We know that ancient lunar volcanos spewed lava. Gases rising from the lava might have accumulated around the moon to form a temporary atmosphere, 3 to 4 billion years ago.
Merging black holes are the sorts of catastrophic events that produce the strongest gravitational waves. Scientists just announced 5 new pairs, in the centers of distant galaxies.
Astronomers say they've found a smoking gun that rules out the idea of an energy-harvesting megastructure or Dyson sphere - built by an alien civilization - surrounding Tabby's Star.
Scientists said the solar event "lit up Mars like a light bulb." It was the biggest event of its kind so far observed by spacecraft in Mars orbit and on the surface.
Most comets become active only when near the sun. This one is active, but distant, between the orbits of Saturn and Uranus, where sunlight is 1/225th as bright as seen from Earth.
New ScienceCast video on recent results from New Horizons spacecraft data. Landslides on Charon. Possible snow on Pluto. Plus a preview of New Horizons' next target.
At a NASA symposium this week, space scientists and engineers presented an exciting new concept for a lander that would explore Pluto by "hopping" across its surface.
Astronomers assume our Milky Way galaxy is typical. They use our knowledge of it to leapfrog out to understanding the rest of the universe. But is the Milky Way typical?