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PostPosted: Tue Jul 26, 2011 1:36 am 
Smeric
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So my conworld has less gravity than earth: I'm not sure, but I figure like 0.5 to 0.6 G and a moderately thicker atmosphere. This means that everything weights less. it means that inertia and drag are comparatively more important than weight. It also means that flying animals can be much larger, and that, for instance, cavalry tactics are much different, since a horse can carry effectively twice the weight and still be able to charge. I imagine trees would be able to grow taller, since circulation is made easier by lower gravity. Most locomotion methods are much easier, so animals can be bigger without needing

However, gravity is such a base parameter in our world that I can't possibly imagine every consequence a lower gravity might have, especially regarding animals: would animals be taller? less muscular since they don't need to deal with lifting their own weight? somewhere I read that lower gees might produce more slender things, but I dunno, being bigger and having longer limbs creates the problem of flexion and inertia: even without gravity, a heavy thing has momentum, and the longer and less muscular the limbs, the less able it is to take force.

Jumping becomes a much better way of locomotion, but how better? Here's when not paying attention to physics in school, mainly cinematics, is definitely taking its toll... this whole thing is unintuitive to me: If I weighted half what I weight [cause gravity is halved], how far would I be able to jump? twice as high? would I be able to, say, run faster? how do less weight but same inertia conjugate, is what I wonder.

Okay, lemme wrap this up: I know this has been a messy exposition, but the problem might be interesting to some of you. There's two questions here, it seems.

- how would 0.5G affect zoology, as in how would earth animals adapt to lower gravity?
- how would 0.5G affect human biomechanics? as in jumping, running, and stuff.

I guess the underlying question is about low gravity and locomotion. what's up with that? any ideas?

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PostPosted: Sun Aug 28, 2011 9:21 am 
Avisaru
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If I understand things correctly, the animals' height would be inversely proportional to the gravity, and there is no particular reason why they should have a different shape. In other words, if you have half the gravity, an elephant might be twice as tall, but have the same shape, and therefore eight times the weight.
But there are some other concerns. If the elephant was bigger, it would have less heat dissipation, which might potentially be bad for it.

By the way, it's usually a lowercase g. Uppercase G is a different constant. And it might be more correct to say that you have a different g. That is, instead of "0.5 G" you might want to say "g = 5 N" (since g on earth is about 10 N).

As for flying, remember that the air would also be less affected by gravity, so you would get less lift force. With the same atmosphere density, I don't think you would get bigger flying animals. Higher density should help, tho.

Unfortunately a lower gravity would not be as good at keeping an atmosphere, so if you want the same or higher density, I think you would need different gases. That might have a much bigger impact on biology. Then again you might be able to make it so it doesn't; maybe replace nitrogen with krypton or argon? That would lead to two other interesting consequences: First, everyone would get a much lower voice. Second, barbecue would not be bad for you.

Jumping, on the other hand, should be easier. Since the energy at the top of the jump is m*g*h, half the gravity should lead to twice the height. The velocity at takeoff and landing would would be four times as big, and the momentum twice as big - maybe that would increase the risk of injury? Not sure about that.

I would think that a human should be able to run a little faster, but too little gravity is not good. Look at formula 1 cars - they have fins to basically increase their gravity.

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PostPosted: Wed Oct 12, 2011 7:31 pm 
Sanci
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I dabble in physics. Don't give my words too much weight. To the best of my knowledge...

Effects of 0.5g on Earth Zoology

Size
Gravity has little bearing on the allowable sizes of animals. Earth has always had the same gravity, yet in the past, there were foot-long centipedes, dragonflies with three-foot wingspans and large dinosaurs. Why did such large creatures decline? Oxygen and temperature.

The bigger you are, the more oxygen you need. Whales today can become very large because water-based respiration is efficient. Air-based respiration is comparably inefficient. In the distant past, atmospheric oxygen levels were much higher. This allowed air-breathing terrestrial animals to grow large. Today, with little atmospheric oxygen, organisms on Earth are limited to the sizes they are. A dinosaur reborn today would suffocate within minutes.

Dinosaurs in particular, being cold-blooded, were also able to grow large because of warm global temperatures. Warm-blooded creatures never got as large as dinosaurs because they would overheat. Whales are an exception because the oceans are relatively cold.

An 0.5g environment wouldn't necessarily engender larger creatures.

