If there is a planet, like earth which is 10 times the size, will the life forms be 10 times larger also?

Question

i.e. Greater gravity, Giant Life forms?

Answer 1

This is a great question. Nice work.

Clearly, gravity influences evolution. On Earth, species have developed endo and exo skeletons to support their squishy organs under the pull of gravity. (There are small organisms that have no skeletons at all...like amoebas.) Without these hard bones or shells, the organs could not function, there would be no life for multi-celled organisms like mankind.

On Planet X, which is 10 times the size of Earth (assuming the radius of the new planet is ten times the radius of Earth), gravity would be about a 1,000 times greater than that of Earth if Planet X is made up of stuff similar to Earth's core and mantel. That result follows because Planet X would have 1,000 times more mass than Earth; mass is what curves space and gives us the effect of gravity.

So my guess is that under 1,000 times more gravity, the skeletal systems of species evolving on Planet X would be way stronger than those found on Earth. One way to do this, using the same skeletal materials found on Earth, would be to develop thicker (larger) bones or shells. In which case, Planet X creatures would likely be wider (thicker), but shorter than Earth creatures. They would likely be shorter because the intense gravity would discourage growth upward away from the gravitational pull.

Perhaps another question to ask in this regard would be "Could life as we know it start and evolve under gravity 1,000 times greater than that of Earth?"

Answer 2

Probably not, I would have thought they would be much much smaller than life on earth because the gravity will be much greater for a world 10 times as big (10 times the mass?), so there would be no advantage in expending energy to grow big and be acted upon by the enormous gravity of a X 10 world. I'm not sure that the gravity equation is a straight ratio of size to gravity either, I think the ratio of gravity to attraction is a squared function (gravitational pull decreases at a rate of the square of the distance apart, as bodies move away from each other).

Answer 3

When you increase the size of something, it doesn't lead to a corresponding increase in other properties.

As an example consider this cube:
The cube is 1cm high, 1cm wide, 1cm deep. Its volume is found to be 1 centimetre cubed (i.e. 1cm^3), by multiplying the height by the width by the depth (1cm x 1cm x 1cm).
Now imagine that this cube is made of steel (it doesn't really matter what it's made of for this example). The density of steel is about 8 grammes per centimetre cubed, therefore this cube weighs 8 grammes.
Now imagine that you make the cube 10 times the size - 10cm x 10cm x 10cm. Now its volume is 1000cm^3 and its mass is about 8000 grammes (8 kg).

Now imagine you have two cubes side-by-side. The force due to gravity between two 1cm cubes is proportional to (8g x 8g) / (1cm x 1cm). You can work this out to give you a force between the cubes of 42.7 pico-Newtons.
However the gravity force between two 10cm cubes is proportional to (8000g x 8000g) / (10cm x 10cm). The force between the cubes increases to 427000 pico-Newtons.

So the mass, and hence gravity does not increase in line with the dimensions of an object (e.g. a planet).

Also, as far as we know, the sizes of fundamental particles (the things that make up atoms) is not different on other planets. This means that the fundamental mechanisms that govern growth, for example, would probably be the same.

So on this basis I would say no - there might even be a lower maximum-size that a life form can take in high gravity, compared to Earth. But then it's not really a solid basis for drawing conclusions.

After all, there were giant life forms on Earth (e.g. dinosaurs, or those massive squid they've found), and there are also really tiny life forms.

Here's my conclusion: there probably would not be any birds.

Answer 4

I'd imagine any lifeforms would have to be a lot smaller than here on earth. If the planet was ten times the size of earth, then its gravity would be 10 times greater. So it would be very difficult for anything to grow that large as its bones would not support its weight. Unless of course its an odd alien race whos bones are made from titanium.

Answer 5

It would depend on the density of the planet. Since gravity is an inverse square law, the gas giant in our own solar system to not have as high an acceleration of gravity as you might expect. Organisms must work against gravity to circulate nutrients and gases through the body. But lower gravity does not necessarily mean taller or larger organisms. The other factors are the conditions on the planet itself such as available food, water, weather, sunlight, etc. These factors must also be considered.

Answer 6

for animals assuming that muscle types there would have much the same power to weight ratio as here, then for creatures on land, more likely they would be very much smaller, but in the oceans where buoyancy effects cut in, there would seem no overriding reason why sizes similar to aquatic species here could not be achieved, but 10 times larger, unlikely. in the air the situation is more unclear. for though birds and flying insects would weigh a lot more, the atmospheric pressure would be correspondingly greater, and instead of winged creatures flying they would more likely swim through the thicker atmosphere. but again, 10 times larger, no, almost certainly, smaller and flatter would be the key to survival for both plantlife and animals on a high gravity planet, tho for bacteria and so forth, they probably wouldnt be too bothered.

Answer 7

Actually, the opposite. Greater gravity may impose smaller animals. Like an ant can lift several times its own weight because it is small and benefiting from the scale factor (shrink size by a factor of two, and the weight goes down by a factor of 8, but the strength which is a function of the diameter of a muscle, goes down by a factor of 4 only, so you are proportionally twice as strong. Elephants could not support a load has heavy as their own body, and whales cannot survive their own weight, they need to float to survive). This applies to plants and animals equally.

That is, unless the biology of those hypothetical alien uses matter differently and have bones that are much stronger than ours.

Answer 8

There will never be a 30 foot tall spider because it could never support itself.

Things get heavier by the cube of their height. They get stronger by the square of their height. So, if I were to double my height and all my other linear dimensions, I would be 8 times heavier but only 4 times as strong.

So, how do you increase your mass to strenght ratio? You get smaller. That is how an ant is able to lift things 10 times his size and a flea can jump 200 times his own body length.

Greater gravity could result in possibly less dense life forms, smaller life forms, life forms made out of different, stronger materials. But, it is unlikely that they would be larger unless we were talking about a liquid environment where they wouldn't have to support their own weight.

Answer 9

They could be 10 times larger, but because of less gravity, not more. Carrying extra size would take less energy, meaning less of a requirement for food.

Actually, your question isn't quite specific enough. What do you mean by 10 times larger?

Do you mean the same mass, but the radius is 10 times larger? Gravity on the surface would definitely be less.

Do you mean 10 times the mass, but the same radius? Gravity would be stronger on the surface, meaning large animals would be less likely.

Do you mean 10 times the mass and 10 times the radius? Gravity would be less and larger animals could exist. (Gravitational force equals GMm/r^2. Increasing the radius decreases gravitational force faster than increasing the mass increases gravitational force.)

Do you mean a larger size with the same density? This would make the gravitational force 10 times as large, but the total mass would be 1000 times as much.

Edit: This was edited. Jupiter's gravitational force isn't nearly as strong on the surface as you might expect, since it is less dense, but it would still be greater than Earth's (about 2 1/2 times stronger).

Answer 10

no. the life forms on a planet 10 times the size of earth would develop to be much nearer to the ground, because of the increased pull of gravity. they would have no reason to be larger; if anything they would be smaller to counter balance the great pull from the planets core.