Looking west from our Littleton farm this morning, I saw a darkened, reddish moon with a bright, bluish rim along its top edge; the time was 5:50 AM, about an hour before dawn. In fact, I was witnessing a total lunar eclipse, as Earth's shadow temporarily blocked sunlight from illuminating the moon.
This morning's total lunar eclipse, best observed in the western U.S., will be the briefest this Century, lasting about 5 minutes. While partial lunar eclipses are relatively common, total lunar eclipses are rare; for any given location on our planet, only 4-5 can be observed each decade. The term "blood moon," describing the reddish appearance of the lunar surface, results from the scattering of sunlight by Earth's atmosphere; during a total lunar eclipse, only the longer wave lengths of the light spectrum (i.e. red light) reach and are reflected by the moon's surface.
Observing such astronomical spectacles, now explained by our knowledge of planetary motion and light refraction, one can easily understand how early man viewed them as omens, igniting a propensity for mysticism that still haunts our species.
