How would a fourth dimensional being appear to humans? "It would look just weird" is one way to answer the question 'How would a fourth dimensional being appear to humans?' But it's more complicated than that - theoretical cosmologist Andrew Pontzen describes how objects are viewed from one dimension to another, and how it might affect parking spaces. Also on the programme: our panel of experts discuss bubble experiments, a theory that the Black Death was a virus, space elevators, algae as a biomass fuel, what affects the speed of digestion in our gut, a short definition of dark energy and the question is it true our DNA has alien properties? With Helen Czerski, department of mechanical engineering, University College London; virologist Jonathan Ball, University of Nottingham; and cosmologist Andrew Pontzen, University College London. Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk. (Image: Stripes and points of light, one guess what a 4th dimension might look like, Credit: Thinkstock)