Josh, Addie and Tracy present a special Valentine’s Day discussion of Dark Matter and the hit novel 50 Shades of Grey. While they get the spelling of Grey wrong, it would have been much funnier had they been right! On a weightier topic, is dark matter made of WIMPs or MACHOs? Hear about the colorful and brilliant astrophysicist Fritz Zwicky who first discovered the so-called dark matter, whose nature still eludes us. Now a new study shows that there is dark matter in the heart of our own Milky Way and in our own solar neighborhood. What does it all mean? There is much more to the universe than we can see. Including, how 50 Shades of Grey became such a hit.