![]() ![]() When the telomeres become too short, the cell's time is up: It can no longer divide, a state of affairs known as "replicative senescence." ![]() Like the fuse of a time bomb, telomeres are long strands of repeating DNA that shorten each time a cell divides. What they learn about aging could benefit everyone, on Earth and in space. With support from NASA, Shay and others are studying the problem. "The reality is, we have very little information about radiation and telomere loss," says Jerry Shay, a cell biologist at the University of Texas Southwestern Medical Center at Dallas. Science is only now beginning to look at the question. Naturally, NASA is keen to find out whether or not the danger of "radiation aging" really exists, and if so, how to handle it. Astronauts on those missions could be exposed to cosmic rays for weeks or months at a time. ![]() These astronauts orbit inside of Earth's protective magnetic field, which deflects most cosmic rays.īut by 2018, NASA plans to send humans outside of that protective bubble to return to the moon and eventually travel to Mars. So far, the risk hasn't been a major concern: The effect on shuttle and space station astronauts, if any, would be very small. Sign up for EXPRESS SCIENCE NEWS delivery ![]()
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