'The Mountain' from 'Game of Thrones' Is Being Used to Test How Much Gravity Humans Can Withstand

Tuesday, 02 October 2018 - 11:40AM
Physics
Space
Tuesday, 02 October 2018 - 11:40AM
'The Mountain' from 'Game of Thrones' Is Being Used to Test How Much Gravity Humans Can Withstand
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Image Credit: Paula R. Lively/Flickr CC BY 2.0
In Westeros, Ser Gregor "The Mountain" Clegane is famous for being stupidly strong, but we didn't expect the real-life actor, Hafþór Júlíus Björnsson, to live up to his character's larger-than-life reputation. In a case of life imitating art, Björnsson recently broke a millennia-old world record by carrying a 1,430-pound weight for five steps (for scale, that's equivalent to lifting about 7 large washing machines). Apart from proving that Björnsson could be the real-life Mountain, his feat of strength has actually given scientists an upper limit to what humans may be able to withstand when it comes to trekking across high-gravity exoplanets.

Stress-testing the human body is an interesting thing: according to Mike McRae from Science Alert, a human tibia bone alone can withstand 90 g by itself, but viewed as a whole unit, our skeleton can only withstand about 10 g before things start to go horribly wrong. That threshold is lowered even further when you know that our muscles can only deal with about 5 g of force pushing down on us, and (coincidentally) 5 g is just about the limit for our heart to function—any more, and we'd start blacking out.

So what about Björnsson?

Björnsson's record-breaking five steps give scientists a model for how well the human body's gait can withstand high gravity on a super-sized exoplanet, essentially telling them where our ability to walk would start to fail. Based on their calculations, a Mountain-sized astronaut with similar training to Björnsson could barely manage to walk in 4.6 g. Considering the limits of the human heart, that looks like the max amount of gravity anyone can handle and still put one foot in front of the other.

As for the rest of us, it's estimated that 3-4 g would be doable, which means there are a lot of exoplanets we could potentially explore. The largest rocky exoplanet discovered so far, dubbed BD+20594b, would exert about 3 g at its surface. It wouldn't be a cake walk, but it's certainly something astronauts could handle , especially if they have something like a robotic exoskeleton to help them with walking around.

Meanwhile, if aliens from a high-gravity planet ever challenge humans to a duel for the honor of our species, it looks like Björnsson is going to be our champion.

Cover image credit: Paula R. Lively/Flickr CC BY 2.0
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