Japanese astronaut Norishige Kanai has only been in space for three weeks, but he has already grown 3.5 inches taller.<br />That has the astronaut concerned since he must return to Earth in the same seat he used to reach the International Space Station.<br />Microgravity experienced in orbit can do strange things to the human body, including weakening muscles and bones, shrinking hearts, and flattening eyeballs.<br />But Kanai's problem is a bit more difficult to deal with due to the seat.<br />However, astronauts are known to grow by 2-to-five centimeters in orbit, but Kanai has grown by 9 centimeters in only three weeks. <br />
