Courtesy of EarthSky
A Clear Voice for Science
The cool thing about the last quarter moon is that it shows you in which direction our planet Earth is revolving around the sun. At quarter moon, the lunar disk is half-illuminated in sunshine and half-engulfed in the moon’s own shadow. The terminator – the shadow line dividing the lunar day from the lunar night – shows you where it’s sunset on the waning moon.
The moon reaches its last quarter phase tomorrow – on Saturday, October 30 – at precisely 6:46 a.m. Mountain Daylight Time (12:46 Universal Time). For the Central Time Zone in North America, the last quarter moon falls at about the same time as sunrise. On the Pacific Coast, the quarter moon takes place before dawn. On the Atlantic Coast, quarter moon occurs in the early morning after sunrise – but you should still be able to see it in your southwest sky.
Although the clock readings differ by time zone, the last quarter moon happens at the same instant worldwide. Our chart shows the moon high in the southern sky at dawn tomorrow, when the moon will be reasonably close to last quarter for all time zones in the continental United States.
The Earth speeds along in the general direction of the last quarter moon at some 67,000 miles per hour!
Written by Bruce McClure