00:00A lunar eclipse happens when the Earth blocks some or all of the Sun's direct
00:08light from reaching the Moon. This cosmic event only takes place during a full
00:14Moon, which happens once every 29 and a half days, or the length of one full
00:21orbit of the Moon around the Earth. So why don't we have an eclipse every month?
00:28The Moon's orbit is tilted a few degrees in relation to the Earth, so the Earth,
00:34Moon, and Sun don't always align. When the Earth does eclipse the Sun, it casts two
00:41types of shadows on the Moon. A larger shadow, known as the penumbra, and a
00:48smaller, darker shadow, known as the umbra. There are three types of lunar
00:55eclipses. The first is a total lunar eclipse when the Sun, Moon, and Earth are
01:01in perfect alignment and the Moon falls within the Earth's umbral shadow. Total
01:08lunar eclipses are the most striking of the three types because they turn the
01:12Moon a sunset red. While shorter blue wavelengths of light are scattered outward
01:18by the Earth's atmosphere, longer red wavelengths are refracted, or bent, inward
01:24toward the Moon, making it appear red. The brightness of the Moon's red glow
01:29depends upon how much dust and clouds are in the Earth's atmosphere. Following
01:34volcanic activity, ash can block out enough light to render the Moon a darker
01:38red, or even near black. A partial lunar eclipse, the second type, occurs when the
01:45Earth, Moon, and Sun don't perfectly align, so only part of the Moon passes into
01:50Earth's umbra. Earth's shadow appears very dark on the side of the Moon facing
01:56Earth. Last, a penumbral lunar eclipse occurs when the Moon passes through Earth's
02:03penumbral shadow. The event is so subtle that most people don't even notice. The Moon
02:10will appear just slightly darker than normal. Lunar eclipses occur up to three
02:17times a year and can be observed from the entire nighttime half of the Earth. Unlike
02:23during a solar eclipse, it's safe to look at the Moon with the naked eye during a
02:28lunar eclipse. It is only because of the distances of the Sun and Moon from the
02:33Earth that we are able to witness total lunar eclipses. As the Moon enters a
02:40space away from the Earth each year, one day, billions of years from now, the Moon will
02:46be too far away to fall completely within Earth's umbral shadow. Until then, we can
02:51occasionally enjoy seeing our own planet's shadow cast upon the largest object in the
02:56night sky.
03:10happinessheer.
03:12sulla
03:13quantity
03:13accomplishments
03:13celia to the Moon
03:14Bodent
03:16commence
03:17back to
03:19the 1700s
03:19Tribe social
03:21ed
