The existence of antimatter lies at the heart of modern physics. Both views are needed to explain the behavior of atoms, but they are incompatible without antimatter. Antimatter also is a key piece of the puzzle of how the universe was born. All versions of the Big Bang theory require that, at some point after the initial explosive birth, there had to be equal parts of matter and antimatter. Once considered strictly theoretical, antimatter has been steadily emerging into the world of reality.
Antiparticles look and behave the same as ordinary subatomic particles.
But although they have the same mass as their matter counterparts, they have the opposite electrical charge. If particles and antiparticles meet, they instantly annihilate each other, releasing a large amount of energy in the process.