Surface Gravity

Garuda

Mongoose
I ask these questions because I really have am clueless when it comes to science.


How might a human being be affected by living on a world with a lower surface gravity than Earth. Lets sat 0.5g ?

What effects on health? Would a person be light headed or suffer nausea? Can a person become acclimatised? In the Traveller Universe would there be any medication or implants to overcome adverse effects? Would a person be able to walk normally?


What if the surface gravity were greater than Earth? Say 1.5g?

What effects now? Would a person's joints (especially hips and knees) be under stress (requiring joint replacements at a failry early age)? Would wearing clothes made of normal textiles feel heavy? Would walking long distances require lots of stamina? Would a person be required to excercise more in order to keep fit? Would vehicle design be very different from those used on world's with lighter surface gravity? Would the difference between 1g and 1.5g actually be quite negligable?


Anything that can be contributed, especially in regard to the effects of light surface gravity, would be appreciated.
 
Being a little 'science literate' but no expert, I can offer you a little bit.

at 0.5g you are probably looking at loss of bone density over time. I know this is a problem for long term stays at like, the International Space Station, but I don't have any hard evidence on like what kind of loss might be expected for a certain length of stay.

EDG is really knowledgable in the space/planetary area and if the thread catches his eye he could probably give you an answer that will be more than satisfactory. (meant sincerly).
 
For the light gravity case, you might want to look at the "vomit comet", a plane used for testing astronauts for the microgravity environment in orbit. Also take a look at the astronauts on the moon (though there only for a few days).

In general, people should be able to adapt without much trouble. The zero-g throws some people because it screws up their sense of balance. But even the Moon's gravity (0.16G) is sufficient for normal operations.

There may be some long term health effects we're not aware of. In orbit, the calcium in the bones begins to get lost and the muscles atrophy from disuse. This is combated by a combination of specific exercises and a centrifuge for people.

Similar with the Higher G ratings. I've seen people claim that humans could adapt to as high as 2G without too much difficulty. Again there may be some long-term medical effects we're not currently aware of.

You could simulate a lot of the high gravity effects on yourself simply by adding a large amount of weight to a pocketed vest and pants. Like half your body weight. It's difficult and tiring to move around, but there won't be any immediate damage.
 
tjoneslo said:
For the light gravity case, you might want to look at the "vomit comet", a plane used for testing astronauts for the microgravity environment in orbit. Also take a look at the astronauts on the moon (though there only for a few days).

That gravity is much lighter than 0.5g though. Even lunar gravity was hard to move around in (hence the "bunnyhop" that they figured out on the later apollo missions - that was easier than walking, apparently).

TBH I don't think there's been much research done on how the body adapts in the longterm to gravities in the range of 0.5 to 1.5g - it's all been microgravity, lunar gravity and zero g.

You could simulate a lot of the high gravity effects on yourself simply by adding a large amount of weight to a pocketed vest and pants. Like half your body weight. It's difficult and tiring to move around, but there won't be any immediate damage.

Here's one thing - in a 2G environment you'd hit the ground much harder if you tripped over something, or jumped off a wall. Whether or not our bones could adapt to that sort of higher stress all around (at least without artificial help) is unknown. I think there'd be a lot more wear and tear on joints.
 
Actually this turns into an interesting Demographics question.

What is the average home G rating of the Imperium?

It has to be something lower than 1g, being that the average inhabited world is a size 5 which is about 0.5g.

Now think about the implications of that.
 
Infojunky said:
Actually this turns into an interesting Demographics question.

What is the average home G rating of the Imperium?

It has to be something lower than 1g, being that the average inhabited world is a size 5 which is about 0.5g.

Now think about the implications of that.

Curveball time: Is that the average with all worlds weighted equally? Or is it weighted by population?
 
FreeTrav said:
Infojunky said:
Actually this turns into an interesting Demographics question.

What is the average home G rating of the Imperium?

It has to be something lower than 1g, being that the average inhabited world is a size 5 which is about 0.5g.

Now think about the implications of that.

Curveball time: Is that the average with all worlds weighted equally? Or is it weighted by population?

Haven't sat down with excel yet.

But just playing with mentally it tends to trend towards the center. In that both rolls in System generation are flat.

With a full array of possible population (1296 per) results possible size results indicated that.
 
Garuda, NASA's site on the subject may have some useful info. I don't think it cover hi-G worlds though.

http://science.nasa.gov/headlines/y2001/ast02aug_1.htm
 
Well,

Reading little snippets on various sites - if somebody were a native fully adapted to a surface gravity of 0.5g the concensus seems to be that as doing tasks in lighter gravity is less strenuous a person would likely have
less muscle density and be more prone to having brittle bones than we are. And they would likely be quite tall and slender with less stongly developed hearts and lungs.

