One peculiarity of massless particles is that they have to travel at the speed of light.

ECONOMIST: Cosmology

Dr Koshiba's second detector showed that neutrinos, previously believed to be massless, actually have a small mass.

ECONOMIST: The 2002 Nobel prizes: Windows on the world | The

If neutrinos were truly massless, the standard model would predict that their flavours would be fixed for ever.

ECONOMIST: Neutrinos

If all particles in the universe were massless, then, the universe would look to them to be infinitely small.

ECONOMIST: Cosmology

Without it, or something like it, some of the Standard Model's particles that actually do have mass (particularly the W and Z bosons) would be predicted to be massless.

ECONOMIST: The Higgs boson: Fantasy turned reality | The

The consensus among physicists is that particles began massless and got their mass subsequently from something known as the Higgs field the search for which was one reason for building the Large Hadron Collider, a huge and powerful particle accelerator located near Geneva.

ECONOMIST: Cosmology