Bob Moler's Ephemeris Blog

Ephemeris for Monday, February 6th.  The sun will rise at 7:55.  It’ll be up for 10 hours and 1 minute, setting at 5:57.   The moon, 1 day before full, will set at 7:21 tomorrow morning.

What time is it?  Don’t bother to check.  This time It’s a rhetorical question.  The basis of time keeping has always been astronomical.  Astronomers almost lost it last month.  There are now two time scales.  Universal Time, that’s roughly in sync with the earth’s rotation and Atomic Time, which uses the vibrations of cesium atoms which are set to count seconds of the length they were in 1900.  Thanks mostly to the moon and the drag of the tides the earth is slowing its rotation.  The difference between the two time scales is over a minute, accumulated over that past 112 years.  Universal Time has been tied to  the earth’s rotation by the occasional addition of a leap second every year or two.  The next leap second will be added on June 30th.

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