Bob Moler's Ephemeris Blog

Ephemeris for Thursday, February 21st.  The sun will rise at 7:32.  It’ll be up for 10 hours and 46 minutes, setting at 6:19.   The moon, half way from first quarter to full, will set at 5:21 tomorrow morning.

The speed of light at 186,000 miles a second or 300,000 kilometers a second.  It is the ultimate speed limit in the universe.  nothing with mass can match is speed.  But particles without mass, like photons, travel at that speed in a vacuum naturally.  That speed of light in a vacuum was a constant was postulated by Albert Einstein and was the central part of his Special Theory of Relativity published in 1905.  In physics the lower case letter c represents the speed of light in a vacuum.  And its figures in Einsteins most famous equation, which actually wasn’t part of special relativity: e=mc².  The equation that changed the world for good or ill.  Science itself is nether good nor bad.  It’s how that knowledge is applied.

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