Taktika pencils used by Alexei Leonov on board Voskhod 2 (1965), and the first drawing created in space (© Museum of the Yuri Gagarin Cosmonaut Training Centre) LONDON — The first human to spacewalk ...

Sound, when emitted by a source — whether a person or a piece of equipment — propagates in all directions through space, being reflected, absorbed, transmitted, or diffracted as it encounters surfaces ...

In a new book, NASA astrobiologist Caleb Scharf says the fate of life on Earth may hinge on leaving our planet behind The multibillion-year story of life on Earth is defined by a handful of epochal ...