What holds together the protons and neutrons in an atom’s nucleus?

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:

• What’s the distance from a nucleus to an electron?
• What shape are subatomic particles?