Big Bang, conceptual image. Computer illustration representing the origin of the universe. The term Big Bang describes the initial expansion of all the matter in the universe from an infinitely compact state 13.7 billion years ago. The initial condit...

Artwork conceptualising the expanding and accelerating Universe. Since the 1990s, astronomers have known that the Universe is not only expanding, but that the rate of expansion itself is accelerating. This is postulated to occur due to a mysterious d...