The gravitational force on an object is equivalent to the inertial force on an object undergoing a comparable acceleration. Just as gravity pushes you down against the Earth, inertia pushes you back against your seat. We experience higher or lower g forces when we are rapidly changing speeds or directions.
Normal humans can withstand no more than 9 g 's, and even that for only a few seconds. When undergoing an acceleration of 9 g 's, your body feels nine times heavier than usual, blood rushes to the feet, and the heart can't pump hard enough to bring this heavier blood to the brain. Your vision narrows to a tunnel, then goes black.
If the acceleration doesn't decrease, you will pass out and finally die. The Air Force's F can produce more g 's than the human body can survive. We're forced to limit the acceleration of planes and spacecraft to a level humans can survive. If we need to accelerate for extended periods, the level we can withstand is even lower. We can withstand 5 g 's for only two minutes, 3 g 's for only an hour. For the sake of argument, though, let's try to tough it out at 3 g 's for a little longer.
For Han to take off from Mos Eisley and accelerate at 3 g 's to half the speed of light would take him two and a half months—hardly the makings of an exciting movie. Even at 9 g 's, it would take him nineteen days to reach half the speed of light, though he'd be dead long before the ship reached that speed. But we can hardly expect that to be entirely representative for the entire population. So what do we know? Well, gravity on earth isn't exactly the same everywhere.
None of these are wrong, but except for 9. Gravity may differ by as much as 0. This remains true when changing 'Lethal' to 'Serious effects', though there are probably obese people who would do better in lower gravity. The question is difficult impossible to answer both because no scientific data exists, and because of how it is worded. There exists some data which could be extrapolated, but it has a small sample size, was collected from a set of carefully chosen individuals, and the effect is intermixed with other effects e.
Thus, it is not possible to generalize to "nearly all humans", nor to blame any observed effect on gravity without the possibility of other factors also having an influence unlikely as it may seem, but truth is we simply don't know , we can only assume what's likely. Reduced gravity most probably predominantly leads to bone demineralization and muscle atrophy and possibly other things.
That's because this is what people who are among some other effects exposed to reduced or zero gravity demonstrably develop. There may of course be other reasons for that effect, but gravity is the likely factor.
Exercise can at least partially counter these effects, but exercise is not a premise of the question. If, what's very likely, gravity is indeed the deciding factor and not e. NASA's bad nutriention scheme simply because less "pull" means less stimulus, then the effects will likely occur at every significant reduction. Whether or not it counts as "not tolerable" is up to your decision, so it's fundamentally impossible to provide a number.
Who can tell. For a boxing champion or a rugby player it sure wouldn't be. For a computer geek? Why not. Seeing how "return to normal environment" is not a premise of the question only "compared to" is , though, one might as well say "zero gravity is perfectly sustainable" since you do not need shouldn't need?
Basically, it would mean: Yes, there will definitively be serious changes, but they aren't a problem. The same goes on the other end. Something like G will without doubt cause noticeable discomfort, and rather soon evolve into problems. However, 1G or 1. Only just, everything is a tidbit tidbit, eh?! You'll grow more muscle and denser bone, tripping and falling will hurt considerably more, and you'll need more energy.
It'll be generally harder, your heart and your circulatory system needs to support higher pressure, but all in all, there's not really that much difference. Sure, more load on your spine, your knees, and on your inguinal canal. All in all, that's not precisely enhancing durability or longeviety. But there is no real reason why you couldn't live in 2G for 5 years, if you are reasonably healthy.
Mind you, there's people who have kilograms of body weight or more?! Do they eventually have problems? Well sure, but not after 5 years. However, "nearly all" includes infants and people who are 95 years old and suffer from heart insufficiency and COPD, so A baby in zero-G will be "fun" when gooey, stinky stuff comes shooting out of it at both ends. Which tends to happen regularly. A "typical" 95 year old will not be very happy in 2G, at least not for long.
Someone with vein insufficiency will not be very happy either -- them thick legs getting twice as thick now. Allergic and going to zero-G? Well guess what, sneezing all day long can be a lot of fun! Speaking of infants, it is not certain in any way inhowfar growth in children or animals in general is influenced by low gravity.
Generally, data about animals in space is relatively sparse, and in my opinion the conclusions that are made are dangerously naive. For example it is not appropriate to extrapolate from mouse experiments based on "they have short life spans, so this is a long-time mission for them" as has been done on the ISS. 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.
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. For mere mortals, the researchers say, it would need to be a little weaker. To work out the largest gravitational force a human could function in, Nikola Poljak from the University of Zagreb in Croatia, and his colleagues first calculated the compressive strength of a human bone.
Based on an average mammal bone, they estimated that a human skeleton could support a gravitational force more than 90 times Earth gravity. But this is its strength when standing still. Once we start running, the stress on our bones — as they flex and bend — increases by a factor of ten. Poljak hopes this work will help focus our search for a habitable exoplanet.
0コメント