Sharmila Kuthunur

For decades, humanity has searched for signs of alien life, but many have been disproven or remain inconclusive.

Despite its timeless appearance, the moon has not always been in Earth's orbit, and scientists continue to investigate its true age.

The moon is scattered with buggies, memorabilia and even human waste that astronauts left behind—some intentionally, others out of necessity—during the Apollo era.

Here is the origin story of Earth—the only place we know life to exist.

Early in its existence, massive asteroids smashed into Earth with lasting consequences for our planet’s geology and life.

Global cooperation, starting in the late 1980s, helped heal Earth’s damaged ozone layer and steer it toward recovery.