Bone Structure
Astronauts rapidly lose bone density in zero g. It seems the constant struggle against gravity on Earth helps keep bones strong. An Earth creature that has bones would suffer similar effects in a 0.5g environment. Bones would become brittle and prone to breakage. Something as large as an elephant would likely go extinct, its skeleton becoming too fragile for long-term viability. Giraffes, too. Alternatively, such species might shrink.

Plants
Plants which send roots into the ground use gravity as a cue, to sense direction. Plants have a difficult time growing on space stations because they don't "know" which way to grow. Roots and stems are sent equiprobably in all directions, resulting in inferior specimens.

In a 0.5g environment, the effect would be less. Likely, plants with deep roots (large trees, desert plants) would go extinct, due to inability to properly root themselves. Alternatively, they might shrink. Plants with shallow roots, especially those that spread horizontally, wouldn't be affected. This includes almost all food crops.

Plants which rely on wind to carry their seeds would have an advantage in a lower-gravity environment; their seeds would carry farther. Over time, the percentage of plants worldwide which pollinate across the air would increase.

Growth
As stated above, a 0.5g environment would likely engender smaller plants and animals, not larger. However, due to reduced gravitational stress allowing more energy to be devoted elsewhere, most species would likely have sped-up growth cycles. Gestation periods would be shorter, maturation would occur sooner. Lifespans may increase or remain the same.

Rats, rabbits and other fast-reproducers would experience acute population surges. The effects of such are complex and multi-faceted, but likely destructive in the short-term. Greenery would overrun areas more quickly.

Locomotion
Earth's moon has 1/6 the gravity of Earth. Astronauts who've walked on its surface report great difficulty in simply moving around. Walking on the moon is essentially impossible; one must hop. Think of the iconic Apollo 11 footage.

Though 0.5g is less extreme, similar effects would be observed. Walking and running would be more difficult than normal. Hopping would become the predominant form of locomotion. Four-legged predators would change shape significantly. Likely to forms more closely resembling their four-legged prey, who already tend to hop. Kangaroo-like feet would be unnecessary in size, but not shape. Since the force of gravity would be less, such large feet would be unnecessary, but the shape would be apt.

Large mammals like elephants, hippos and rhinos, which tend to slowly amble, wouldn't be able to move properly in 0.5g. Lighter, slimmer, more fast-paced animals would dominate.

Small, fast-movers such as rabbits might evolve gliding wings to further extend the length and maneuverability of their hops. Likely, these wings would evolve from existing structures. For example, squirrels might develop membranous flaps inbetween their limbs, or rabbits ears might become strong, flat, fan-like and prehensile.

Flight
Wind resistance is more important to flight than gravity. The engines of flying vehicles would need to be redesigned to calculate the new 0.5g level, but the end product would be essentially the same. Fuel efficiency would improve, because aircraft would naturally be lighter.

With gravity reduced by half, flying birds would tend more towards gliding and less towards flapping. The hummingbird would probably not exist in a 0.5g environment. Since gliding requires less energy than flapping, larger wingspans and in turn larger birds would emerge. Smaller birds wouldn't go extinct in and of themselves, but larger birds would tend to prey on them, making global average bird size increase.

Insects
Gravity has little effect on insects. If you threw an ant off the Eiffel Tower, it would sustain no damage; its miniscule weight would be canceled out by wind resistance. However, insects which tend to crawl on inverted surfaces would have an easier time in 0.5g. They'd move faster. They may lose legs over generations, as they wouldn't be as necessary.

Sea Life
None of the above applies to marine species. Gravity has little effect underwater.

Humans
Bone density loss and difficulty moving due to reduced gravity would likely change the modern tall, lanky human shape to a more primitive short, stocky shape. Today, worldwide average adult human height ranges from 160 to 180 centimeters based on race. That would likely drop by at least 30 and possibly 50 or more centimeters. Arms, legs and torsos would get shorter and thicker. Bones would get larger and thicker. In both cases, this would act to combat reduced bone density from reduced gravity.

Movement would tend away from walking and towards hopping. Speed would lower, too. Again, picture astronauts on the moon.

Though you'd run slower, you could probably run for a much longer period of time. Lower gravity, less resistance and greater hangtime would slow you down, but also require much less exertion. A healthy adult might run for twenty miles straight without experiencing fatigue.

