welcome all I'd like to know if there is a way to calculate how manny photons are in this universe. We can calculate the mass of the universe so is there a way to claculate the number of photons? I also would like to clear some things i dont understand. I read that if people build a ship that will be able to reach the speed of light then the moment it reaches the speed of light it will have infinite mass, energy, gravity, force and magnetism. Does a photon have all these? All answers are welcome. Thank you!