Chris - I think the answer is probably not – purely because of pressure and temperature constraints. Also the fact that the Earth is pretty liquid inside as far as the inner core. Therefore you’d have to contend with huge amounts of pressure, huge amounts of temperature and I don’t think we have the energy or the building materials that would be capable of withstanding that. If you think about it the earth has a radius of 5000-6000km. If we’re standing on the earth’s surface you’re feeling one atmosphere of pressure. The atmosphere above you is about 50km high. If you were going to go 5000km to the centre of the Earth you’d therefore have 100 times the greater amount of atmospheric pressure on you so the pressure just  from the atmosphere would be so huge that just trying to move through that kind of gas would be like running into a brick wall. Very tricky indeed.

Chris - I’ve had a nasty experience because I used to work in a lab where we had lots of -70 freezers. We used to develop various gels and things in those -70 freezers. If you weren’t careful and didn’t put some gloves on when you went into the freezer and grabbed your developer out then your skin could freeze onto the rack. When you removed your fingers and let go then it left a lovely fingerprint on the thing.

That quite literally was a fingerprint because it left the surface layers of skin from your finger. The reason ice is sticky is for that very reason. Ice itself is so cold if you touch it with skin because your body secretes tiny amounts of liquid, sweat, which is a salty fluid onto your skin surface it actually makes your skin stickier. This is why we have it. It’s for grip. If you then touch that onto a very cold ice surface the ice then re-freezes the liquid on your finger. Because that liquid is a fluid and it has got into all the nooks and crannies on your finger it then freezes solid and will form a very tight bond between your finger and the frozen surface, the ice. You get stuck to the surface. If it’s an ice cube – if it’s okay because there’s enough heat flowing through your fingers (usually to re-melt that transient freezing) then you can detach yourself. In the case of a -70 freezer or even colder, people in the Antarctic have to be very careful about this kind of thing. It doesn’t warm up and you can end up permanently frozen to the surface or you can do quite a bad injury. That’s why ice is sticky. You get literally frozen to the spot.

Chris - I think there’s two aspects to this. One is in the same way as the water gets in to  all of the nooks and crannies both in the skin and the surface that you touch – in the same way as when you lick your finger to turn a page – you create more friction between your finger and the surface. The water forms an attachment on that surface.  Blu-tack is plastic. In other words it can deform plastically. It gets into the nooks and crannies of the surface you’re sticking it to and the surface it’s already stuck to which makes it sticky. The other point is that when you press it onto a hard surface the Blu-tack forms a very smooth, flat surface against that hard surface. This excludes air. In order to get the Blu-tack back off the surface you’ve effectively got to break a vacuum. The atmosphere is helping to hold the Blu-tack stuck onto the surface. That’s why I think it’s sticky.

Ben - That’s the same reason why, if you get two sheets of glass and layer water between them and press them together to exclude the air it’s really hard to peel apart even though water isn’t sticky at all.

Chris - Two microscope slides are almost impossible to separate if you put a drop of water and then put the two glasses together. You’ve got to twist them off each other and you can’t pull them apart because the atmosphere is squeezing down on you. Every square metre is feeling a force of ten tonnes: the weight of a London bus. On our bodies every square metre of our body’s got ten tonnes of atmospheric pressure on it. That’s what’s holding your leaflet stuck to the wall with Blu-tak.

We put this to Chris Bishop, Microsoft Research

That’s a good question. CDs and DVDs work in slightly different ways but they have something in common, which is that like all computer storage systems they use binary. All the information’s expressed in terms of strings of 1s and 0s or 'on' and 'off.' In a hard disc that’s represented magnetically. Each bit is represented by a tiny magnet built into the surface of the hard disc and if it’s facing north-up it’s a 1 and if it’s south-up it’s a 0. The head that reads this information can also flip the magnets and so it can write information to the disc. The CD is rather similar. It also has these 1s and 0s but they’re represented rather differently. They’re represented by little pits. When a disc is written a laser burns little pits into the surface of the disc and another laser can read back those points. If there’s a pit there might be a 0 and if there’s no pit it might be a 1.

We put this to Demis Hassabis of the Institute of Cognitive Neuroscience

Demis - Well at the moment we’re very far away from that kind of technology. So far All the technology that is being used in neuroscience at the moment is passively reading the electrical activity the brain is creating itself, rather than actually influencing it the other way. I do know of some rather experimental studies that have been done trying to connect chip board to rat brains and trying to control the way they navigate. As far as I know those are very experimental at the moment. Nothing’s really practical that’s come out of that yet.

Chris - I believe there was a researcher in Europe who showed if you supply or apply an intense magnetic field to the head while they are learning things it helps them remember them better. He was doing this with word learning. He was doing this with students to sleep with a magnetic field round their head. I think it improved their ability to learn, probably because the brain’s an electromagnetic organ.

Demis - There may be ways. You could do it neuro-chemically as well with some drugs. There are probably ways of changing and up-regulating entire systems in the brain but that’s very different from influencing a specific thought or getting them to specifically think about a key episode, as well.

We put this to Chris Bishop from Microsoft Research

Computer processors have been doubling in speed every two years for the  last fifty years or so and it’s been driven by something called Moore’s Law which says the number of transistors on a processor keeps doubling every two years. As the transistors have got smaller and smaller we’ve fitted more on the chip. We’ve started to run into some problems. One of the problems we’re hitting already is to do with the heat density that’s produced by all these transistors in a tiny space switching on and off. Right now the heat density on a chip is equal to that on a hotplate on a cooker. If we carry on the way we’ve been going then in ten years’ time that heat density will equal that of the surface of the sun. We have to find a new way forward. The main approach that we’re adopting is to do what we call parallel computing. Instead of trying to make each individual processor run faster we have several processor s side-by-side, all working on the problem together. Using that technique of parallel processing we should be able to continue to get processors collectively to run faster and faster and to continue this doubling every two years for a good many years if not decades to come.