Can particles have negative mass? If so, what would it mean?
Can we possibly have particles with negative mass?
Can a massless particle have no momentum? What is the difference between a weightless particle and a particle which has mass? How can massless particles (photons) have momentum? Can velocity of a particle be negative? If a particle has no mass, how can it still be defined as a particle and not just a waveform? Does dark matter have negative mass? Do massless particles have to travel at the speed of light? How could a particle with a known mass go through a solid wall? Why don't photons have mass? What does it mean for a particle like a photon to have a rest-mass of zero? Physics: Why don’t photons have mass? Do photons, the particles of light, have mass? Why are there so many subatomic particles? Can we create virtual particles? Are subatomic particles visible? Can a pair of positive and negative energy virtual particles pop into existence from the vacuum? Does 'empty' space have mass which is displaced by the particles of matter which exist in it and move through it? Can we create some mass from energy? Does potential energy have mass? How can a photon have no mass when E=mc^2? Do elementary particles have shape? Why does light have no mass? How can a photon not have mass but still have momentum? Does energy have mass? In an atomic structure, there are subatomic particles of protons, neutrons and electrons. In these three, which two of them have a similar mass? Does an object moving in a vacuum lose mass? Is quantization of mass possible? Can we turn mass to energy and vice versa or is it theoretical only? How could potential energy be negative? What are sub-atomic particles?