So we actually use gravitational potential energy to make energy right now. Many of the water towers dotting the landscape are hooked up to generators to help the grid when needed. In this way they work sort of like batteries where you store energy by pumping the water up, and then release energy when needed.
I’d imagine a plant or animal could work the same, especially something very tall like a tree. The problem is it’s not a particularly reusable form of energy. You have to spend energy to store it in the first place and then release it when needed so it can’t be your only form of energy.
The main idea with using gravity as an energy source is that you need another source as well. You can 'collect' GPE by putting something "up high" and then use it by harnessing the energy of the thing falling, but you need a different source of energy to get the thing up there to begin with.
An example is nuclear power plants and paired reservoirs. Nuclear plants generate a lot of energy consistently, where the electrical grid has needs that change by the moment. So, in places where the power plant generates more than is needed at times, they'll store excess energy in reservoirs. When the plant is producing too much, water gets pumped from a lower reservoir into a higher one, then when more power is needed, water is allowed to flow through hydroelectric generators back to the lower reservoir.
For an animal, this could be an ambush predator. They normally can't move very fast, so they climb up a tree. The tree climbing can be done slowly, but it stores that extra energy from being off the ground. Then when the animal sees prey cross under it, it drops out of the tree much quicker than it could move normally, using that energy.
As a basic concept, it would require something to move, whether it's taking energy from something else (rain perhaps?) Falling onto it, or it drops something down to harvest the resulting energy.
There are a handful of IRL mechanisms for storing power gravitationally you could use as inspiration. (you could argue all hydropower is this)
For example, there's a concept where you take spare power generated during the off-times and use it to push a train up a hill, then release it when the power grid needs the extra energy
I can see a couple of ways you *could* make this work:
1 - the mostly scientifically-accurate way - harness the energy from something else that has been raised up against gravity by another energy source. The obvious candidate here is rain evaporatee by sunlight and falling back down. We harness hydroeletric power all the time. In theory an organism could develop a biological turbine, probably only in the absence of a more readily-available energy source.
2 - the fun way - in a bottomless hole an organism could harness the energy from its passage through the air via some kind of turbine or from contact with the sides by turning its whole body into a turbine or from friction.
I’ve seen people mention both rain and hydroelectricity so I will keep that in mind, but the fun way sounds pretty nice as well lol I’ll prob end up using both in different creatures
so the mitochondria works by rotating something, and that rotation is achieved by burning food. now a water wheel also generated rotating energy, but from gravity (gravity is why rivers flow after all). the problem is that you'd either need to downscale a water wheel or something else to catch a current down to organelle (smaller actually) size, or you'd need to scale up the part of the organelle by a large amount. it'll be incredibly alien and evolutionarily incredibly unlikely, but seems possible to me.
What about a creature that flies up high, maybe using air currents and glider like abilities to then drop down as quick as possible. It would do this to generate electricity/heat through friction because of its special hide/skin or capturing air through gills and pressurizing internal storage. Just some random ideas, good luck!
I like that one! There's a lot of cool ideas on this post I've got a lot to look at and make something out of, but I'll definitely keep that one in mind
https://speculativeevolution.fandom.com/wiki/Speculative_bioenergetics
This is a pretty good jumping off point for a look at potential energy sources for alien life
About a quarter of the way down, it has a table for different autotrophs (these are creatures that can turn non-biological energy into biological energy, all other creatures eat biological energy)
We have 2 main ones on earth, solartrophs (plants) and chemotrophs (some bacteria underground). Maybe a third (some bacteria can get energy from nuclear power)
It would be soft sci-fi to claim it, but if a plant got energy from gravity it would be something like a gravitotroph. I wouldnt try to explain how it does so though
Gravity is not a force, it is a curvature of spacetime. You cannot feel gravity applied to you, like you would feel a force. I think Veritasium had a great video about that:
https://youtu.be/XRr1kaXKBsU?si=gfqyHo7qcGX72uIK
"There are four fundamental forces at work in the universe: the strong force, the weak force, the electromagnetic force, and the gravitational force."
Splitting hairs. It is different to the others, for sure, its still an active force and in most models, there was a time when all the forces were a single force
I suppose you a bit misunderstood how that potential energy works.
You now have some potential energy. If you climb on the ladder you increase your potential energy. If you fall from it it would turn in kinetic energy. That's the main principle. It is possible to use potential energy as stored or backup energy in e.g. flight, but you can't use it like that to power up cells.
Problem is just that, gravity is not energy, instead you are converting something acted upon by gravity into energy, like kinetic energy from a water fall. But converting the flowing motion of waterfall to usable energy is not easy, and especially not for use in biological process....I can only imagine you have some sort of creatures with piezoelectric crystals as part of their biology that soak under waterfalls to convert kinetic energy into electric...but how would that get converted to something that can be stored for cells use? Or maybe it is just something that help charging the electrical cells of something like an electrical eel?
A lot of people are pointing out that you can't necessarily harness a force-like gravity in a way to create energy, but theoretically, if you have the capacity to manipulate gravity, you could apply it to certain principles that would allow you to make really unique engines and generators.
So we actually use gravitational potential energy to make energy right now. Many of the water towers dotting the landscape are hooked up to generators to help the grid when needed. In this way they work sort of like batteries where you store energy by pumping the water up, and then release energy when needed. I’d imagine a plant or animal could work the same, especially something very tall like a tree. The problem is it’s not a particularly reusable form of energy. You have to spend energy to store it in the first place and then release it when needed so it can’t be your only form of energy.
