One of the most beautiful sights I've ever seen through a telescope is looking at the planet Saturn. When you look through a small telescope even at Saturn, you can see this tiny little ball with these tiny little rings around it. Even through a pair of binoculars, you can see the rings of Saturn. 


In fact, the first picture in our gallery shows roughly what it would look like if you were looking through a small telescope. These rings of Saturn were observed even by Galileo when he first turned his telescope to the sky.  But they weren't understood until later astronomers carefully observed Saturn and noticed that these weren't just nearby moons, large moons, but instead were actually a system of rings.  


Now Saturn isn't the only planet that has rings.  In fact, all four of the gas giants Jupiter, Saturn, Uranus, and Neptune all have some form of rings.  But those rings around the other planets were only discovered in the past 30 years or so using sophisticated equipment, whereas Saturn's rings are plainly visible to anyone who looks through a telescope. 


Now, in addition to the rings, here's the second picture in the gallery I have to say is from a recent space mission, Cassini, that was sent to orbit Saturn and take up close pictures.  And these are the most astounding pictures I think in the whole solar system of Saturn up close and seeing Saturn's rings from many different perspectives.  And we'll see a couple of these pictures in the gallery. 


One of the things I want you to notice in this second picture in the gallery is not only Saturn's rings in this beautiful image, but also these other tiny dots of light around Saturn.  You may notice just little tiny specks here and there.  And those are Saturn's moons.  Saturn has lots of moons, so does Jupiter, but Saturn has a lot. In fact, Saturn has over 30 moons that go around it.  Now one of its moons in particular we'll talk about later is a really big moon called Titan.  But there are many smaller moons that orbit around Saturn. 


Let's take a minute though and think about the rings of Saturn these rings are truly astounding and it's tempting to think what they might be because they look like they're solid disks.  In fact, the third picture in the gallery shows it up close and edge on.  They look like solid disks, but they're not in fact solid at all.  Instead, they are made up of tiny little particles – well, some are tiny, some are a little bit bigger.  Some of the biggest maybe are the size of a house.  But on the scale of our solar system that's really tiny.  Even a house is tiny in the scale of our solar system.

So these are small chunks of ice and rock that are all orbiting around Saturn.  But it looks so smooth when we look at it, but it's not.  It's not necessarily as smooth as you might think. 


So let's take a look here, this third picture shows Saturn's largest moon, Titan, in the foreground. And then you can see just how thin Saturn's rings really are, which is truly astounding.  This is so thin.  The analogy is like if Saturn's rings were a pizza, if you were to shrink Saturn's rings down to a pizza, it would be so thin that it'd be the width of a single hair.  But in actuality, Saturn's rings are really wide across like 21 Earths could fit across Saturn's rings, okay. But the height, the thickness of the rings is just 100 meters - 300 feet.  So something that's 20 Earths across, but just 300 feet, a football field, or, you know, high.  That's truly astounding.  


And this Cassini spacecraft has been able to capture up close pictures of the rings themselves.  And here's one of my favorite pictures.  And it kind of gives you a sense of the texture that's a part of these rings because it's tempting to think that these rings are a solid disk, but we know that there are these smaller particles. 


At the top of this fourth picture in the gallery, you can see more texture on the ring.  See right up here.  You can see that it looks like little mountains in the ring.  And what can happen is as the moons of Saturn are going around, they can disturb the rings.  The gravity of the moons can actually cause the rings, little parts of the rings to go up and down and move around a little bit. And that's what we're seeing in this particular picture. What it illustrates though, you can even see the shadow of those little mountains. But it illustrates though, is just how finely grated, how small the particles are, that are going around.  See what it looks like it's all very smooth, and it’s going around the surface.  You can see it's actually made up of really millions and millions of small particles. Very, very cool. 


These ring systems are incredibly complicated.  In a sense, what it is is millions of tiny little moons that are all orbiting around Saturn and interacting with one another.  So the gravitational interactions are incredibly complex.  And we see really cool patterns emerge when you look at these rings up close, and scientists are still trying to understand those relationships and those patterns with this new data that they get from these spacecraft up close. 


One of the other really cool things about Saturn is this large moon, Titan. And the fifth picture in our gallery shows a picture up close of this moon, Titan.  One of the reasons that Titan is an interesting place is because it has a relatively thick atmosphere.  And when there's an atmosphere, there's the potential that there could be liquid, or warmth, on the surface of the planet.  In this particular case of Titan, there's an interesting story that goes with it.  


The Cassini spacecraft, the spacecraft that's been taking these pictures of the rings of Saturn also contained a small lander probe called Poigan, named after another famous astronomer.  And this probe went in and landed on the surface of Titan and took pictures the whole way down.  So we actually have one or two pictures from the surface of Titan.  And it was able to kind of see, you know, observe the landscape around as it landed, and make some measurements of the atmosphere as it went through. 


So here are the some of the things we know about Titan. And while Titan has an atmosphere, it's still very, very cold on the surface of Titan.  And so it's so cold that there's liquid there, but it's not water liquid.  Instead, it's like a methane liquid that's similar to gasoline.  So it's crazy.  But on the surface of Titan there are actually, it appears lakes, maybe even whole oceans, that are composed of a gasoline like material.  It just goes to show that - oh, and not only that - but there's surface liquid there, even rain and snow of this gasoline like material.  It goes to show just how different and seemingly bizarre these other places in our solar system can really be.


Alright.  We'll see you next time.



Modifié le: lundi 2 octobre 2023, 12:25