Walkabout The Galaxy

Neptune, as the outermost big planet, has an outsized effect on the countless objects in the Kuiper belt in the distant reaches of the solar system. We take a look at how the orbits of Kuiper belt comets today can teach us about Neptune's orbit 4 billion years ago, which is pretty cool if you think about it, and even if you don't. We also get a clue that cosmic rays may come from supernovae, including one in our own galactic back yard. Get all this and top quark trivia on this episode of WtG.