Hey everybody, welcome back to X-Lanacom 5, the podcast where we take the questions you always wanted to ask and talk about them in a way that's easy to understand. We're your hosts, I'm Tim. And I'm Kevin. So Kevin, today we're talking about a planet that lots of five-year-olds love, and that is Jupiter.
What do they mean when they say Jupiter is a gas planet? For example, could a rocket be shot through it? Does that make Jupiter a really light planet? You're right.
Jupiter is a gas planet, which means it lacks a well-defined solid surface. And it's kind of weird to think about it, so let me try to explain it this way. If you have a scented candle, you know one of the things that comes in a glass container? Well, when you light it and let that top layer of wax melt, and then you look at it from it just kind of meld together.
And Jupiter's atmosphere works kind of the same way. The top layer is gas, and then you go down further, and it's a cloudy mix of gas and liquid, and even further, and then it's all liquid, and finally, if you go that far enough, it is most likely a solid. Very interesting. That's a great way of explaining it, like I'm five.
You still haven't fully answered my question, though, about shooting a rocket through it, but let's take one step back. Why is Jupiter so fascinating? Is it because it's the largest planet in our solar system? Totally.
It's one of the reasons that I'm so fascinated by it. Jupiter is the fifth planet from the sun, and the largest in our solar system. But it's also the third brightest natural object in the Earth's night sky after the moon and Venus, so it's been observed for a very long time, all the way back to prehistoric times. And as we have described, it is a giant gas planet, but it has a mass of more than two and a half times that of all the other planets in the whole solar system combined.
I see. So not exactly light, but could you shoot a rocket through it? Okay, okay, that question. So no, no, probably not.
You know, now think about as you kind of like swim deeper into the water, you know, you will eventually feel that pressure on your ears. So imagine that on a big planetary scale, which scales everything up exponentially. The deeper you go, the more stupidly high the pressure gets. So even if you were to try to shoot a giant rocket through Jupiter without going through its core, it would probably be crushed under all that immense planetary pressure.
Hmm, okay, well, how about the slightly different nuanced question then, which is, could you land a spacecraft on it then? Ah, yes. So it would also be pretty impossible to land on it. Again, think of that candle analogy.
You kind of sink into it until you just couldn't go any further. Jupiter also has a rocky core, but like we just said, you wouldn't manage to get past the pressures and temperatures of that atmosphere. Jupiter is primarily composed of hydrogen, whereas also helium constitutes one quarter of its mass and one-tenth of its volume. Now, there's a giant red spot on Jupiter, and it's so distinctive, so we pay attention to it.
I believe it's a storm that you see in the atmosphere, but why does that storm just keep going and going? It doesn't really disperse over time. Ah, yes, the great red spot, like I said. It's a giant storm, and it has been around a very long time.
In fact, it has been observed since at least 1831. Some people call it the GRS for the great red spot. So the Hubble telescope has been used to observe that the GRS is getting smaller, actually, by about 580 miles every year, along its major axes, and its shape is changing from that of an oval to kind of a circle. And at a current rate, the storm is expected to become circular in a few years.
The vortex could completely disappear or grow larger, since the fate of such storms of this scale are really difficult to model and predict precisely. Same thing for storms on Earth. Now, speaking of circles, they say that Jupiter is not entirely round. Well, yes, because of its rapid rotation, Jupiter's shape is an oblate spheroid.
Meaning it has a slight but noticeable bulge around the equator. Also, this rapid rotation means the outer atmosphere is divided into a series of latitudinal bands with a lot of turbulence and storms along their interacting boundaries. A prominent result of this is that great red spot which we just talked about. So next time you look at Jupiter, you notice the amazing horizontal bands.
Now, we've been to Jupiter a couple times to observe it. And a few years ago, NASA announced that the Juno mission that had reached Jupiter was one of the hardest things that they had ever done. Why was that? Oh, so there were a few expeditions even before Juno.
I think Pioneer 10 was the first spacecraft to visit Jupiter in 1973, and then Voyager and later the Galileo orbiter in 1985. And the latest probe to visit the planet, like I said, Juno. NASA's Juno mission arrived at Jupiter on July 4th, 2016, with the goal of studying the planet in detail from a polar orbit, and it's still active today. So what made it so hard?
So the mission used a relatively small launch rocket, so they had to use Earth's gravity to slingshot it towards Jupiter. It also has the largest set of three solar panels of any deep space probe ever launched, and that slingshot is a MacGyver called Gravity Assist. So the spacecraft was given a boost in speed of more than 8,700 miles per hour through said gravity assist. Wow, that sounds really fast.
Well, yes, definitely it's fast, but actually not that fast compared to when Jupiter's gravity accelerated the approaching Juno's spacecraft. You know, at that point, it reached something like 130,000 miles per hour. Well, that's good to know. We'll definitely pay attention to final details now when we look up at Jupiter.
Did you learn something new? If you did, send us an email. We are at eli5thepodcast at gmail.com. As always, thank you for your questions and comments and suggestions, and thank you to the community at r slash explainacom5 as well.
We will see you all next week.