The mysterious ‘something’ behind the accelerating expansion of the Universe

Dark energy is the term that scientists have given to the mysterious ‘something’ deemed responsible for the accelerating expansion of the Universe. However, unlike gravity, which pulls things together, physicists and cosmologists still can’t explain what dark energy really is or how it does what it does, despite the fact that it theoretically makes up a substantial part of everything. In this upbeat animation, Pedro Ferreira, professor of astrophysics at the University of Oxford, points to the scenarios that his field faces – the ‘incredibly exciting’ one and the ‘doomsday’ one – perhaps taking solace in knowing that there are only two.