Bob Moler's Ephemeris Blog

Ephemeris for Friday, February 22nd.  The sun will rise at 7:31.  It’ll be up for 10 hours and 49 minutes, setting at 6:21.   The moon, 3 days before full, will set at 5:55 tomorrow morning.

Yesterday I talked about the invariability of the speed of light in a vacuum.  This would seem to put interstellar travel on the list of things that can’t be done.  Apparently General Relativity has ways of getting around.  I’ll leave that to smarter people to explain.  But one cool thing about the speed of light is that it allows us to see into the distant past.  The farther the object is away the farther back in time we can see it.  With the Hubble Space Telescope in its Deep Field images of galaxies can see back to within perhaps a billion years of the Big Bang, at least for a few galaxies.  The James Webb space telescope to be launched later this decade will explore, among other things more deeply into this unknown time to see how these galaxies formed.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.