Why don't photons have mass?
Physics: Why don’t photons have mass?
What is the mass of photon? Is light really a type of energy? If light does not have mass, then how can it bend due to gravity? How can light have momentum if mass is 0? Do massless particles have to travel at the speed of light? If photons have no mass, how are solar sails pushed? Does energy have mass? Why does mass become infinite at the speed of light? What is the shape and volume of a photon? What is the difference between a weightless particle and a particle which has mass? Can a massless particle have no momentum? What is the size or volume of a photon? What is the size of a photon? How big is a photon compared to an atom? How big is a photon? If a particle has no mass, how can it still be defined as a particle and not just a waveform? Can particles have negative mass? If so, what would it mean? Is light made up only of photons? What happens to the mass of an object if it travels with the speed of light? Does Light attract Light? Light is energy therefore E=mc^2. If it has mass it has gravity? What is actually mass? Is energy a form of mass? Photons are 'bend' downwards by mass; what does this say about the relation between photons and gravity (tons) and which particles would bend upwards? How did they calculate the size of a photon? What happens to a mass of an object when it moves with the speed of light? The photon moves at the speed of light. In that case the mass of the moving photon is infinite according to Einstein's theory of relativity. Does that mean that photons warp space time infinitely? What fundamentally gives matter mass? How does a photon lose energy? How can light provide momentum to solar sails if its mass is zero? What is the mass of an electron? What gives matter its mass? Does 'empty' space have mass which is displaced by the particles of matter which exist in it and move through it?