Anti-particle – Super Facts

Superfact 142: Matter and anti-matter annihilate upon contact releasing enormous amounts of energy. One gram of anti-matter yields 43 kilotons of energy which is nearly three times the yield of the Hiroshima atomic bomb (15 kilotons). Whenever an interaction creates a matter particle its antimatter counterpart is also created, leading to the mystery of why anything exists at all.

A gigantic explosion resembling a large nuclear bomb near a city. A tiny amount of matter and anti-matter annihilating could cause this. — One gram of matter and anti-matter meeting will cause an explosion three times as powerful as the Hiroshima bomb. Tiny amounts of anti-matter could cause explosions much larger than large nuclear weapons.

Anti-matter was predicted in 1928 by the physicist Paul Dirac when he combined quantum mechanics with Albert Einstein’s special theory of relativity. A few years later (1932) the anti-particle of the electron, called the positron was discovered. Since then, many anti-particles have been found. For example, scientists have also created anti-protons and anti-atoms, including anti-hydrogen atoms with an anti-proton in the middle with a positron instead of an electron orbiting the anti-proton. Using the particle accelerator at CERN physicist are now able to create thousands of anti-matter atoms in a matter of hours (pun intended). Anti-matter exists, it is all around us, and it falls down in a gravity field (created by matter), just like matter.

When an electron and a positron meet, or another particle and anti-particle meet, they annihilate in a large burst of energy. The particles will turn into photons (light particles). The energy released is determined by Einstein’s formula for energy and mass equivalency E = mc². This is why one tiny gram of matter and anti-matter can result in an explosion much larger than the 4.5 ton Hiroshima nuclear bomb. An anti-matter bomb, or anti-matter beam, would be the ultimate weapon of mass destruction.

The E = mc2 formula — Mass is energy and vice versa, a direct result of the way time and space are related. Stock Photo ID: 2163111377 by Aree_S

The pictures show a positron and an electron merging in an explosion with a wavelike photon emerging on the right. — Annihilation of a positron (at the top left) and an electron (bottom left) with the release of energy and gamma quanta Shutterstock asset id: 2200151693 by Sergey Merkulov

The picture depicts a hydrogen atom on the left and an anti-hydrogen atom on the right. — Matter and Antimatter in Modern Physics Shutterstock asset id: 2774510837 by Dream01

The facts that anti-matter exist in the first place, that particles and anti-particles annihilate so extremely violently, as well as other mysteries surrounding anti-matter, such as why there seems to be more matter than anti-matter when they are always created in equal amounts, constitute a super fact (or a few). It is a mind-blowing and important fact.

What is Anti-Matter ?

Anti-matter or anti-particles are often described as particles with the opposite charge of its matter counterpart. For example, an electron and a positron have the same mass, spin, and lifespan (immortal), but their charge is the opposite. A muon and an anti-muon have the same mass (206.77 times the mass of an electron), spin, and lifespan (2.2 microseconds), but their charge is the opposite.

However, it is more than that. Anti-particles are particles for which all external quantum numbers, such as mass, spin, and lifespan, are identical to their matter counterpart, whilst all their internal quantum numbers are reversed including electric charge, the third component of isospin, hypercharge, lepton number, baryon number, upness, downness, charmness, bottomness, and topness. Considering those two last ones are often referred to as beauty and truth, I guess we could call those quantum numbers beautiness and truthiness, but don’t quote me on that.

Perhaps, the most defining characteristics of anti-matter is that a particle will annihilate when it meets an anti-particle. An electron and an anti-muon will not annihilate. Only an electron will do that with a positron, and only a muon will do that with an anti-muon. You can say that an antiparticle is like a mirror image or mirror twin of its corresponding particle. In fact, with respect to the mathematics, an anti-particle can be treated as a normal particle moving backward in time.

Why Does Anything Exist?

As mentioned, matter than anti-matter is always created in equal amounts, which means that an equal amount of matter and anti-matter should have been created in the Big Bang, and subsequently all matter and anti-matter should have annihilated, leading to the question, “Why does anything at all exist?”. Scientists may have started to unravel that mystery.