I saw Jupiter the other day

 The other day I was walking home from a walk when I saw Jupiter. I didn't know that it was Jupiter when I saw it. You'll agree that it's difficult to tell the planets apart when they're so far away. But I saw that it was this big bright glowing thing in the sky, and it wasn't twinkling, so it couldn't have been a star. So I went to get my phone where I have this app installed that shows you where the planets are using your phone's gyroscope. And I learned that it was Jupiter. I took a picture of it, and some pictures with it. It's not every day that you get to take a selfie with Jupiter. It's like running into a celebrity. You hear about it basically your whole life. I can't even remember the first time I learned about Jupiter, I was probably 3 or something. And then one day, you're just walking on the street, and it's there in front of you. I was starstruck. Or rather, planetstruck!

Jupiter in the distance, taken by me

So then I decided to look up some information about Jupiter. It's the big orangish one with the big red spot on it. Its iconic red spot. That spot was observed as early back as the 17th century! And it was probably not even the same spot as we see right now. The spot isn't like, a permanent physical fixture. It's a storm. An anticyclone, which means the center is the high-pressure spot. So it seems likely that back in the 1600s they were looking at one storm, and then that dissipated, and now we're seeing a different storm that is also a big red spot.

"Jupiter" by Donato Creti (1711) depicting the red spot

The first person who described the spot was Robert Hooke. I hadn't known about this discovery of his, but I did recognize his name, due to Hooke's Law! It's a law of physics about forces and springs. People like him are called polymaths, who study all sorts of different things. It's always so bizarre to find out a guy who discovered one famous scientific concept also discovered a completely different scientific concept in a completely different area. Newton is the same way. He did so much work regarding forces and laws of motion and energy. He is the namesake for a unit of force. He also disovered the refraction of light. The whole "white light hits lens, gets divided into a rainbow" thing, ROYGBIV, that was Newton. The Pink Floyd album cover.

The Dark Side of the Moon

Galilei is another one of these guys. AND he discovered Jupiter's moons! Its four moons, that we now call the Galileian moons. I sometimes forget just how long ago the invention of the telescope was. He found the moons back in 1610. BUT there was another guy. Simon Marius. He also observed the moons, but didn't publish his findings until a while later. When he did publish the findings in a book, he claimed that he discovered the moons a month before Galileo. Galileo was pissed. He accused Marius of plagiarism and kinda ruined his life and reputation. One of Marius' previous disciples was like, a mass plagiarist of Galileo, so there was already some bad blood there.

Historians now have looked at the evidence and found out that Marius actually did find the moons independently of Galileo, on his own. But it wasn't a month earlier, it was literally A DAY later. Incredible conicidence, and it probably means that the moons were in a particularly observable spot around those days. It's just that the two of them were using different calendars. Marius was using the Julian calendar, where he discovered the moons in December. Galileo was using the Gregorian calendar, where he discovered the moons in January. Marius' life was ruined, but he gave names to the four moons, and we still use those names. So in a way, people still know about his work and honor his decisions regarding the discovery. So he still has some sort of good legacy. Which is kinda bittersweet. Mostly bitter.

The first time EVER that the speed of light was estimated was thanks to Jupiter and its moons. They were able to calculate the trajectory of the moons and knew what locations they should be at at any given point. Cassini noticed that when Jupiter was on the other side of the Sun, the moons appeared to be moving 17 minutes later than expected. He still did not accept the idea that light wasn't instantaneous, it was some other guy called Rømer that estimated the speed of light. They estimated it as 220,000,000 meters per second. Which isn't super accurate, but impressively accurate based on what they had to go off of. They were about 27% wrong.

I need you to look at the North Pole of Jupiter. It genuinely looks so sick. This is a picture from 2016. There wasn't any light when we sent the camera there, so it's in infrared.

Jupiter's North Pole, captured in infrared by Juno

This whole ordeal has me thinking, why don't I know this stuff? It's not like it's this niche esoteric thing. It's literally the stuff that's around us, in front of us. We probably shouldn't wait for them to be literally in front of us in order to know more about the planets around us, in our solar system. Though it is nice to see them! I like having these visitations from the planets. They inspire curiosity. It's just cool to see!