The Theory of Relativity proposes equivalence between mass and energy. Well... since they are "equal", when mass disturbes the spacetime which causes a forcefield that we call gravity, energy should have the same effect on spacetime. Putting a huge amount of mass in a very little place in space, we have a black hole. After this little explanation my question ;): Does any Kind of energy have the same effect? Thus heating up some gas to a 10^xxxxxxxxxxxx Temperatur would -in the end, theoretically- cause a black hole beeing created? Another example would be a gigantic magnetic field. Which causes such a large density of energy in a certain place that spacetime would collapse? Now my last and maybe most controverse example: Is it possible to accelerate an object on such a high speed that his kinetic energy (from the frame of reference of the observer) would cause the object to let spacetime around it collapse into a black hole? I thought maybe this effect would not appear since time slows time in the frame ofthe accelerated object. Thus making its spacetime more "spread out". And working against the black-hole thing. And last but not least: if you place the observer in the object which is Now flying veryvery close to the speed of light. wouldn't everything else which hasn't been accelerated look like a black hole? I'm just wondering and would love to get some answers of people who really know this stuff.