On Thu, Jul 31, 2014 meekerdb <[email protected]> wrote: > >> Our quantum theories may need work. Quantum theories of Physics insist > that space is quantized just like everything else, > > I don't think that's true. In fact all quantum field theories assume a > continous spacetime. >
That is true but the phenomenon that quantum field theories are so good at predicting exist at a scale that seems inconceivably small to us but is astronomically larger than the Planck length. The Planck length is to a uranium nucleus as a basketball is to the Milky Way; none of our theories even pretend to make predictions when things get anywhere near that small. The idea behind the Planck length is that as the wavelength of light gets smaller its energy gets larger, but according to Einstein energy is just another form of mass ( E = MC^2) so at some point it is so small and so energetic (massive) that it becomes a black hole. The Planck time is the time it takes light to travel the Planck time, and right now it doesn't make sense to talk about smaller things; that might or might not change when somebody finds a better theory of gravity than General Relativity. If you assume continuous spacetime you can get excellent approximations unless things get really REALLY small, and then our theories break down. Because nobody can explain what is happening when things get smaller than the Planck Length or time gets shorted than the Planck Time, some have assumed that's because nothing is happening at those scales because space and time are quantized; but there is zero experimental evidence to think that is true and some evidence to think it may not be. Nobody really knows. > It is the smallest size that could in principle be measured *assuming a > classical theory of gravity*. To measure something smaller would take a > photon of such short wavelength it would form a black hole - but all this > is assuming that the formation of such small black holes still obeys the > classical equations of GR. > At the center of a Black Hole Spacetime is INFINITELY curved, and General Relativity breaks down at that point; it can deal with astronomically large curvature but not infinite curvature. > The paper I cited, arXiv:1109.5191v2 [astro-ph.CO] 18 Apr 2012, says > [...] Which corresponds to the granularity being smaller than the Planck > length by a factor of 1/525. > If that finding holds up then our existing quantum theories most certainly need work because all of them say things that small can't exist. John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
