If you take Saturn with its rings, Saturn is not a perfect sphere. This is because it's spinning and its mass gets thrown outwards. This makes it a bit wider than it is tall. Because of this, there's a concentration of mass around the centre, which means that stuff is more attracted to the area at Saturn's equator than anywhere else. So even if you started of with a spherical sphere of debris around the planet, then eventually as they bump into each other and jostle each other, it will all settle down into a ring. This extra mass around the centre provides that extra bit of pull and forms rings instead of a sphere. This is exactly the reason that the planets in our solar system form the planar structures that they do. This is also why moons tend to be in the equatorial plane. It's all the same theory.

They're not really very accurate and you can get around them. It's called glavanic skin response. A lie detector works by measuring changes in skin conductance on the basis of sweating. It uses the fact that when you lie, your skin usually goes up in its conductivity because you sweat, and you sweat because you're nervous. This is also linked to blushing. There's another group of researchers who in the past few years have been looking at another way to tell if you're lying, which is studying closely the blood flow across the face. Although this is probably still undergoing tests, they found that when people tell a lie, the blood flow around the eyes specifically changes and increases blood flow. Even if your eyes aren't sensitive enough to pick it up, a clever camera can. So you can look at the heat or thermal changes in someone's face and tell whether they're trying to hide something. This would be useful, say, at the airport. If someone's checking in and says no when asked if there's anything in their bag, this may be a way to flush out the liars without having to do anything invasive.

When you put particles into the air, such as from cars, industry and volcanoes, the particles reflect some of the sun's rays back into space and stop it coming through into the atmosphere. The sun is the key source of warming and energy input into our planet. So actually in real terms when you have a big volcano, despite the fact that it releases an enormous amount of heat, it releases an enormous amount of ash. That correspondingly cools the planet. Most people might think that volcanoes would heat the planet up, but they actually cool it down for quite a long time. A recent piece of research in the journal Nature showed that Krakatoa, which blew up over Indonesia about 100 years ago, still has a legacy living on in the oceans today. Over 100 years later we can still see a cold body of water and lower sea level because of that.

The basic problem with the ocean trenches, we're talking 9, 10, 11000 metres, is that it's incredibly hard to sample animals from down there. People have only been down there once and they saw fish. There are no nets that can go that far down but so far four species of fish have been found in these trenches but 90% of the creatures down there are holothurians, which are basically tubeworms. So there is a lot of life down there and there are also bacteria that live on the sea floor. The problem is that we haven't found most of it yet. It's not that it's not there; it's just so difficult to actually see it.