Why didn't the Big Bang produce equal amounts of matter and antimatter? © Getty Images

Why didn’t the Big Bang produce equal amounts of matter and antimatter?

This is one of the biggest mysteries about our Universe, and solving it may spark a revolution in physics.

Asked by: Adam King, Huddersfield

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This is one of the biggest mysteries about our Universe, and solving it may spark a revolution in physics. According to current theories, the Big Bang triggered the creation of pairs of particles and antiparticles, their mass coming from the intense radiation of their surroundings according to Einstein’s famous equation E = mc2. But as the Universe cooled, this process stopped – and something odd happened. The pairs of particles and antiparticles should have simply re-combined and turned back into energy. Yet while the vast majority did that, for every billion pairs that vanished, one left behind a single particle – and it was always a particle of matter.

We owe our very existence to this anomaly, but explaining it has proved extremely difficult. That’s because while antimatter and matter are radically different in many ways, the slight imbalance needed to explain today’s Universe points to a difference which is very subtle indeed.

The quest for answers has recently focused on particles called sterile neutrinos and antineutrinos. Theorists think that these may be different in ways capable of explaining why there’s more matter than antimatter. In May 2018, researchers in the US claimed to have found evidence for the existence of these particles, but this has yet to be confirmed.

What caused the Big Bang? © iStock

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