The Shadow Knows! A Lunar Eclipse.
Blog vol 5.14. The Shadow Knows! A Lunar Eclipse.
From 1930 to 1954 there was a very popular radio drama called “The Shadow” in which Lamont Cranston, a detective with superpowers, solved crimes and apprehended nefarious criminals. The program began with the question, “Who knows what evil lurks in the hearts of men?” The shadow.
Last night most of the world saw another shadow over a Harvest Super moon, a remarkable event in the celestial calendar. Talk about drama, Marvel Studios could have made an epic movie, The Shadow on the Moon, or Shadowed Harvest. Actually in real life, it was disappointingly undramatic. I think the main reason was the crazy drama of a total solar eclipse in early April, 2024, made this lunar eclipse pale by comparison. There I was last night (September 17), having heard the word “eclipse”, expecting to be wowed by the dance of sun, moon and earth.
The word “partial” was included with “eclipse”, which makes a big difference. In April we had a “total” solar eclipse, in which the moon is perfectly placed to completely shadow the sun during midday. Last night, the lunar eclipse happened when the earth created a shadow that part of the moon passed through.
In a total lunar eclipse, the central shadow of the earth, the umbra (Latin for shadow) covers the entire moon resulting in a darkened moon which turns to red. The light that is reflecting off the moon has come through the earth’s atmosphere, much like a red sunset but a lot dimmer, creating a “blood moon”. Really cool.
In a partial lunar eclipse, part of the moon passes through the umbra, which we saw on the top half of the moon last night, and the rest is in the penumbra (Latin for almost shadow). Still quite dramatic. Over time the moon dances around the umbra emphasizing the moon’s movement through space. One neat shot from Wikipedia with multiple images overlaid with time lapse captures it nicely.
What I could not really see last night was a change in the light that was coming through the penumbra on the rest of the moon’s surface. It was really difficult to pick up any dimming, let alone a colour change. I did see a coloured ring in the clouds around the moon that did have some red tones, but difficult to say. The dimming is only by 10% when it goes through the penumbra, so you would need a light meter to fully appreciate it, I’m not sure it can be detected by the eye.
The really cool thing is that all these celestial bodies are out there moving about all the time and in very predictable regular patterns, so we know what to look for and when. The next total lunar in some parts of the world, including the Americas, is March 13/14 2025. Mark your calendars. (I think I will bring a light meter this time).
The good doctor
