Chris - I know this because people have told me. My friend who I mentioned earlier was blind from birth and he tells me that his dreams were mainly words and sounds. In other words the kinds of things that you’re exposed to that you have experience of experiencing. He would just experience those.

Chris - The answer is that in space there’s nothing to stop the radiation and so there’s a million mile an hour maelstrom of cosmic radiation which is streaming off our own sun. If we didn’t have the magnetic field of the Earth to deflect it away then it would be basting us in radiation. It would also be plucking away our water and our gases on our planet and we’d end up like Mars ultimately did. It isn’t a safe and nice hospitable place in space. It’s not just because of the use of fusion.

Steve - Nuclear power plants aren’t doing fusion, they’re doing fission which is splitting big nuclei up: uranium. In a nuclear power plant you only use a very small fraction of the uranium so there’s something like 50 times more energy left in there that we’re unable to tap except through what’s called fast breeder reactors which we don’t currently do.

Chris - How do they work?

Steve - This is a long question. They work by using the fast neutrons from nuclear reactions, from uranium, to attach to the inert part of uranium (uranium 238) to make plutonium. Plutonium can fission like uranium 235. That’s a complicated answer.

Steve - The sun’s doing fusion very slowly. It doesn’t have to do it any faster to keep itself held up. If the sun did fusion faster it would expand and then the fusion would go slower and it would contract back down again. If the sun was doing fusion too slowly it would contract until the fusion got fast enough to hold it up. The sun is just self-regulating and that’s why it’s going to last 5 billion years.

Steve - With the current designs we have fusion power stations. These are conceptual. We haven’t built one yet. With the current designs we burn deuterium which we extract from sea water and we burn lithium which you get from salts. There’s millions of years-worth of this fuel. The by-product is helium which you can put in kid’s balloons if you really like. They don’t have any long-lived wastes from this. It’s really an ideal way to make energy.

Kate - ITER as Steve pointed out is a completely different device. It’s a big magnetic donut and it confines plasma for a length of time whereas the thing about lasers is the Reactor would be slightly different. You have to inject these fuel pellets and compress them. In order to support a 4GW reactor you’d have to do that four times a second. The designs of the two system s are very different. That’s not to say we don’t have overlap and they’re not complementary. They are, we have some of the same technology challenges.