Space does not only defy gravity and make astronauts weightless, it seems that there are internal benefits to the human body, too. According to NASA astronaut Scott Kelly's DNA, after a year in space can change and affect genes.

Scott Kelly's NASA space travel can impact a person's body. The study done on Kelly's chromosomes are called the Twins Study.

The research focuses on the effects of space travel between Scott Kelly in and his identical twin brother Mark Kelly who is also a former astronaut, as reported by USA Today. Before flying out into space, both brothers shared their biological DNA. After Scott arrived since spending a year into space and Mark was on Earth the whole time, the samples were taken again.

In a funny Tweet, according to Mark, Scott Kelly's height added a couple of inches more but the Twins Study showed deeper results. It appears that his chromosomes lengthened. Researchers on his DNA notes that it could be because of his increased physical exercise and minimal calorie intake. After his journey in space, they found that his chromosomes shortened. This is an outstanding study because the end of his chromosomes, called talomeres, usually decrease in length as a person gets old.

Kelly's cognitive skills slowed a little when it comes to speed and accuracy, after the mission. His bone formation also slowed during the second half of the trip. And there are two dominant bacterial groups that were rife in Scott when he was in space. While there are more findings, it was his telomeres that took the spotlight because of its association to longevity, as reported by CNET.

According to Susan Bailey, a radiation biologist at Colorado State University that currently works with NASA, Scott Kelly's telomeres contradict with their original thought which was long-term space travel can cause stress. And stress shortens telomeres. His DNA is allegedly a sneak peek into the fountain of youth.

Watch the video of Scott Kelly below, reviewing his space travel: