We may receive a commission on purchases made from links. Are we alone in the universe? It's a huge question with no easy answer. And, following on from that, if we aren't alone, what would beings ...

David Bowie as Thomas Jerome Newton in 'The Man Who Fell to Earth'; a Xenomorph in 'Aliens'; Scarlett Johansson as the Female in 'Under the Skin' A casual viewer might assume that if you've seen one ...