Gravitational waves are ripples that carry energy across the universe. They were predicted to exist by Albert Einstein in 1916 as a consequence of his General Theory of Relativity. Although there is strong circumstantial evidence for their existence, gravitational waves have not been directly detected before. This is because they are minuscule - a million times smaller than an atom. Particularly exciting are "primordial" gravitational waves, which were generated in the first moments of the universes birth. These carry vital information about how the universe began. Even after reading all...