On 26 December 2013 07:23, Jesse Mazer <[email protected]> wrote: > The notion that everything "travels through spacetime at the speed of > light" was popularized by Brian Greene, but it only works if you choose a > rather odd definition of "speed through spacetime", one which I haven't > seen any other physicists make use of. >
Mainly because it doesn't make sense. Speed is change of position with time, hence "speed in spacetime" equates to the angle a world-line makes relative to some world-line chosen as a basis, e.g. the rest frame of the Hubble flow. Things don't move through space-time, they move through space. They are 4 dimensional objects embedded in space-time. -- 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/groups/opt_out.
