This week, we're traveling halfway around the globe using the most direct route we can think of-- through the center of the Earth. To help us along the way, we consult the mind of Professor Markus Deserno of the department of Physics at Carnegie Mellon. It turns out, even after turning down the thermostat in the Earth's core (so we don't melt during our journey), we run into a few problems, most of which are not obvious.