Space is as mysterious as it's unruly. Its size remains inconceivable. Its properties are an enigma for the most part.

To think that humans have developed sufficient technology to navigate certain parts of space with precision is astounding, but even more astounding is the fact that there's literally a place up there called the International Space Station where astronauts are staying to study space, or what's it's like to be in space.

Unfortunately, being in space affects the human body in critical ways. The most stunning example is Retired astronaut Scott Kelly, whose DNA changed while shacked up inside the ISS for 340 consecutive days.

NASA Twins Study

NASA was able to determine these changes thanks to astronaut Mark Kelly, Scott's twin, who stayed on Earth. NASA's Twin Study research involved genetic sequencing to observe their individual responses to the spaceflight environment. The full integrated results between the twins is scheduled for release this year, but initial findings suggest that Scott's telomeres lengthened after his stint in space. These are caps at the end of DNA that protect chromosomes. Surprisingly, though, it shortened within mere two days when he landed back on Earth. The space agency thinks this could be because of Scott's strict diet and exercise while in space.

NASA is also trying to determine whether a "space gene" could have been activated while Scott was in the ISS. In total, 7 percent of his DNA apparently had changed permanently, but researchers are still trying to determine in what ways.

Why Your DNA Might Change While In Space

There are a number of factors that might lead to changes in DNA for people who spend a great amount of time in space, where the body succumbs to different properties and rules of physics it wasn't accustomed to while on Earth.

Such factors that affect genes include oxygen-deprivation stress, mitochondrial stress indicating damage to the cell's power plants, increased inflammation, striking nutrient shifts, DNA damage and repair that may be linked to caloric restriction and radiation, and more, all of which Scott had experienced. Again, it's worth noting that some of these returned to their normal states once he went back to Earth, but it's still a fascinating indication of how space affects DNA.

Moving forward, understanding how space travel affects the body, even down to the DNA level, is crucial information if humans want to send astronauts to Mars, which, suppose it comes true, is the farthest we will have traveled to after the Moon.