Our planet is unique for its ability to sustain abundant life. From studies of the rock record, scientists believe life had already emerged on Earth at least 3.5 billion years ago and probably much ...

Musk shared his hopes of dying on Mars, rehashed his futuristic vision for humanity, and joked about political tensions over ...

Astronomers have long searched for life within a rather narrow ring around a star, the "habitable zone," where a planet should be neither too hot nor too cold for liquid water. A new study argues that ...