NASA astronaut bizarrely grew 2 inches taller after 340 days in space

Space does some strange things to the human body, but there has been perhaps no stranger occurrence than when one now-retired NASA astronaut somehow grew two whole inches during his stay on the International Space Station (ISS).

If you've been following the events of stranded NASA astronauts Butch Wilmore and Suni Williams closely then you'll know the challenges that they've faced with regards to their health.

Photos released last year worried people online as Williams' appeared to look dangerously thin and unhealthy, and while NASA assured everyone that she was all OK, it certainly drew attention to the strange effects that living in space can cause.

Astronauts are monitored closely by doctors and scientists following their return to Earth (Keegan Barber/NASA via Getty Images)

Your body isn't used to living in low or zero gravity environments, and thus you can very easily shed significant muscle and also suffer from bone density loss as your muscles - including your heart - don't have to work anywhere near as hard even if you do hours of exercise every single day.

Yet Williams' health concerns look fairly mundane compared to retired NASA astronaut Scott Kelly, who upon return from a staggering 340 day stay on board the ISS returned two inches taller than he was a year earlier, as reported by CNBC.

Scott's case was a particularly intriguing one when it comes to studying the effects of space travel on the human body, as he happened to have an identical twin brother who was also an astronaut.

Mark Kelly, Scott's twin, was down on Earth during the latter's lengthy ISS expedition, and measuring him up against his twin was what allowed scientists to discover the bizarre change.

Researchers also conducted a number of genetic tests between the pair of twins, as it's not exactly common to get a near perfect way to analyze the immediate differences shortly after space travel in two genetically similar test subjects.

Scott grew two inches taller than his twin brother Mark after staying in space for nearly a year (Dimitrios Kambouris/Getty Images for Breitling)

Like almost everything in space though, Scott managed to somehow grow taller due to the effects of gravity on his body. On Earth the disks in your spinal column are compressed and fixed in place, whereas the lack of gravity in space causes these to loosen, expand, and in turn lengthen your spine overall.

This is a particularly prevalent case due to the length of time that Kelly spent consecutively in the environment in space, affording a much greater expansion of his spinal column and therefore a more noticeable increase in his height.

Other bizarre side effects that are caused by the shift in gravity include a hypersensitivity that leads to 'baby-like' skin, as your clothes otherwise float above your body when you're in space, alongside a difficulty learning how to talk again as the tongue naturally floats in low gravity.