Yes, this is a real picture. More accurately, it’s 165 pictures pasted together from NASA’s Cassini spacecraft’s flyby of Saturn as the planet between the probe and the sun. From this unique vantage point, the contrast of light and shadow enabled astronomers to discern new bands of ice and dust — perhaps the remnants [...]

“The answer is rooted in the fact that our planet is a ‘living’ planet, which is still cooling,” says Laurel Goodwin, professor of geology at UW-Madison. She describes Earth as a series of shells, like a peanut M&M. “The candy shell is the crust, on which we live. The chocolate beneath is the mantle, and [...]

Losing count: New study finds object larger than Pluto in the distant solar system. Do we now have 10 planets — or 8?

The discovery of a planet that could resemble Jupiter in its size and orbit is focusing attention on this ageless question: are we alone in the universe?