Antimatter atom measured for the first time

Scientists have taken the first-ever measurement of an atom made of antimatter.

This measurement, though not very precise, represents a first step toward being able to study antimatter atoms in detail — a goal necessary for understanding why the universe is made of matter and not antimatter, its mysterious sibling.

All particles of matter are thought to have antimatter partners with the same mass but opposite charge. When these pairs meet, they annihilate each other to become pure energy.

Scientists think the universe contained equal parts of matter and antimatter just after the Big Bang, which is believed to have started everything 13.7 billion years ago. But early on, most of the matter and antimatter destroyed each other, leaving behind a slight surplus of matter that became the stars and galaxies that exist today.