In 1976 Bill Unruh at British Columbia realized that acceleration has an intrinsic temperature---an accelerating observer will be bathed in radiation at that temperature. He published his finding in Physics Reviews Series D vol 14 page 870 and following. the Unruh temperature has been experimentally investigated at SLAC, and possibly elsewhere here is a SLAC press release about the work of P. Chen on Unruh radiation http://www.slac.stanford.edu/slac/media-info/20000605/chen.html The formula for the temperature associated with acceleration a is kT = hbar a/2πc Here is an example in planck units c=G=hbar=k=1 Suppose the acceleration is 18E-30 then to get the temperature we need to divide by 2π That gives about 3E-30---a bit hotter than the familiar boiling point of water. So if one accelerates a teakettle of water at 18 x 10^-30 planck, it will soon boil and one can brew tea with it. All that is necessary to find the temp is to divide by 2pi. this partily in response to dav2008, who in another thread mentioned the planck unit of acceleration Unruh's formula is similar to Stephen Hawkings formula for black hole temperature which depends in the same way on the surface gravity (acceleration at the event horizon).