Planetary scientists recently simulated an alternate version of our solar system: one with a super-Earth causing climate chaos on Earth, Mars and Venus. If our solar system had a super-Earth, it's ...

Whether it's robotic rovers heading to Mars or, one day, a crew of astronauts, a round-trip journey is an incredibly long one ...

Earth's climate has swung between ice ages and warmer periods for millions of years, driven by subtle changes in our planet's orbit and axial tilt. These variations, known as Milankovitch cycles, ...

A newly identified planet candidate, HD 137010 b, looks strikingly Earth-like in size and orbit — but it may be colder than Mars due to its dimmer star. If it has a thick enough atmosphere, though, ...