Astronomers have discovered an Earth-size planet orbiting a red dwarf star, making just the second planetary system seen around one of these tiny, cool, dim, but common, stars.

In ancient times, planet Venus was often thought to be two different stars, the evening star and the morning star — that is, the ones that first appeared at sunset and sunrise.

NASA’s planet-hunting telescope discovered an exoplanet in the habitable zone of a nearby star. It’s one of four known planets about 100 light-years away.

Astronomers have discovered an Earth-size planet orbiting an ultracool red dwarf star similar in size to Jupiter. The red dwarf, located some 55 light-years away, is 100 times less bright than the sun ...

There’s no real “dark side” of the moon, but the far side, which faces away from Earth, is different from the near side we see every day. Samples could reveal why.