Comets are diffuse balls of ice and dust orbiting the sun. They're sometimes visible in our skies. A comet's tail can stretch millions of miles across space.
Is there a North Star for Mars ... a guide star for future explorers? Not in any satisfying way. But Martian stargazers wouldn't lack for things to see!
Some October night, check out 3 of the flashiest stars in the night sky ... at least at this time of year. And here's why you see these as a flashing star.
Today, an annular solar eclipse will cross over parts of South America, the Pacific Ocean, the Atlantic Ocean, and Antarctica. Watch a livestream here.