I've read a few articles on the highest possible temperature with different results, usually something like 10 to the 32nd power kelvins. Can someone explain to me why the two other possibilities below are not plausible? 1. Hottest possible temperature being all matter in universe converted to energy + all other energy in universe converted to heat energy. I doubt my terminology is correct, but hopefully you get the idea. 2. Because temperature is a measure of movement of molecules, and the speed of light is the fastest possible speed, would the movement (vibration) of molecules at or near light speed render the highest possible temperature? Thanks. -Black
http://en.wikipedia.org/wiki/Hagedorn_temperature http://en.wikipedia.org/wiki/Planck_temperature Neither are limits of temperature, they are the limits of temperature within a particular theory or framework. At 10^32 K you find you've enough energy to start producing a lot of Planck mass objects, which results in you needing a quantum theory of gravity to describe it properly. In string theory you get large strings being produced in huge numbers. Basically your approximations about the nature of space and time break down because there's so much energy about you can not longer treat space-time in the way general relativity does, but instead you need to view it as a quantum theory.
Hi black, I'll give it a shot. The problem here is that temperature doesn't just depend on available energy, but also on how concentrated that energy is (speaking pretty loosely). For example, if you added 100kJ of heat into a bucket of water, you'd raise its temperature by about 2.5°C. But if you added 100kJ of heat to a US penny, you would vaporize it into a cloud of very hot zinc gas, or (under enough pressure) perhaps a puddle of liquid zinc at maybe 100,000°C! A second problem is the difficulty in determining how much mass-energy is in the Universe, and also in considering just how much of that energy the 2nd law of thermodynamics would allow you to cram into the target area. Temperature is a measure of the kinetic energy of molecules, not their speed. As the speed of a molecule approaches light speed, its kinetic energy grows without limit, and so does the corresponding temperature. Standard disclaimer applies: Don't take my word for it - I'm just some random guy on the Internet. Please Register or Log in to view the hidden image!
