 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. By 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 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 shape like potatoes, some that are huge sponges made from we think a coral kind of substance. There's one moon, a memas that looks like the Death Star if you've ever watched Star Wars. But one of the moons in particular called Cassini's eye, Enceladus. At first glance it looked like a cold and lifeless icy body but then Cassini caught the moon in silhouette and it revealed something spectacular. Geysers erupting through Enceladus' 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? Well we don't know. Most of Saturn's moons including Enceladus 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 an 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 been brought closer to home. Our planetary neighbourhood now feels that little bit smaller but we should not forget that sending a 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 metres on the scale of this lime or in reality 1.3 billion kilometres. 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.