The first time the Earth cooled and separated into rock and metal layers was early in the solar system’s history, so lots of hafnium was present in the Earth’s rocky layer because it hadn’t had time ...

astronaut Bill Anders. At one point in Apollo 8's lunar orbit, the Earth came into view over the moon's horizon. The crew reacted with astonishment to the beautiful sight, snapping photographs ...

The European Space Agency's Hera asteroid mission has beamed back its first images from space, capturing a stunning view of ...