astronomers have discovered a cluster of galaxies coming together just 770 million years after the Big Bang.
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.