Panther Media/Alamy
Is there exactly the same number of electrons as there are protons in the universe? Is that also true of Earth at any given moment?
Eric Kvaalen
Les Essarts-le-Roi, France
In most stars, hydrogen is turning into helium, and the process starts with two protons coming together to form helium-2. This usually splits back apart very quickly, but sometimes one of the protons turns into a neutron, a neutrino and a positron (a positively charged anti-electron). The positron annihilates quickly with an electron.
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