Simon Singh looks at the stories behind the discovery of five of the universe's most significant subatomic particles. 4) The Neutrino. It's the most populous particle in the universe. Millions of these subatomic particles are passing through each one of us. With no charge and virtually no mass they can penetrate vast thicknesses of matter without any interaction - indeed the sun emits huge numbers that pass through earth at the speed of light. Neutrinos are similar to the more familiar electron, with one crucial difference: neutrinos do not carry electric charge. As a result they're extremely difficult to detect . But like HG Wells' invisible man they can give themselves away by bumping into things at high energy and detectors hidden in mines are exploiting this to observe these rare interactions. But they can give themselves away by bumping into things at high energy, and detectors hidden in mines are exploiting this to see inside stars for the very first time Producer: Adrian Washbourne Producer Adrian Washbourne.