Why is there more matter than antimatter?
The Big Bang should have made equal parts that annihilated to nothing. The tiny imbalance is why anything exists.
What makes this fascinating
We shouldn't exist — The Big Bang should have made equal matter and antimatter, which would annihilate into pure light.
A tiny imbalance saved everything — For every billion antimatter particles there was a billion-and-one of matter — that leftover one is us.
The known asymmetry is too small — The CP-violation we've measured can't account for the imbalance; some new physics is missing.
Frequently asked questions
- Why is there more matter than antimatter?
- The Big Bang should have made equal amounts, which would have annihilated into pure energy. A tiny excess of matter survived to form everything we see — and we do not fully know why.
- What is baryon asymmetry?
- It is the technical name for this matter–antimatter imbalance. Explaining it requires the Sakharov conditions, which the known laws of physics satisfy only partly.
- Is it solved?
- No. The CP violation measured in particle physics is far too small to account for the observed asymmetry, so some unknown physics is needed.
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The nature of dark energy
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The quantum measurement problem
Why does a particle's haze of possibilities snap into one outcome when we look?
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