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Lunar Eclipse – Science at Night



There are few subjects our boys enjoy more than science. So when we heard about the series of blood moons coming in the next couple of years, we knew we had to watch at least one of them!

For those of you who haven’t seen the news in the last several weeks, a blood moon is a complete lunar eclipse, and the moon in eclipse takes on a reddish hue.

According to WikiPedia:

“The shadow of the Earth can be divided into two distinctive parts: the umbra and penumbra. Within the umbra, there is no direct solar radiation. However, as a result of the Sun’s large angular size, solar illumination is only partially blocked in the outer portion of the Earth’s shadow, which is given the name penumbra.

“A penumbral eclipse occurs when the Moon passes through the Earth’s penumbra. The penumbra causes a subtle darkening of the Moon’s surface. A special type of penumbral eclipse is a total penumbral eclipse, during which the Moon lies exclusively within the Earth’s penumbra. Total penumbral eclipses are rare, and when these occur, that portion of the Moon which is closest to the umbra can appear somewhat darker than the rest of the Moon.

“A partial lunar eclipse occurs when only a portion of the Moon enters the umbra. When the Moon travels completely into the Earth’s umbra, one observes a total lunar eclipse. The Moon’s speed through the shadow is about one kilometer per second (2,300 mph), and totality may last up to nearly 107 minutes. Nevertheless, the total time between the Moon’s first and last contact with the shadow is much longer, and could last up to 4 hours.[1] The relative distance of the Moon from the Earth at the time of an eclipse can affect the eclipse’s duration. In particular, when the Moon is near its apogee, the farthest point from the Earth in its orbit, its orbital speed is the slowest. The diameter of the umbra does not decrease appreciably within the changes in the orbital distance of the moon. Thus, a totally eclipsed Moon occurring near apogee will lengthen the duration of totality.”

Frankly, I did not expect this to be very dramatic. Yet there we were, all four of us, sitting in amazement at the sheer beauty of the event. The moon when from looking like a flat disc as usual, to looking like a glass marble that someone had put a flashlight up against. We just couldn’t stop talking about how beautiful it was.

On the west coast, we started seeing the moon disappear a little after 11pm. By just past midnight it was completely eclipsed and this gorgeous reddish-orange-ish marble was glowing in its place. We sat and started at this phenomenon and talked about eclipses of all kinds, how they happen and suddenly truly came to understand how a complete lunar eclipse could frighten the ancients.

There are a variety of beliefs surrounding lunar eclipses, among them:

  • Chinese tradition says there is a Three-legged Toad who lives in the moon, which swallows it during an eclipse.
  • Southern Slavs and Buriats would pray and yell, shoot and throw stones in order to chase away an encroaching demon.
  • In some parts of the world, a naga or dragon was held responsible for the event, which was often believed to be a bad omen.
  • Egyptian mythology holds that a lunar eclipse is due to Set’s crime of stealing the Moon Eye of Horus. Thoth searched in the darkness and restored to its rightful place in the sky.

Eclipses are a fantastic time to discuss mythology, science and even create an art project from it. Once our replacement ink comes in, we will be printing my lunar sequence image, and putting together a report based on it. You’re welcome to use this image in your own schoolwork, click on it to open up the full size image.

What do you think?