It’s not easy to become an astronaut, it even more difficult to find two astronauts who happen to be identical twins. When you do find them, it is only natural that some sort of scientific experiment takes place. NASA is currently planning an experiment involving twins, Mark and Scott Kelly, to monitor how living in space affects the human physiology. Scott will be sent to live in the International Space Station for a year, while his brother will stay on Earth.
NASA explained it will be looking for research proposals that focus on specific biological attributes in particular, including the effects of space on genetic mutations, protein levels, the levels of other biological molecules, and differences in astronaut psychology between Earth and space.
What they will not be doing is officially testing the “twin paradox”. The thought experiment that proposes people in space should age slower than people on earth. It’s a shame that this aspect of relativity will not be tested, it would be nice to see the effects of relativity on the human body in action.