Sciency Words: Baily’s Beads

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

BAILY’S BEADS

This is going to be a quick one. I sort of blew all my writing hours this week finishing the first episode of my new short story series: Omni-Science. I don’t regret that. Writing Omni-Science felt awesome, and I hope you liked reading it.

The writing prompt that inspired Omni-Science was this photograph of the “Mondretti cylinder.”

That’s a very strange and mysterious image, certainly strange and mysterious enough to get the machinery in this writer’s brain started. But being the science nerd that I am, I also recognized that this is actually a time-lapse/composite image of a solar eclipse, showing off the “Baily’s beads” effect. (Also when I downloaded the image, the file name had the words “Baily’s beads” in it, which removed any doubts I had about what I was really looking at.)

As I’m sure you know, the Moon is not a smooth, perfect sphere. It’s covered in craggy terrain, and so during an eclipse, just before the Sun disappears entirely behind the Moon, the last rays of sunlight peak out from the gaps between mountains and craters and so forth. As a result, those of us who are using proper safety gear get to see these “beads” of light around the edges of the Moon.

I’m guessing Francis Baily was not the first person to notice this, but in 1836 he became the first to explain it in a paper for the Royal Astronomical Society titled “On the remarkable phenomenon that occurs in total and annular eclipses of the sun.” Those 19th Century English astronomers certainly did have a way with words, didn’t they?

10 thoughts on “Sciency Words: Baily’s Beads

    1. As I understand my Star Trek physics, this is why the Enterprise has a navigational deflector array. Without that, at warp speed you’d smash into every single stray speck of matter or radiation between here and the neutral zone, and rip your starship to shreds.

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  1. I have to admit that I picked the image just ‘cos I liked it, and ‘cos I felt it would do that very thing you described – getting the brain working, providing a spark of creativity. But finding out a) what it is and b) what that actually means is an unexpected bonus. Thank you James 🙂

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