Astronauts who take long trips to space return with brains that have floated to the top of their skulls

This small population of space travelers has given researchers a rare look at what happens to the human body when it’s able to spend significant amount of time outside the downward pull of the Earth.This week, a study on one of the largest groups of astronauts yet—a whopping 34 participants—was published (paywall) in the New England Journal of Medicine.