Sorry Mary, but we can't believe it's true either. I imagine that any spinning is more to do with the twist of the cotton that you hang the key on than anything else. There's probably a bit of gambler's fallacy kicking in there. You're expecting the right answer and therefore the result happens.

I don't know whether there is a direct relationship between pressure and headaches. If anyone listening knows anything about a link between migraines and weather, I'd be very interested to hear about it. My email is chris@thenakedscientists.com. One thing that does occur to me is that if you have high pressure, then usually that's associated with a warm day. When people get very hot, they get dehydrated and a fierce headache. That could be possible.

It's a bit of a fallacy that outer space is really cold. It actually depends on how close you are to the sun. One problem is that it doesn't feel cold like it does on the Earth. There's no air around you to conduct heat away from you or towards you; everything is done by radiation, passing light from one object to another. Light from the sun falls on a body and heats it up. For satellites up in space around Earth, we actually cover then in reflective material to keep them cool, and insulating material to keep them hot. If they're in the sunlight, they actually overheat so we put reflective material on there to reflect the light away. When they're in the Earth's shadow, we can use heaters to keep it warm. When you get further and further away from the sun, it gets really cold. The outer space around Earth is around 20 degrees Centigrade. If you go out to Pluto, you're probably looking at around minus 220 degrees Centigrade. So it depends on exactly where you are.

I completely agree with you, John. The point is that here on Earth we see organisms the breathe methane. We see organisms that breathe and produce hydrogen as a waste product, and we see organisms that produce hydrogen sulphide as a waste product. In fact some of the first organisms on Earth were methanogenic bacteria. They produced methane by taking simple carbon building blocks from the environment, jamming them together with four hydrogens and making methane. Some scientists from Japan found some of the world's oldest bacteria locked away inside tiny bubbles inside quartz. Life can come in all shapes and sizes, and evolution can pattern us and puts pressure on us to become adapted to our environment. On a different planet, things could be completely different and we have no reason to assume that alien life would look or even metabolise anything like we do.

I would say that you actually share more than 98% of your genes with a chimpanzee. I suspect that virtually all of the genes in the human genome also have counterparts in the chimpanzee genome. The most likely explanation for the fact that we are so obviously different from chimpanzees is the way in which these genes are controlled and the way they are switched on and off, and the length of time for which genes are active. You share 50% of your genes with your daughter because she's obviously inherited one genome from you and one genome from her mother. We all have two genomes in our bodies: one from our mother and one from our father, but there are counterparts to all of your genes in the genome that your daughter has inherited from her mother. If you compare a banana with a human, just over half the genes in a banana will do the same job in a banana as they do in a human. However, the genes themselves will not be the same letter for letter; they just perform the same function. In contrast, when you are talking about the genes you share with your daughter, you are not asking how many of the genes have the same function (which is 100%), you are asking how many of those genes are absolutely identical, letter for letter. The probability that any one of those genes came from the father is 50%, and the probability that a gene has come from the mother is also 50%. This is why you share 50% of your genes with your daughter.

I should make it plain from the outset that I don't really understand why people go bald. I'd probably be very rich if I understood that! Baldness is what is described as a sex limited condition rather than a sex linked condition, which means it tends to affect one sex more than the other. In this case it's obvious: it affects males more than females. But it's not a straight forward inheritance of a gene on the Y-chromosome, for example, that leads to baldness. The genetics and inheritance patterns are more complex than that, otherwise people would have been able to follow these inheritance patterns through families and understand more about the genetics of baldness. So we're not there yet, but we have some useful information.

I'm not sure I can comment on the idea that blonde and ginger people will become extinct, as it's the first time I've heard that. But interestingly, some people have speculated that the Y-chromosome that we were talking about earlier may disappear completely. The Y-chromosome has degenerated during the evolution of the sex chromosomes. Some people have speculated that in 10 million years it will have disappeared altogether. Obviously that is of some concern to males, but suffice to say that natural selection will act against anything that prevented there being males within the population. So for the Y-chromosome to disappear, another gene would have to arise to make a male sex. But I really can't comment on the extinction of blonde and ginger people.

There are obviously different components to evolution. There's a component of genetic change and genetic change is still going on. There's also the component of natural selection whereby certain adaptations are selectively advantageous or disadvantageous. There's an argument that we've stopped evolving as humans because we've removed those elements of natural selection. Other people are speculating that we're evolving in different ways; psychologically and so on rather than physically. But it's an open question.

That's a very difficult question to answer. I'm not aware of there being any evidence for learning of particular skills then becoming hard wired in the DNA. This was a theory that was quite popular in the early twentieth century that perhaps things could get hard wired into the DNA, but I'm not sure there is a mechanism for that to occur.