Whenever I give a planetarium show to an audience, I always like to let time pass quickly.  The stars appear to move, but I quickly point out that it is in fact the planet Earth turning that gives the stars their apparent motion through the night sky.  I then reassure them that stars do move, it just takes a very long time for them to move a noticeable amount.  Why is this? The above animation of Barnard’s Star is a clue.  Photographed once per year, Rick Johnson created this animation showing the movement of the small red dwarf.  Barnard’s star...