Effects of 0.5g on Ballistics
Though you didn't ask, ballistic effects rely almost entirely on gravity. In half gravity, bullets, RPGs and missiles would travel twice as far. This would have profound effects on battlefield tactics.

Effects of 0.5g on Sports
Because ballistics and human movement would change, most sports would change. Golf would be played on larger fields, since balls would travel farther. Association football and American football would have doubly large playing fields and modified rules to incorporate the hopping movement and smaller, stockier stature of 0.5g humans. Basketball and volleyball nets would be twice as high. Tennis courts would be wider, though the nets would become shorter proportionally to human height loss. Aquatic sports wouldn't be affected much, save for water volleyball and similar.


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PostPosted: Wed Oct 12, 2011 8:03 pm 
Avisaru
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And some notes, with other notes including the increase in air pressure as well as the reduced gravity.

Observer wrote:
Bone Structure
Astronauts rapidly lose bone density in zero g. It seems the constant struggle against gravity on Earth helps keep bones strong. An Earth creature that has bones would suffer similar effects in a 0.5g environment. Bones would become brittle and prone to breakage. Something as large as an elephant would likely go extinct, its skeleton becoming too fragile for long-term viability. Giraffes, too. Alternatively, such species might shrink.

In zero gs, yes. But why would this happen in .5g? Bones would weaken somewhat, but probably not tremendously, due to there still being some gravity. The bone weakness would probably be offset by the animals lighter weight. Running into something at speed could be more dangerous due to weaker bones though... inertia would remain constant, ignoring any mass loss.

Quote:
Plants
Plants which send roots into the ground use gravity as a cue, to sense direction. Plants have a difficult time growing on space stations because they don't "know" which way to grow. Roots and stems are sent equiprobably in all directions, resulting in inferior specimens.

In a 0.5g environment, the effect would be less. Likely, plants with deep roots (large trees, desert plants) would go extinct, due to inability to properly root themselves. Alternatively, they might shrink. Plants with shallow roots, especially those that spread horizontally, wouldn't be affected. This includes almost all food crops.

I think that the plants would adapt, and .5 g probably is enough that it won't cause too many problems for roots to find down...

Quote:
Plants which rely on wind to carry their seeds would have an advantage in a lower-gravity environment; their seeds would carry farther. Over time, the percentage of plants worldwide which pollinate across the air would increase.

Especially if the air is denser as well.

Quote:
Flight
Wind resistance is more important to flight than gravity. The engines of flying vehicles would need to be redesigned to calculate the new 0.5g level, but the end product would be essentially the same. Fuel efficiency would improve, because aircraft would naturally be lighter.

The increase in air pressure could cause problems, but wings could be smaller due to both lighter weight and increased air pressure, reducing drag. Maneuvering would be harder though due to reduced wing size and a lack of reduced inertial.

Quote:
Humans
Bone density loss and difficulty moving due to reduced gravity would likely change the modern tall, lanky human shape to a more primitive short, stocky shape. Today, worldwide average adult human height ranges from 160 to 180 centimeters based on race. That would likely drop by at least 30 and possibly 50 or more centimeters. Arms, legs and torsos would get shorter and thicker. Bones would get larger and thicker. In both cases, this would act to combat reduced bone density from reduced gravity.

No need for shrinking, and even if we did shrink, there wouldn't be any need to become even more stocky. Due to reduced gravity, there wouldn't be anything pushing the bones to become thicker.

Quote:
Effects of 0.5g on Ballistics
Though you didn't ask, ballistic effects rely almost entirely on gravity. In half gravity, bullets, RPGs and missiles would travel twice as far. This would have profound effects on battlefield tactics.

Truly ballistic flight would go twice as far, ignoring air friction... powered flight (RPGs, missiles) would be harder to examine.

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PostPosted: Thu Oct 13, 2011 1:27 am 
Avisaru
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And on a simpler note, whales do not breath water as they are mammals, not fish or amphibians.

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PostPosted: Thu Oct 13, 2011 6:59 am 
Sanci
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Lyhoko Leaci, I imagined humans becoming stockier to combat bone breakage due to reduced density. Someone would be more likely to break bones during a fall if they were long-limbed, compared to if they were short-limbed.

vampyre_smiles, you're right. I zoned out during that large post. Water respiration is more efficient than air respiration, but whales are not an example.


