There will be a lunar eclipse visible throughout most of the United States on the morning of November 19, 2021. To download your free viewer’s guide for the November 19th lunar eclipse, click here.
What is a Lunar Eclipse?
A lunar eclipse occurs when the shadow of the Earth blocks sunlight from reaching the Moon. A lunar eclipse can only occur during a Full Moon.
The shadow cast upon the Moon during a lunar eclipse is large because the Earth is large compared to the Moon. The umbra is the part of the Moon that is in the deepest shadow because it is completely blocked from the Sun. The penumbra is the part of the Moon that is partially blocked from the Sun.
Lunar eclipses aren’t quite as dramatic as solar eclipses, but they do last for a longer time because the umbra is so much bigger in a lunar eclipse. In a lunar eclipse, the light that reaches the Moon has been filtered through the Earth’s atmosphere which makes the Moon change color. During a lunar eclipse, the color of the Moon can range from a very dark brownish red to a bright copper color. Several factors impact how the moon will look including the amount of ash, smoke and dust in the Earth’s atmosphere.
It’s interesting to watch the shadow, as it’s one of the ways that ancient astronomers were able to realize that the Earth is round.