Flies normally fly during the day, which is why they have very good eye sight. They roost in nooks and crannies and so on ready to get a meal from you. The carrot fly, which is a pest of carrots, actually roosts in hedgerows and we devised a means of passing a disease to them in the hedgerow. Unfortunately, unlike the mosquito repellents, that's a very long way from commercial development.

That's a very good question, and in fact some work has been done on that quite recently. It turns out that the Venus fly trap has two disc-shaped leaves that invert themselves when an insect touches them. This happens very quickly, and they discovered this by doing time-lapse photography. The scientists who discovered it painted ultraviolet dots on the Venus fly trap so they would show up when they shone UV light on to the plant. They took 400 photographs per second while triggering a Venus fly trap and could map what happened. The analogy they used is that if you take a tennis ball, cut it in half and then turn it inside out, it will sit there quite happily. However, if you come along and just touch it very lightly, it pings back again.

The reason that cabbage goes a nasty brown colour when you cook it for too long is because it changes the chemical nature of the green stuff in the leaves, or the chlorophyll. If you put bicarb in there, it changes the conditions by making it more alkaline. This means that the magnesium ion that would pop out of the leaves in normal water, stays in there.

The answer is probably no, because the Big Bang was 14.9 billion years ago, and scientists mainly study that by looking at left over radio waves. In contrast, the Stardust comet mission is going to tell us about the formation of the solar system, which is about 4 and a half thousand million years ago. So it probably won't tell us anything about things at the beginning of the universe.

It's all down to the momentum of the thing concerned. The Stardust mission comet Kat spoke about earlier was actually travelling thousands and thousands of miles and hour faster than the probe was, and the tiny particles it was throwing off were capable of destroying that probe. And this is all down to momentum. The momentum of something is the mass of something multiplied by how fast it's going. That's how hard something slams into you. So it doesn't actually matter how heavy or big something is because the faster it hits you, the harder it hits you. If you drive into a fence at 60 miles per hour, the slamming effect will be the weight of your body multiplied by the speed that you're going. If you're hit by a bullet, although the mass of the bullet is much less than you hitting the fence post, it's going a lot faster. The average bullet coming out of a pistol is going at around 700 miles per hour, which is a lot faster than someone in a racing car. As a result, the momentum of a bullet is much higher. The reason bullets cause such a problem is because although they go in and make a very small entry wound, the shock wave of the bullet hitting your tissues rips you apart internally. That's why if you look at someone who's been shot from the front, they don't look too bad until you look at them from the back where there's often a very big exit wound. This is because as the bullet goes through, it compresses all the tissues it passes through and pulls them to pieces. It's like being hit with a fence post but much much harder.

That's a very good question. I think that it's not just attraction that can give you bites. It can depend on whether you show a good response when the fly or mosquito gets there, such as if you notice it or not and swat it away. But in terms of attraction, you can take certain things in your diet. If you have very strong plant smelling chemicals in your diet that come through the skin, such as with garlic, then these can put off some flies. They're obviously carnivorous, so they don't want to come to somebody smelling very strongly of plants. However, it's not very reliable. Although quite a lot of the mosquito repellents we use commercially are based on that kind of effect, they're really not that good and the mosquitoes can break through because they can see the attractant chemical through the ones we try to mask ourselves with. That's why it's been very important to look at individual human beings to find out how it is that some of us are actually repellent to mosquitoes and other flies.

Many flies, which includes the mosquito and the biting midge, use carbon dioxide, heat and various other chemicals that are quite commonly produced. But they will also use specific compounds to see human beings. For example, the malaria mosquito can find a human being in the middle of a very large group of cows, which are oozing carbon dioxide and heat. It uses specific chemicals to find that human subject. It will be the same for the flies that are annoying the friend in Melbourne. These insects are able to perceive what kind of potential host they've got, even if it's not blood they're after, just the mucus around our eyes and mouths.