Astronomers have made one of the most profound discoveries ever about the nature of the Universe — it is speeding up.

The Hubble Space Telescope has seen a burst of light from the most distant supernova ever detected and its brightness indicates that a mysterious force is opposing gravity and pushing galaxies away from each other.

The supernova, a stellar explosion, is at a great distance, 10 billion light-years, from Earth. It appears brighter than it should be and the only way to explain this is with the existence of a mysterious form of ‘dark energy’ that pervades the universe.