My question is two-fold: 1). I understand that according to Einstein's theories that as one approaches the speed of light, e.g. interstellar flight in a spaceship, the mass of the moving object approaches infinity. E=mc^2 the increasing mass correspond to an increasing amount of energy. Is this energy in the form of potential energy, i.e. could be released by a collision with another object, or some other type of energy? 2). In reference to my first question, is there any relationship between the energy of a moving object and thermal energy? I know that c is the upper limit for speed of an object, but does mean it has the maximum amount of energy it can store as potential energy? Is there an upper bound for thermal energy? I have heard that thermal energy is the kinetic energy of particles in a system. I also have heard that all bodies emit thermal radiation in the form of black-body radiation, but I've never heard of any object emitting energy because of the speed its traveling at. Is there any correlation between the thermal energy of a hot object, e.g. a hot cloud of plasma, and the energy of a moving object,e.g. a fast moving comet? I have no real knowledge of physics so feel free to correct me if I have missed anything or made absurd assumptions.