Question

Can light be converted into mass?

Answer 1

Yes - by photon-photon collisions. The idea that massless particles of light - photons - can be converted into 'matter' particles was first proposed by American physicists Gregory Breit and John Wheeler way back in 1934. They theorized that it would be possible to create matter by smashing together two photons. The process could lead to formation of an electron and positron.