NASA sent one identical twin to space for a year to see how he’d change

  • Scott Kelly and Mark Kelly are twins with identical DNA
  • Scott spent 340 days in space, while Mark remained on Earth
  • After 340 days, Scott’s body is no longer identical to Mark

Published on Nov 22, 2023 at 1:07 PM (UTC+4)
by Alessandro Renesis

Last updated on Apr 03, 2024 at 7:09 PM (UTC+4)
Edited by Alessandro Renesis

NASA sent one identical twin to space for a year to see how he’d change

We’d already learned from NASA that the human body can change, potentially even drastically, in space.

And when the US Space Agency took it one step further with a unique experiment, we also learned how.

NASA sent one twin to space for a year while the other remained on Earth, and the result of the experiment is telling.

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NASA sent astronaut Scott Kelly (pictured above, right) to space for 340 days, while his twin brother Mark Kelly (left) remained on Earth.

Scott and Mark have identical genes, the same DNA, and 340 days later, they’re a bit…less identical.

Scientists have already concluded that spending months in space can have a negative effect on the human body.

The key issue is lack of gravity, because living in a weightless environment is something the human body isn’t made for.

Our bodies are designed to be constantly affected by gravity.

That’s what keeps a lot of our ‘bits’ working, from our spine to the way our blood flows through our bodies.

In a weightless environment, our muscles may shrink, the spine may stretch and our sense of balance isn’t the same.

Among other things, NASA discovered that Scott Kelly’s chromosomes got longer, literally, but they returned to normal after he got back to Earth.

Another weird change is that Scott has different ‘gut bacteria’ now.

This is likely due to the fact that he lived on a totally different diet for a year.

The good news, for Scott, is scientists tend to agree that, in most cases and for the most part, these changes, albeit dramatic, are only temporary.

Most astronauts return to normal in a few months time.

That was the case for Scott.

He came home from space in March 2017 and by the end of the year he was already back to normal.

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Alessandro Renesis

Experienced content creator with a strong focus on cars and watches. Alessandro penned the first-ever post on the Supercar Blondie website and covers cars, watches, yachts, real estate and crypto. Former DriveTribe writer, fixed gear bike owner, obsessed with ducks for some reason.