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PostPosted: Thu Oct 13, 2011 9:17 am 
Avisaru
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Observer wrote:
Lyhoko Leaci, I imagined humans becoming stockier to combat bone breakage due to reduced density. Someone would be more likely to break bones during a fall if they were long-limbed, compared to if they were short-limbed.


But lower gravity reduces the force of a fall. Unless falling for long distances has somehow become much more common, I don't see why you would get stockier.

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PostPosted: Thu Oct 13, 2011 10:48 am 
Lebom
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Ah, the "Final Fantasy" world. I did one of these at one point, too. Airships, dragons, and crazy acrobatic combat... fun!

I would dismiss some of the issues brought up before about retaining an atmosphere. If the atmosphere is thicker than Earth's, you can have the orbit be a little further out relative to Earths, adjusted for the luminosity of the star. The increased greenhouse effect could make up for the difference. A cooler star would produce less UV, which would strip less water from the planet over time. If you want more CO2, less landmass helps - your world could be a bit watery. There are issues with tectonics slowing down over time, but Earth spent a whole lot of time in a snowball phase; you could have a planet with intelligent life in 2 billion years instead of 5 if it started out a touch warmer. For comparison, Mars had active volcanoes for 1.5 billion years, and this planet would be several times the size of Mars.

To the questions:

Regarding physiology: Gravity is less, but inertia is the same. Small animals will be able to jump significantly higher. Large animals have to worry about forward momentum snapping their legs when they land. Overall I think you have larger animals that can jump (or use jumping as a primary mode of locomotion) than you have on Earth, but jumping would be by no means the primary mode of locomotion.

With a thicker atmosphere (I'm assuming a higher concentration of oxygen than earth) you can have larger animals with higher metabolisms. The reason humans lose bone density in zero-g is because we didn't evolve for it. Animals on this planet will have no problem with low-g because they are adapted for it. I expect to see some taller, more slender creatures, but also some bigger, stronger, more bulky creatures. A lot will have to do with environment - what works best for predators and prey, foragers and grazers, etc. Being big has been a successful strategy on Earth, so I predict at least some megafauna.

I think the biggest winner in a low-g, thick-atmosphere scenario is flight. Consider: if you have 2 atm and only 0.5g, the effective lift of a wing is increased by 4x relative to the weight. A human could fly under his own power with a set of artificial wings. The largest flying animals could easily weigh hundreds of kg and have wingspans of over 20m (just extrapolating from pterosaurs and modern birds, with the respective atmospheres they had to work with). That's not quite dragon-sized - more like a flying grizzly bear - but it's damn scary if you happen to be on the ground when one of these things is on the hunt. And it's almost certain that humans will discover flight way before they did on Earth (note: lighter-than-air is easier on this planet, but only by 2x instead of 4x; I still think people figure it out before heavier-than-air).

Combat. Well, the first thing is you'd be able to wear some ridiculous armor. Weight is a serious issue with armor, and while it would still slow you down (that whole inertia thing) it wouldn't weigh you down. You could certainly run, jump, and be more maneuverable in "normal" or light armor, too. Swinging a weapon wouldn't be any faster, but you could carry a heavier one - and you'd probably have to, if your opponent is wearing 100kg steel plate. That would certainly create an interesting dynamic between quick, athletic combatants, able to jump well over an opponent's head (a 3m high jump wouldn't be unreasonable at all for a trained athlete in 0.5g) designed to strike at the weak points of their opponents, and big, slow, lumbering tanks with massive weapons and equally massive armor.

Cavalry would be interesting. You could probably have flying mounts, assuming a species that's reasonably trainable and can carry the extra weight exists in your world. But cavalry combat would be largely the same, maybe with a bit bigger mounts than Earth horses. At some point, the animal is the weak point of a cavalry unit rather than the rider; it's much harder to armor a one-ton mount than it is a 75kg human. Large mounts would require larger weapons, which I think would be unwieldy on whatever-back. So maybe cavalry doesn't change much at all, except for the odd flying unit.


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PostPosted: Thu Oct 13, 2011 2:14 pm 
Lebom
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Three other things:

1. Balance is easier in low-g; you literally fall more slowly (75% as fast in half gravity). Interestingly, this actually helps both larger bipeds and smaller ones. Kids fall down so easily because they fall to the ground faster than adults relative to their height. On the other hand, you can support twice the mass on two legs in half gravity. So more bipeds all around, and the possibility for some smaller humanoid bipeds than are feasible on Earth.

