S1E86 - Why Your Body Needs Gravity

Does space travel make astronauts younger?

Professor Hannah Fry and Michael Stevens explore Einstein’s twin paradox, time dilation and NASA’s famous Twins Study with astronauts Scott and Mark Kelly.

After Scott Kelly spent 340 days aboard the International Space Station, he returned milliseconds younger than his identical twin. But microgravity had also affected his eyesight, bones, blood, gut microbiome, body temperature, genes and telomeres.

So what exactly happens to the human body in space, and which changes remain after astronauts return to Earth?

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