Bob Moler's Ephemeris Blog

Thursday, July 7th.  Today the sun will be up for 15 hours and 24 minutes, setting at 9:29.   The moon, 1 day before first quarter, will set at 12:43 tomorrow morning.  Tomorrow the sun will rise at 6:05.

The moon changes its phase daily as it orbits the earth.  Some still think that it has to do with the earth’s shadow.  Now that does happen for a few hours during a lunar eclipse at some full moons.  However the moon’s phase is simply the moon in sunlight, the same sunlight that falls on the earth.  The dark part of the moon is simply the night side of the moon.  It changes because the moon orbits the earth and the farther it appears from the sun, the fuller it appears.  This can be proven with a small ball.  When the moon’s out in the day time, like it is now before sunset, go out in the sunshine and hold or toss the ball up in the direction of the moon.  The ball will have the same phase as the moon.

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