As NASA prepared astronauts for its second mission into space, National Geographic had exclusive behind-the-scenes access for ...

Nuclear energy is a form of energy released from the nucleus, the core of atoms, made up of protons and neutrons. This source of energy can be produced in two ways: fission – when nuclei of atoms ...

Volcanoes can look like small mountains or hills. A volcano is an opening in the Earth's crust that allows magma, hot ash and gases to escape. Composite volcanoes are the most common type of volcano.