2. Knees and ankles. The trick isn't running fast - it's stopping. Remember that while weight is increased, inertia is not. Expect knee injuries when people carrying significant weight hit the ground laterally at speed. Heavy armor probably requires offensive-lineman-style knee and ankle braces, to prevent torn ligaments if you get knocked around.

3. Pole-vaulting. Sure, somebody in pretty good shape can jump 3m in the air. But with a nice springy pole? How about 8m - 10m for top athletes! You'd better build your walls high, or the enemy's light troops are going to come flying right over.


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PostPosted: Thu Oct 13, 2011 5:19 pm 
Sanci
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I think this is my first post here on zbb, please be gentle!

Something that you should be aware of is that physics play a very important role for how organisms are built. Gravity is a force that affects pretty much all living things, with the possible exception of very small ones. Obviously a change in gravity as large as this one would mean largely different animal physiology.

The first thing that comes to mind is bone structure. There's a reason why animals don't get bigger than they do, and as far as I know it has little to nothing to do with oxygen. There are crocodiles that can weight over a (metric) ton, and they have very inefficient lungs compared to ours. While I'm on the subject I'd like to point out that whales are mammals and breath air just like we do, their size is justified by other means, as I will explain shortly. If you look at the bone structures of animals of different sizes you will find that the bigger an animal gets, the thicker its bones are. Sounds pretty obvious, but there's more to it. If an animal doubles in say height while retaining its proportions, its volume, and consequentially also its weight, is cubed. Height is measured in m while volume is measured in m³, so that should be easy to see. This means that if an animal doubles in height, the bones in its legs will have to be eight times thicker to bear the new weight of the animal. There comes a point when the bones can't get thicker, simply because eventually the legs will get too thick to fit under the animal. Here's an image for better clarity. I kept the text below for those of you who read Swedish. http://i55.tinypic.com/1xz4lh.png

By now you should be able to figure out why the biggest creature currently known and living is waterborne and not legborne. I honestly have no idea how dinosaurs could get so frickin' big, but somehow they managed to get around this problem. I'm not even going to speculate, I'll let the paleontologists or whoever is interested do that.

So, in lower gravity we could expect possibly larger animals with more slender legs relative to their mass/size/height/volume.


As has already been mentioned, walking in lower gravity will be slower. This is because the walking motion we and other mammals use uses centrifugal force in the gravity plane (I have an exam in linear algebra next week so my head is full of matrices, vectors and planes, sorry if this confuses you!), which means less force needs to be applied for the foot to loose conact with the ground. Consequently, you will start running earlier, and the highest possible walking speed will be lower. Theoretically, very much so, maximum velocity is less or equal to sqrt(leg length * gravity) which apparently (this is how it was presented to me, I have not done any calculations) is around 3m/s for an average human male on Earth. Using the same formula with your gravity, it would be around 2.3m/s or so. The actual walking speed is of course lower, most people probably won't be able to walk much faster than 2m/s. 1.3m/s is the average human walking speed according to Wikipedia. Longer legs should increase walking speed.


To summarize: animal proportions will be very different. One more examples, just for fun! Animals could have bigger heads. Earth animals have several different solutions for holding their heads upp. Elephants have huge paranasal sinuses and very thin craniums to reduce the weight of their head, and elks have flexible tendons going from their skull to their backs to be able to hold those antlers upp high. They actually have to use force to lower their heads, if I remember correctly!


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PostPosted: Thu Oct 13, 2011 11:25 pm 
Lebom
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Regarding speed:

The limiting land speed factor for animals is probably metabolic, so your cheetah analogue could be even faster. And your big bruiser predator or bull/ox/rhino might also have a higher top speed. But probably not all that much higher - again, the big problem is stopping since you still have the same inertia you do on Earth and you don't want to snap your legs off or tear up your joints. There will be evolutionary pressure for both predators and prey in savannah-type settings to move quicker, at least in short bursts, so expect at least some animals to be faster than those typically found in the same environments on Earth. But because of the inertia issue, I would not expect running animals to have much more spindly/slender legs than their Earth counterparts. Feet may be bigger to get more purchase, as friction is proportional to gravity and therefore each foot wouldn't have as much grip on the ground, all things being equal.

