If the moon is in the shadow of the earth during a lunar eclipse, how can we still see it? And why does it turn red? The answer has to do with our own sunrises and sunsets. This is followed by a transcript of the video.
Narrator: A lunar eclipse in the Bloodmoon was not always something to look forward to. When the moon went red thousands of years ago, the ancient Mayas and Mesopotamians feared that something monstrous and evil had eaten the moon. They would scream in the night sky to fend off the starving beasts. And since the average lunar eclipse lasts about 100 minutes, when the moon then returns to normal, they were probably convinced that their wheezing and howling actually worked. We now know that the moon does not need our protection. But why is it getting red? Whenever you look up to a full moon, you see sunlight reflected off the lunar surface. So if something blocked the sunlight, say the earth, then theoretically the moon should disappear out of sight. But during a total lunar eclipse, when the moon passes through the Earth's shadow, we get a red moon, not a vanishing one. So what's up? To find out, we make a short trip to the lunar surface. This is a NASA simulation of what the Earth looks like during a total lunar eclipse. Notice the red ring around our planet. Everywhere you can see that the ring is either a sunrise or a sunset. And while it is true that at this moment no direct sunlight reaches the lunar surface, the Earth's atmosphere bends the red wavelengths of light around the planet. This redness, seen during a lunar eclipse, is a combination of light from every sunrise and sunset on Earth, all happening simultaneously. So the moon appears red, for the same reason that sunrises and sunsets on Earth are red because of a phenomenon called Rayleigh Scattering, named after British physicist John William Strutt, also known as Lord Rayleigh, who discovered it at the end of the 1