A team of international astrophysicists led by the Australian National University (ANU) have discovered the source of the antimatter.
Their study shows how most of the antimatter in the Milky Way forms.
When antimatter, which is composed of antiparticles meets particles of ordinary matter, they quickly annihilate each other to form a burst of energy in the form of gamma-rays.
Since the early 1970s, scientists have known that the inner parts of the Milky Way galaxy, is a strong source of gamma-rays. The presence of gamma-rays indicates the existence of antimatter, however it was not known where the antimatter came from.
At first, researchers ruled out other possibilities such as the supermassive black hole at the centre of the Milky Way and the still-mysterious dark matter as being the sources of the antimatter.
Now, researchers know a series of weak supernova explosions lead to a collision between two white dwarf stars.
The antimatter came from a system where two white dwarfs form a binary system and collide with each other. The smaller of the binary stars loses mass to the larger star and ends its life as a helium white dwarf, while the larger star ends as a carbon-oxygen white dwarf.
He said once they became too close the carbon-oxygen white dwarf ripped apart the companion star whose helium quickly formed a dense shell covering the bigger star, quickly leading to a thermonuclear supernova that was the source of the antimatter.