Overnight on March 24th and into the 25th, the Moon will pass through the outer part of Earth’s shadow, creating a faint lunar eclipse called a penumbral eclipse. Now, the more spectacular variety of lunar eclipses happens when the Moon passes through Earth’s inner shadow, or umbra. That’s when we see a dark “bite” taken out of the Moon, or in the case of a total lunar eclipse, a reddish, so-called “blood moon.” Penumbral eclipses cause only a slight dimming of the Moon’s brightness, so if you’re not looking for it, you might not know there was an eclipse happening. But if you glance at the Moon early in the night, and then later, around the peak of the eclipse, you might notice the difference in brightness.