I understand that it’s impossible to bring a photon to a state of rest, therefore impossible to collect them into a cup to weigh them and calculate their mass. A guy in a pub explained to me, quite smugly, that photons are just expressions of energy and that’s that. From my understanding solar sails would be just large surface areas being hit by photons, pushing the spacecraft in a desired direction, just like normal ship sails are being pushed by wind. But air particles do have mass. How could photons push the spacecraft if they don’t weigh anything?
In: Physics
Ok, I’m probably going to butcher this, but it was answered a while ago on this sub and I’ll give it a shot from what I recall of that. Photons do not have mass, but as your drunkard friend explained, they *do* have energy in the form of momentum. That energy/momentum is imparted onto the solar sail when they bounce off of it to give it momentum. Also, there’s some math involving E=MC^(2) That someone will fill in below.
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