Do cosmonauts and astronauts risk aging prematurely during space travel? A new study by NASA looks into this, using twins to study the effects that space has on the body. They are theorizing that cosmic rays in space affect our cells in a way that causes us to age faster. This is in contrast with Einstein's Thoery of Relativity, which would mean that someone in space would actually age at a slower rate than someone on Earth. Here's a video covering the new study: