How does a mobile phone mast work? What affect does living in space have on the human body? Could tractor beams become a reality? We take on these space age questions in this week's show as well as reveal the land area of Earth, why people in the Southern Hemisphere don't walk on their heads, why hair looks darker when wet and why alcohol makes you feel happy. Plus, we investigate what would happen if we drilled to the centre of the Earth! Like this podcast? Please help us by supporting the Naked Scientists