Gravity

DarkOmen · Post by **DarkOmen** » Wed Oct 17, 2007 3:51 pm

In reality, had she actually been from a species that lives in a low gravity environment, she wouldnt have a bone structure, or one very very different than ours.

Look at a fish... very light weight flexible bones, because they live in an environment where large bones would not help them. Even better, look at sharks... cartilage.

Post by **Captain Seafort** » Wed Oct 17, 2007 3:54 pm

Thorin wrote:I disagree - while obviously the internals wouldn't be as strong, there would be a point (for example, 0.4 of earth's gravity), where any lower wouldn't make you any weaker - because gravity is just acceleration, and you must be able to withstand acceleration at all points during your lifetime.

True, but if an organism that evolved in an environment when the typical gravitational acceleration is (for example) 0.4 g, and put it into a 1g environment, there would be problems. Humans can withstand multiple g, something like 10+ g if they've got a suit, but that doesn't mean the body likes it.

Thorin · Post by **Thorin** » Wed Oct 17, 2007 3:58 pm

Captain Seafort wrote:
Thorin wrote:I disagree - while obviously the internals wouldn't be as strong, there would be a point (for example, 0.4 of earth's gravity), where any lower wouldn't make you any weaker - because gravity is just acceleration, and you must be able to withstand acceleration at all points during your lifetime.
True, but if an organism that evolved in an environment when the typical gravitational acceleration is (for example) 0.4 g, and put it into a 1g environment, there would be problems. Humans can withstand multiple g, something like 10+ g if they've got a suit, but that doesn't mean the body likes it.

There would be problems, yes, but it wouldn't crush your internal organs.
Prolonged exposure kills you - I'm not 100% sure but I think for us, we can stand without too much trouble 3g, we can stand 5g indefinitely but feeling ill, 10g will knock you out after about 2 or 3 minutes, while 20g will kill you after 2 or 3 minutes. 100g kills you instantly. It's something like that, anyway.
I'd guess that if 0.4 was this boundry, then anything that lives on 0 - 0.4g enviroments would experience basically the same problems, whereas as this rises, people you experience less problems.

Post by **Mikey** » Wed Oct 17, 2007 4:09 pm

I think with the whole story from "The Chase" as a given, we can assume that a specific artificial genetic design overrode things like average height being a function of gravity, but the necessary adaptive traits would still be in place - such as the much greater strength vs. humans that Vulcans possess. And being in an evironment slightly (< 5 g's) off from your homeworld would probably not induce any acute effects, but one would think that chronic effects would result.

We also never talked about pressure. Let's say that Vulcan has a norm of 2 g at "sea level," and its atmosphere is substantially similar to ours. That means that at "sea level," Vulcans would be walking around experience 2 atm of pressure.. 2 atm is fine, but if you get someone from a considerably higher grav homeworld, they'd experience all sorts of respiratory, circulatory, cellular, and perhaps even hemmorhagic problems due to walking around in "our" 1 atm of pressure. Sort of like taking a fish out of the bottom of the Marianas Trench and watching it explode as you bring up to the comparatively small pressure of the surface.

Post by **Tsukiyumi** » Wed Oct 17, 2007 4:10 pm

I'm pretty sure 10g will put you out in a matter of several dozen seconds, which is why tight turns in fighters at extreme speeds are tough, and limited by the pilot's endurance.

Post by **Tsukiyumi** » Wed Oct 17, 2007 4:15 pm

Also, as Mikey said, wouldn't people from a planet with higher gravity, and higher atmospheric pressure experience effects at least similar to altitude sickness? Wouldn't people from low-gravity worlds experience something like 'the bends'? Hmmm...

Post by **Mikey** » Wed Oct 17, 2007 4:21 pm

I think you've got it reversed - we experience "the bends" when we come FROM a higher pressure TO a lower pressure. And if the gradient is steep enough, I think nitrogen bubbles would be the least of that person's problems - compared to spontaneous strokes, hemmorhaging, cellular disruption, thromboses...

Post by **Teaos** » Thu Oct 18, 2007 1:02 am

Your body can with stand quite a few G's its the organs and blood that get screwed up by high G's.

Post by **Mikey** » Thu Oct 18, 2007 1:36 am

Your body can with stand quite a few G's its the organs and blood that get screwed up by high G's.

Right - what I was referring to was tissue and systemic damage, not structural effects.

celeritas · Post by **celeritas** » Thu Oct 18, 2007 1:36 am

Mikey wrote:I think you've got it reversed - we experience "the bends" when we come FROM a higher pressure TO a lower pressure. And if the gradient is steep enough, I think nitrogen bubbles would be the least of that person's problems - compared to spontaneous strokes, hemmorhaging, cellular disruption, thromboses...

that is true and i would venture a guess that nitrogen bubbling out of the blood would cause the initial ischemic events throughout the body leading to infarcts which may then progress to disseminated intravascular coagulation that could then embolize to cause strokes at the same time the infarct causes cellular necrosis and possibly multi-organ system failure.

but in terms of increased gravity, i think the first thing i would think of is how your circulatory system would have to work to pump blood around at a higher gravity -- you're blood pressure would have to be incredible to work against higher gravity and your heart would have to be massively (and probably pathologically) enlarged. i would think that it would be very difficult to keep your circulatory system pushing enough fluid around without exploding or aortic dissection.

how to get around this problem with blood pressure: well, blue whales get pretty freaking big so they must have found out some successful way through evolution to moving massive amounts of blood through their system without explosive blood pressure. now i don't know anything about blue whales so i don't know how they do it but i would assume it would have to have something to do with the fact that they live in the water, where buoyancy might help displace some of their weight.

but at lighter gravity, i don't know if mammalian development requires any gravitational signals. it would be an interesting experiment to try to do at very low gravity.

Post by **Mikey** » Thu Oct 18, 2007 12:53 pm

Come on guys - this is a Star Trek forum after all. I'm sure someone here know of a study on acute effects of low-grac/weightless environments.

Post by **Teaos** » Thu Oct 18, 2007 2:18 pm

No doubt Thorin will show up with some weird science then act all superior wondering how anyone cant know it already.

Post by **Mikey** » Thu Oct 18, 2007 2:21 pm

ROFL! Bullseye, Teaos!

DarkOmen · Post by **DarkOmen** » Thu Oct 18, 2007 3:52 pm

some of the problems we face concerning gravity....

http://www.space.com/businesstechnology ... 00407.html

Post by **Mikey** » Thu Oct 18, 2007 4:57 pm

I'm willing to believe that there is some technobabble in 'Trek that can avoid these types of effects on equipment - my concern is still that folks from a (relatively) low-grav world would suffer from increased wieght on their structrues and increased atmospheric pressure, while people from a high-grav world would tend to suffer from the relatively low pressure - in the most extreme examples, popping like overfull balloons.