When Scott Kelly returned to Earth this week after spending almost a year on the International Space Station, he came back about two inches taller than when he left Earth.

What caused this growth? Spending time in a zero-G environment like that of the International Space Station causes the spine to stretch. On Earth, gravity keeps the vertebrae in place by constantly pushing them together. But without gravity, the vertebrae will naturally expand slightly, causing a person to become taller.

However, this growth is minor and temporary. Typically, astronauts in space can grow up to three percent of their original height, but no more than that. And after a few months back on Earth, gravity will shrink a person back to her original height.

In addition to this height increase, zero-G environments also come with a large list of other potential side effects to the human body, many of which are still pretty unknown--a reason why NASA is currently studying both Scott Kelly and his identical twin Mark, who unlike his brother spent this past year on Earth, to better understand these physiological changes.

So if you do wish you were slightly taller, consider becoming an astronaut who participates in long term space missions. But remember to relish your extended height when you're up there, because once you get back down to Earth it's all going to shrink.