
What holds together the protons and neutrons in an atom’s nucleus?
The rule opposites attract and likes repel has to be overcome if protons and neutrons are to stay together inside a nucleus. This is where quarks can help.
Asked by: David Kelly, Manchester
All protons are positively charged, and as a result repel each other. So the fact that atoms even exist points to a force able to overcome this repulsion.
Called the strong interaction, its origins lie in the particles lurking inside both protons and neutrons, called quarks. These possess a weird form of charge, whimsically termed ‘colour’, which glues them together inside their host particles – and also seeps out to bind the protons and neutrons together, too.
Read more:
Authors

Robert is a science writer and visiting professor of science at Aston University.
Subscription offer
Subscribe and save 50% on the shop price. Pay just £16.50 every 6 issues by Direct Debit. Receive every issue delivered direct to your door with FREE UK delivery.