About 400 years ago when Galileo looked at Saturn through his handheld telescope, he actually thought at first it was a very strange object. He could see the rings but he didn't know what they were and it looked like a face with two ears on either side. 400 years later in 1997, NASA launched the Cassini spacecraft on a mission to Saturn, allowing us to see it like we'd never seen it before. I'm actually being at these other planets you can learn so much more and really study them in detail. Unlike the rocky inner planets of our solar system, Saturn is a gas giant. It's made from mostly hydrogen and helium, so you couldn't really land on its surface. The gases that compose Saturn are lighter than water, so if you could find a swimming pool big enough to put Saturn in it, it would float. Of course, what really makes Saturn stand out from the other planets is its spectacular rings. So Saturn's rings are very very thin in comparison to how wide they are. They're very thin so if you look at them, Ed John, you can barely see them. And they're made from a mix of things, mostly from ice, water ice, which means that they're very reflective and that's why we can see them from Earth. Cassini has also revealed a whole army of moons orbiting around the planet. We thought that there were about 20 moons, but Cassini's shown us there are at least 60 moons and counting, and these moons are incredible in themselves. They range completely from some that are shaped like potatoes, some that are huge sponges made from, we think, a coral kind of substance. There's one moon, a me-mass that looks like the Death Star if you've ever watched Star Wars. But one of the moons in particular called Cassini's Eye, Inceladus. At first glance, it looked like a cold and lifeless icy body, but then Cassini called the Moon in silhouette and it revealed something spectacular. Geezers erupt him through Inceladus' icy crust, shooting water vapor out into space. This water vapor has to come from somewhere, so if it is coming from underneath the icy crust, is there a liquid ocean of water underneath while we don't know? Most of Saturn's moons, including Inceladus, are tiny, but one is a giant, Titan, nearly half the size of the Earth. The moon is covered with a thick atmosphere that shrouded its surface. But Cassini carried a probe built by Issa, called Huygens, that descended down through the atmosphere and onto the surface of Titan, revealing and intriguing looking landscape. There's river valleys and dunes, and it's very much like a young Earth. If you could go to Earth five billion years ago, this is kind of what Titan looks like now. There's liquid oceans on the surface of Titan, but they're not liquid water, they're liquid methane, and methane's a gas on Earth, but because it's so cold at Titan, so far away from the Sun, the gaseous methane on Earth is actually a liquid on Titan. With spacecraft like Cassini, the distant wonders of our solar system have been brought closer to home. Our planetary neighborhood now feels that little bit smaller, but we should not forget the sending of spacecraft to another planet is no easy feat. What I've got here is a scale model of the solar system using different foodstuffs to represent the different planets. Here we have the Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Now this gives you a rough indication of how big the planets are in relation to each other, but it doesn't tell you how far away they are from each other. I really want to show you this because then you'll see how amazing it is that we sent a spacecraft from Earth to Saturn. Now if this was Earth, and if Saturn was this big, let me show you where Saturn would really be. I've just passed Mars. There goes Jupiter. It would be here, that's 550 meters on the scale of this line, or in reality 1.3 billion kilometers. I absolutely love working with the Cassini mission. I've learnt so much in the time that I've been on it. It took seven years to get to Saturn, but it gives us data every single day. You just don't know what tomorrow is going to bring. We hope you have enjoyed this video and for more videos go to FreakPhysics.com.