A general problem proposed for low gravity worlds seems to be that it would bleed heavy gasses such as oxygen (including oxygen locked in water) and after a few hundred million years oxygen and water would become absent. For humans this would mean a requirement to regulate the atmosphere by artificial means.

This of course may all just be theory.
 
Infojunky said:
FreeTrav said:
Infojunky said:
Actually this turns into an interesting Demographics question.

What is the average home G rating of the Imperium?

It has to be something lower than 1g, being that the average inhabited world is a size 5 which is about 0.5g.

Now think about the implications of that.

Curveball time: Is that the average with all worlds weighted equally? Or is it weighted by population?

Haven't sat down with excel yet.

But just playing with mentally it tends to trend towards the center. In that both rolls in System generation are flat.

With a full array of possible population (1296 per) results possible size results indicated that.

Under the standard system, population is independent of world size (or anything else).

So, you will have two independent curves. So there shouldn't be any variation based on population. The average size world is Size 5 (2D-2), wihich is 0.5g (ish). Population shouldn't skew that.

If you are using the Space Opera or Hard Science Rules, then there will be a skew towards larger worlds (needed for the breathable atmospheres). I'm not good enough with statistics to figure out how much it would move it up, but figure Size 6-7 is probably closer to the population-weighted averge in these situations.
 
Rikki Tikki Traveller said:
Under the standard system, population is independent of world size (or anything else).

Yep, was over complicating my set up.....

The percentages in the theoretical population bear out the the odds of the dice throw, in that the majority of the population lives on worlds with a gravity range of 0.35 to 0.7g.

Now another point ponder, what is the average gravity of size 0 (and size 1 for that matter) systems? Considering the prevalence of gravity technology.
 
That is the sixty-four thousand credit question.

How prevalent is large-scale gravitic manipulation?

If ships can be fitted with AG at no additional cost except hull costs, then what is to stop an entire asteroid (size 0) or Moonbase being fitted with Grav plates.

A 1 MTon ship is about the size of a decent base for 10,000 people, so if one can have AG, why not the other?

I figure by TL12, gravity manipulation is ubiquitous and so common people don't even notice it anymore. Parks have circular rivers with part of the way being upstream (yes I stole that from Arthur C Clarke, but it s a valid point). If you can have flying cities, you can have gravity control on cities.

By TL 12, any world that has low gravity effects (bone density changes etc) would have AG to compensate and everyone would live at 1g. Same for High Gravity worlds, every city would have AG plates and no one would even think twice about it.

Past TL12, the Zero-G skill becomes much less valuable or usable, since everything has gravitic control.
 
Rikki Tikki Traveller said:
That is the sixty-four thousand credit question.

How prevalent is large-scale gravitic manipulation?

That is the question.... (snip a bunch of description)

I tend to run games where the universe has a homologous spread of technology. With various flavors of Gravity Tech being one of the cornerstones technic civilization.
 
Rikki Tikki Traveller said:
Past TL12, the Zero-G skill becomes much less valuable or usable, since everything has gravitic control.

Does that include the asteroid you land on to retrieve something? The lost ship floating in space with non functioning systems? While you are clinging to the outside of the hull in a spacesuit hiding from the authorities that are searching the ship?

Not to mention those planets at a lower tech level you may visit.

Just saying I would say everything has gravitic control. And the skill can still be rather useful.
 
I'm just re-reading a book about the Apollo missions, and as far as psychology goes, Lunar gravity is no problem for a human to adapt to. I'm sure, in the longer term, there would be a loss of strength and bone density (mitigated by regular gym sessions no doubt).

It's fair to say though, that the Apollo astronauts absolutely revelled in Lunar gravity ! They found it no problem at all to adapt to: having any sense of up and down was a godsend after days in zero-g, and yet the lightness of the gravity made physical tasks much easier. Loads that were heavy on Earth could be slung over the shoulder; John Young jumped about 3 feet straight up in the air for a photograph (even in a spacesuit); sleeping was a joy, as body weight was so low that they barely pressed into their hammocks.

The hardest things to adapt to were the pressure suits - flexing the joints, especially the gloves, was hard work, and this was what tired the astronauts the most. They also had to re-learn the best way to walk, arguably also due to the spacesuits, leaning way further forward than felt 'right'.

Something that bears mentioning is that although weight changes with gravity, inertia doesn't. So a heavy object becomes lighter on the moon, but it still takes the same energy to get it moving, and to stop it again. This can catch you off guard: eg wearing a heavy backpack which feels light on the moon, but when you try to stop walking it's inertia feels greater than it 'should' for it's weight, and you have trouble stopping.

Another thing - ground pressure is less. This is important for vehicles: tires will barely sink into the surface, even when loaded. Parking on an incline can be dangerous, as the vehicle will tend to just slide down the hill like a piece of styrofoam !
 
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