I feel bad for ancient peoples. You know, there's all like the diseases and lack of refrigerators. And frozen yogurt that, you know, makes me feel bad for them, but especially I feel bad of how they were incapable of predicting solar eclipses. You see, solar eclipses because of the angle of the moon and the orbit around the earth and the small size where everything has to line up just right, it's almost impossible to predict solar eclipses. Like there are kind of regular patterns, but you know, in a solar eclipse comes every two-ish years somewhere on the earth, but any one particular location is only going to get a solar eclipse every couple hundred years. And then every country, like extended region, is only going to get one every few decades. And ancient astronomers, you know, would pay attention, they would record eclipses, they would have histories of this. And they would notice kind of patterns like, oh, if we have one, then like, oh, there will be another one in 18 months, unless it's, you know, unless it's like the third of the cycle. And then we have to add like a half a year and some trial is like, it was just super complicated. And they could never really accurately predict them. Like they might be able to say, you know, maybe this month there might be an eclipse kind of sort of, I'm guessing, isn't the best way to be an astronomer. This all changed in 1715. And this all changed with the greatest assist in scientific history. You see earlier, earlier, Isaac Newton had developed all of his laws of motion, you know, the, you know, motions or objects in, in motion, tend to stay in motion, objects to rest, tend to stay at rest, force equals mass times acceleration, opposite equal reaction, all that, all the good old fashioned Newton's laws. And Newton had a realization. And he had this realization when, according to him, he saw an apple falling from a tree. Like there's this classic picture and we assume it's like this Smith, but it's according to him that he had a snap when the apple fell from the tree. Because as he watched the apple fall, he realized that the apple is accelerating. Yeah, because it's moving. It was not moving now. It's moving that requires an acceleration force equals mass times acceleration. If the apple is accelerating, then there must be a force on the apple. Like nothing's pushing it. There's no strings, but there is a force to cause that acceleration. Let's call this the gravitational force. And here's Newton's big insight. Forces have an equal and opposite reaction. If there is a force pulling on an apple coming from the earth, then there must be a force from the apple pulling on the earth. Forces must be in balance. So whatever is pulling on the apple, let's call this gravity, the earth is pulling on the apple. The apple must be pulling on the earth with the exact same force of gravity. And if it's happening here between an apple and the earth, it's happening everywhere throughout the universe. The gravity is universal. Using this insight of his laws, emotions applied to this thing called gravity, he was able to calculate the speed of the orbit of the moon. It's like, oh, if it's an orbit, this is math. You figured it out. But you didn't publish it. He wrote it all up and he's like, oh, this is pretty interesting. And he put it on a shelf and he went all their stuff. But his best buddy, Edmund Haley, got talking to Newton, they're having chat, having some pints or whatever. I'm sure it just came up in conversation like, oh, yeah, I figured out gravity, whatever. And he was like, what? Tell me more. And I'm sure this is all fictionalized, of course. Newton's like, well, I've applied laws of motion. There's this universal gravity, figured out the orbit of the moon, applied it to other, but that's just kind of boring. It was just, you know, there's a waiting kill in afternoon, I guess. And Haley's like, did you realize how big of a deal this is? Please publish, he's like, nah, nah, and Haley's like, dude, publish this. This is a big deal and an Isaac Newton's like fine. If you say so, I'll do it for a friend, I'll do it for you. So he publishes it, blows up the world. Haley's like, I told you so, dude. And Haley, Edmund Haley, was like the first person to apply Newton's work on universal gravity to like everything. He's like, I don't understand that. I'm going to try universal gravity. I don't understand that. I'm going to try universal gravity. The whole Haley's common thing, universal gravity. And he also worked on the eclipses. He had access to ancient records of eclipses. And now that he could predict the motion of the moon, and he could predict the motion of the earth around the sun to very, very accuracy, not using any cycles or rhythms or trying to guess at it, but just crunching through the math of using gravity, he was able to predict. Haley was able to predict any eclipse. The eclipse occurred in May of 1715, over London, which is where he lived. How convenient is that? He was able to predict the occurrence of the eclipse to within four minutes, four minutes. And that's the only reason he was off is some tables of the periods of the moon that he's using to calculate the orbit was a little bit off. That's it. Four minutes. For the first time in human history, someone had accurately predicted an eclipse. And it was because of Newton's laws, but it was an Haley applying it for minutes. How ridiculous is that? Now no computer, no calculator, just good old pen and paper, quill and paper. Sure. Hand calculations able to predict. And he made a map too. He made a map of the path of the eclipse. And if you've ever seen an eclipse map, this shows like the shadow and then like 90% coverage, 65% coverage, etc. and like lines going across. Yeah, Haley like did that. You can go look at a map from 70 of Haley's eclipse from 1750. It looks like a modern day map of an eclipse. How does was he able to figure out like the shape of the shadow and where it occurred and how long it will last using universal gravitation? Thank you, Newton, but most especially, thank you, Haley. Thank you so much for watching. I hope you liked it. Don't forget to like, share and subscribe and go to patreon.com slash pmsutter so that we can have some universal gravitational support. Sure.