It starts with a signal. Faint, strange, and unlike anything humanity has ever recorded. Within hours, it escalates into an event that changes the course of history as an alien arrival on Earth ...

Our species likes it cold. Homo sapiens evolved in — and still inhabits — one of Earth’s rare and fragile ice ages, periods distinguished not by an abundance of saber-toothed cats and woolly mammoths ...

NASA has discovered a new super-Earth that has a year only lasting a few hours. The exoplanet K2-141b, was found very close to its orange sun-like star, and has an orbital period of less than one ...

Exoplanets are planets outside Earth's solar system. In 1995, a gas giant named 51 Pegasi b, which orbits a star similar to Earth's sun, etched its name in history as the first exoplanet ever ...