Everyone knows that the universe began billions of years ago with the Big Bang.

But for the past 20 years, a group of Harvard physicists have been trying to figure out why the universe still exists.

Physicists think the Big Bang produced equal amounts of both matter and anti-matter.

When the two meet, they annihilate each other in a burst of energy.

Puzzlingly, scientists see more matter than anti-matter in the universe.

A group of Harvard physicists led by Professor of Physics Gerald Gabrielse have taken the first steps towards answering this question.

They created anti-hydrogen in a lab last October, an important step toward finding out if matter and anti-matter have different properties. If encountered, these differences could explain why the universe did not explode into a burst of energy shortly after it started.

Though the riddle may be a billion years old, Gabrielse and his team are racing to solve it. A group of European physicists based in Geneva are also producing anti-matter, and the Harvard group is vying to make important discoveries in a field which it used to dominate.

But for now, both teams are waiting until a key component of their experiment can be used again.

Does Anti-Matter Matter?

Anti-matter has long fascinated physicists because it seems to be exactly like regular matter, but with certain properties exactly flipped.

For example, a normal electron has a negative charge, but an anti-matter positron has a positive charge, although it seems to be the same as an electron in every other respect.

“I don’t see any reason why we couldn’t, in principle, be made out of anti-matter,” said Gabrielse.

“It’s a fascinating question that we do not know the answer to right now,” he said. “It kind of gnaws at me a bit.”

Gabrielse and his team make their anti-matter at the European Centre for Nuclear Research (CERN) in Geneva, Switzerland.