Scientists have made a key discovery about antimatter - an elusive substance that holds the key to discovering how the Universe was formed.
Antimatter is the opposite of matter, from which stars and planets are made.
Both were created in equal amounts in the Big Bang which formed our Universe. While matter is everywhere, though, its opposite is now extremely hard to find.
For years, physicists have been scrambling to discover their differences and similarities, to explain how the Universe arose.
They have now confirmed for the first time that atoms of antimatter fall downwards, the same way matter respond to gravity.