The 'twins study'.

• Position: SPACE - Brief article

How are humans affected by spending a long time in space? To find out, NASA turned to twin astronauts Scott and Mark Kelly. While Mark stayed on Earth, Scott spent a year aboard the International Space Station, returning in March 2016. He and Mark underwent a series of medical tests before and after the mission. The result? A year in space affected the composition of Scott's DNA, slowed his reflexes, and even temporarily made him two inches taller. And the ends of Scott's chromosomes--which typically shorten with age--actually lengthened, before returning to normal back on Earth. The study offers important...