Guide to the Galaxy

Chris Lintott and Maggie Aderin-Pocock are joined by American astronomer Neil deGrasse Tyson, who presents a guide to the most detailed three-dimensional map of the galaxy ever made. The research that has gone into the chart has revealed a much larger quantity of stars than was previously known, including several with very strange qualities. Plus, a look at how the Milky Way may already be colliding with another galaxy.