Now, considering humans specifically - and with Earth-type proportions:

We've invented shoes, so friction is not as much of an issue as it could be - just wear cleats if you're on loose ground. Stride length is important for speed, but so is the ability to push off the ground as often and as powerfully as possible (at least for sprinting). So it might take you a bit longer to get up to speed, what with all the bouncing. But then again, I think you'd get used to it after a bit and learn to push off more horizontally (perhaps by leaning forward a bit?) so maybe it's a wash? Zwap might be right that the sprint speed for humans, specifically, assuming they're not physiologically adapted to the planet, might be slower than on Earth.

Maybe even for all animals, if the lower friction and longer stride length more than balances the higher potential energy output?

Or maybe straight-line top speed is higher, but you can't cut as easily?

I don't know. There are a lot of factors here.


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PostPosted: Fri Oct 14, 2011 4:10 am 
Sanci
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spats wrote:
Regarding speed:

The limiting land speed factor for animals is probably metabolic, so your cheetah analogue could be even faster. And your big bruiser predator or bull/ox/rhino might also have a higher top speed. But probably not all that much higher - again, the big problem is stopping since you still have the same inertia you do on Earth and you don't want to snap your legs off or tear up your joints. There will be evolutionary pressure for both predators and prey in savannah-type settings to move quicker, at least in short bursts, so expect at least some animals to be faster than those typically found in the same environments on Earth. But because of the inertia issue, I would not expect running animals to have much more spindly/slender legs than their Earth counterparts. Feet may be bigger to get more purchase, as friction is proportional to gravity and therefore each foot wouldn't have as much grip on the ground, all things being equal.

As complex as nature is we can almost assume that there are many factors determining our max speed. It's not just a question of how fast you can run, you also have to maintain that speed if you actually want to get anywhere. Generally, from my knowledge anyways, animals with more slender legs can run fast for a very long time, while those with thick legs can run very fast for a very short period of time. A good example is an antelope versus a lion. The large muscles in the lions legs are great for spurting to catch an surprised prey, but drain too much energy to allow the hunt to continue should the prey get away. I believe this, too, is because of inertia. The way the animals are built, possibly the strongest force (I don't know, but I know it's an important factor and the reason for all this) the leg muscles have to deal with is the inertia present when the leg is moved forward after a dash. The heavier the leg, the harder it gets to run. Fast runners, typically prey, loose as much weight as possible from their legs. Bones merge and feet turn into hooves. Imagine an antelope with big bulky feet, the weight and inertia would probably prevent it from running at all. Unfortunately, this makes any movement that's not moving forward inefficient and clumsy. Look at a horse turning on the spot, compared to a tiger doing the same.
Lower gravity means less need for thick legs. Thinner legs means more running time. So, there will probably be some pretty good runners on your planet. Of course they will have a hard time stopping, as has already been pointed out, so evolution would have to deal with that somehow. Perhaps your world would just be full of centipedes. To be honest I have a hard time justifying analogically evolved humans on a planet such as yours, I think they would be too different to call humans.

Edit: To clarify, convergent evolution, when unrelated species have very similar physiology, happens every now and then, but only because those species live under the same conditions and take the form that's most suitable in their environments. 50% gravity is not under the same conditions. Then again Random, the mighty god of chance, can have a very strong will some times, especially in conworlds.

Quote:
Now, considering humans specifically - and with Earth-type proportions:

We've invented shoes, so friction is not as much of an issue as it could be - just wear cleats if you're on loose ground. Stride length is important for speed, but so is the ability to push off the ground as often and as powerfully as possible (at least for sprinting). So it might take you a bit longer to get up to speed, what with all the bouncing. But then again, I think you'd get used to it after a bit and learn to push off more horizontally (perhaps by leaning forward a bit?) so maybe it's a wash? Zwap might be right that the sprint speed for humans, specifically, assuming they're not physiologically adapted to the planet, might be slower than on Earth.

I'd like to argue that if the humans are in fact physiologically adapted to the planet they aren't really human anymore. Unless they arrived there from Earth many generations ago and slowly changed, but then they would have a very hard time competing with whatever creatures already live on the planet.

Quote:
I don't know. There are a lot of factors here.

I agree. There's really no way for us to know what life on a planet such as this would look like, but my guess is it would be very different from ours. As soon as the inhabitants of the sea started left the water they would start evolving with the low gravity in mind, and the result would almost certainly not be us.


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