Ray, Chelmsford asked:
Can we tunnel our way from the UK to Australia?
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.