1. Does light(photons) have 0 mass or infinite?(b/c it its mass would be zero, it would take no energy to slow it down, meaning, it wouldn't be traveling, unless it has infinite mass which means that it can't be slowed down even a bit but that contradicts the theory that it does have 0 mass) 2. If you turn your torch on in a complete locked up dark place, and then turn it off, why isn't it always bright? I mean since light doesn't go through walls and it doesn't accelerate, shouldn't it be enough to give you brightness forever? 3. I heard somewhere that photons travel twice the speed of light b/c all the other matter recieve info such as they are suppose to attract to each other or repel at the speed of light so photons have to travel twice the speed of light for them to know that they are traveling at teh speed of light. Well, doesn't it mean that they have negative mass?