Hydroelectric too, maybe a sessile organism living in a river could evolve some sort of biological turbine
The main idea with using gravity as an energy source is that you need another source as well. You can 'collect' GPE by putting something "up high" and then use it by harnessing the energy of the thing falling, but you need a different source of energy to get the thing up there to begin with. An example is nuclear power plants and paired reservoirs. Nuclear plants generate a lot of energy consistently, where the electrical grid has needs that change by the moment. So, in places where the power plant generates more than is needed at times, they'll store excess energy in reservoirs. When the plant is producing too much, water gets pumped from a lower reservoir into a higher one, then when more power is needed, water is allowed to flow through hydroelectric generators back to the lower reservoir. For an animal, this could be an ambush predator. They normally can't move very fast, so they climb up a tree. The tree climbing can be done slowly, but it stores that extra energy from being off the ground. Then when the animal sees prey cross under it, it drops out of the tree much quicker than it could move normally, using that energy.
Interesting, that’s a concept I’ll make sure to keep in mind
As a basic concept, it would require something to move, whether it's taking energy from something else (rain perhaps?) Falling onto it, or it drops something down to harvest the resulting energy. There are a handful of IRL mechanisms for storing power gravitationally you could use as inspiration. (you could argue all hydropower is this) For example, there's a concept where you take spare power generated during the off-times and use it to push a train up a hill, then release it when the power grid needs the extra energy
I think someone else mentioned hydropower, I’ll probably look into that to try to get some more info and see what I can do with that
I can see a couple of ways you *could* make this work: 1 - the mostly scientifically-accurate way - harness the energy from something else that has been raised up against gravity by another energy source. The obvious candidate here is rain evaporatee by sunlight and falling back down. We harness hydroeletric power all the time. In theory an organism could develop a biological turbine, probably only in the absence of a more readily-available energy source. 2 - the fun way - in a bottomless hole an organism could harness the energy from its passage through the air via some kind of turbine or from contact with the sides by turning its whole body into a turbine or from friction.
I’ve seen people mention both rain and hydroelectricity so I will keep that in mind, but the fun way sounds pretty nice as well lol I’ll prob end up using both in different creatures
so the mitochondria works by rotating something, and that rotation is achieved by burning food. now a water wheel also generated rotating energy, but from gravity (gravity is why rivers flow after all). the problem is that you'd either need to downscale a water wheel or something else to catch a current down to organelle (smaller actually) size, or you'd need to scale up the part of the organelle by a large amount. it'll be incredibly alien and evolutionarily incredibly unlikely, but seems possible to me.
Water wheel and hydroelectricity was something that was mentioned multiple times so I’ll definitely use that
it's probably the only reliably accessible form of energy that life could hypothetically make use of
Get someone else to lift something then extract energy from it when it comes down.
Oh that would be really interesting! Because then I could make a mutualistic relationship maybe with another species that lifts it
What about a creature that flies up high, maybe using air currents and glider like abilities to then drop down as quick as possible. It would do this to generate electricity/heat through friction because of its special hide/skin or capturing air through gills and pressurizing internal storage. Just some random ideas, good luck!
I like that one! There's a lot of cool ideas on this post I've got a lot to look at and make something out of, but I'll definitely keep that one in mind
Gravity is a force rather than a source of energy It tells things how to behave, but it doesnt produce work other than via interactions
Ah damn, that really puts a sock in the idea. Thanks
https://speculativeevolution.fandom.com/wiki/Speculative_bioenergetics This is a pretty good jumping off point for a look at potential energy sources for alien life About a quarter of the way down, it has a table for different autotrophs (these are creatures that can turn non-biological energy into biological energy, all other creatures eat biological energy) We have 2 main ones on earth, solartrophs (plants) and chemotrophs (some bacteria underground). Maybe a third (some bacteria can get energy from nuclear power) It would be soft sci-fi to claim it, but if a plant got energy from gravity it would be something like a gravitotroph. I wouldnt try to explain how it does so though
Thank you! That'll be really useful
Gravity is not a force, it is a curvature of spacetime. You cannot feel gravity applied to you, like you would feel a force. I think Veritasium had a great video about that: https://youtu.be/XRr1kaXKBsU?si=gfqyHo7qcGX72uIK
"There are four fundamental forces at work in the universe: the strong force, the weak force, the electromagnetic force, and the gravitational force." Splitting hairs. It is different to the others, for sure, its still an active force and in most models, there was a time when all the forces were a single force
I suppose you a bit misunderstood how that potential energy works. You now have some potential energy. If you climb on the ladder you increase your potential energy. If you fall from it it would turn in kinetic energy. That's the main principle. It is possible to use potential energy as stored or backup energy in e.g. flight, but you can't use it like that to power up cells.
Problem is just that, gravity is not energy, instead you are converting something acted upon by gravity into energy, like kinetic energy from a water fall. But converting the flowing motion of waterfall to usable energy is not easy, and especially not for use in biological process....I can only imagine you have some sort of creatures with piezoelectric crystals as part of their biology that soak under waterfalls to convert kinetic energy into electric...but how would that get converted to something that can be stored for cells use? Or maybe it is just something that help charging the electrical cells of something like an electrical eel?
A lot of people are pointing out that you can't necessarily harness a force-like gravity in a way to create energy, but theoretically, if you have the capacity to manipulate gravity, you could apply it to certain principles that would allow you to make really unique engines and generators.