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If we wish to colonize another world, finding a planet with a gravitational field that humans can survive and thrive under will be crucial. If its gravity is too strong our blood will be pulled down into our legs, our bones might break, and we could even be pinned helplessly to the ground.
Finding the gravitational limit of the human body is something that's better done before we land on a massive new planet. Now, in a paper published on the pre-print server arXiv, three physicists, claim that the maximum gravitational field humans could survive long-term is four-and-a-half times the gravity on Earth.
Or, at least you could if you are an Icelandic strongman – and Game of Thrones monster – who can walk with more than half a metric ton on your back. For mere mortals, the researchers say, it would need to be a little weaker.
[...] For the maximum gravity at which we could take a step, the team turned to Hafþór Júlíus Björnsson, an Icelandic strongman who once walked five steps with a 1430 pound log on his back, smashing a 1,000-year-old record[*].
[*] YouTube video.
What's the Maximum Gravity We Could Survive?
(Score: 0) by Anonymous Coward on Sunday September 23 2018, @02:39PM (2 children)
"what's the maximum gravity (acceleration) we could survive?"
reading the conclusion then the posted question means naked or unassisted.
however with a exo-skeleton we could probably do 20 G (pull-out-of-ass-number)?
the trick is probably to BUFFER the human body in the same material that it is made of, that is water.
if the container -aka- exo-skeleton is strong enough to hold water at 20 G then the human body inside will probably not feel much of the gravity.
imagine a 1G planet and the human body to be like the body of a jellyfish. the jelly-human is perfectly content being made of 99% water and floating inside the ocean. remove it from the ocean and it collapses.
now transfer the REAL human to the 20G planet and it collapses like the jellyfish ... so just add water!
ofc the exoskeleton would need a water-tight control interface (and phone charging port to be sure) and assistive motors to lift stuff "outside" the exo-skeleton.
curiously enough, there's no difference between standing on a planet with 20 G and sitting in a spaceship going 20 G or so, so if the exoskeleton works for the planet it would also work for the super-fast spaceship (or dog fighting jet?).
ofc goku, like all real men, balks at the solution and rather prefers to train until 20 G feels like 0.5 G : ]
(Score: 2) by Immerman on Sunday September 23 2018, @05:13PM (1 child)
The problem is that there's a considerable amount of density variation within the human body, and no matter how perfectly you support the outside of the body, the inside will still feel every G of acceleration. Blood and most organs are within a few percentage of water density, so they could *probably* take some serious acceleration - though then again, they're designed to operate when that similarity means there's essentially no sustained uneven stresses between cells, so who knows what the long term consequence of sustained exposure might be.
Bone though is 3x-4x denser than muscle. Your skeleton is typically about 15% of your body mass, so at 20gs of acceleration that 2-3x of "excess density" would translate to around 15%*(2.5/3.5)*20 = 2.1 times your normal weight being supported by just the tissues and organs that lay between bottom and your "bottom" outside surface at any point.
(Score: 0) by Anonymous Coward on Sunday September 23 2018, @06:47PM
well, we could simplify the human body to a simple "T" to make some conjuring easier. they do this all the time just look up radioactive exposure stuff ... so bear with me.
the two arms of the "T" are rubber ballons filled with water and attached to a steel rod.
place "T" on land and the rod supports the sagging water ballons.
place "T" in water and the ballons support the rod.
the stresses at the connection point (where the two arms) connect to center rod is not same in both cases.
if true then it says something how the stresses inside the body would look like between "very watery tissue" and less "watery" tissue, so maybe like between muscle and bone.
the main problem might just be the (closed) cavities that exist in human body. these might get compressed: one meter of water at 20 g might then feel like 20 meters at 1G? ofc theres no need to surround the body with that much water. if the exoskeleton is engineered well enough then maybe a 1 cm layer of water from all body surfaces to internal surface of exo suit would suffice?