Getting to experience space travel and what life is like in outer space is simply a dream for most people. But, this dream might turn really badly for most, if not all of us humans.
After spending a year on the International Space Station, astronaut Scott Kelly returned to Earth shorter, more nearsighted, lighter, and with new heart disease symptoms that his identical twin brother did not experience. (Mark Kelly, a current senator from the United States, also spent some time in space.)
Since almost 1,000 of Scott Kelly's genes and chromosomes functioned differently, even their DNA differed. (On the plus side, because of how quickly the space station circled the Earth that year, he aged around 9 milliseconds less.)
Although not all of these side effects disappeared after a few months, the majority did, highlighting the potential health risks of space travel, many of which are yet unknown. These will intensify on challenging upcoming missions, like NASA's planned Artemis mission to the moon and eventual missions to Mars.
