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Like fossil fuels come from organic matter that grew because of the sun. Is there any form of energy on that cannot be traced back to the sun in some way?

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[–] [email protected] 98 points 2 weeks ago* (last edited 2 weeks ago) (4 children)

Almost.

  • Nuclear energy comes from natural materials of the earth that arrived in their current form (it is basically recycled supernova energy from long long ago)
  • Geothermal comes ultimately from the gravitational energy of the earth itself compressing and heating it

Literally every other energy source (edit: aside from tidal and some others that people pointed out) is some form of modified and stored sunlight, in some way or another.

[–] [email protected] 22 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

Although geothermal could be because of the rotation of the earth compared to its core along with tidal forces.

Although I’m not sure how much of that is from the sun or just in general.

Not sunlight though. Just the sun’s gravitational affect on the earth as well. But nuclear is definitely extrasolar

[–] [email protected] 6 points 2 weeks ago

It could be, but it's not. A big part is nuclear decay, strangely enough. Some is from primordial heat, and some is from the motion of the core, but mostly from regions rising and falling, not rotation.

[–] [email protected] 18 points 2 weeks ago (5 children)

There is also kinetic energy when objects in space crash into the earth. RIP 🦖🦕

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[–] [email protected] 10 points 2 weeks ago (1 children)

Geothermal comes ultimately from the gravitational energy of the earth itself compressing and heating it

One thing that’s at least 97-percent certain is that radioactive decay supplies only about half the Earth’s heat. Other sources – primordial heat left over from the planet’s formation, and possibly others as well – must account for the rest.

https://newscenter.lbl.gov/2011/07/17/kamland-geoneutrinos/

A surprising amount of geothermal energy comes from radioactive decay. Gravitational binding energy is indeed very large, but much of that heat has already radiated away before a solid crust formed.

[–] [email protected] 2 points 2 weeks ago (2 children)

But it sounds like, based on other comments, those things are from stars too, right? Like the sun caused the formation of our planet. It also contributes to tidal forces. And radioactive materials also came from other stars if not our own star. Right?

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[–] [email protected] 3 points 2 weeks ago

To add to this most of the suns energy leaves the planet. Very little is retained. What the sun provides is a source of low entropy.

[–] [email protected] 48 points 2 weeks ago* (last edited 2 weeks ago) (9 children)

Geothermal, which at this point in geological history mostly comes from decaying radioactive elements. It's of minor industrial importance, but it fuels undersea vent ecosystems, and does see some use in traditional cultures.

Speaking of radioactive elements, our nuclear generators all run on energy trapped from ancient cosmic catastrophes. Probably colliding neutron stars, for the most part. Hydrogen fusion has been made to happen for research and in atomic bombs - although interestingly we can't use the same kind as the sun does.

Tidal energy is used for some power generation, and it comes from the kinetic energy left in the Moon, and to a lesser degree the Earth itself, from the formation of the solar system.

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[–] [email protected] 35 points 2 weeks ago (2 children)

Nuclear (fission) energy did not originate in our sun, it originated in some other sun a long time ago, or potentially a neutron star merger.

Tidal energy originates from gravitational collapse and the conservation of angular momentum when our planet and moon formed, and does not rely on our sun, but similarly originated in the dust clouds that formed our solar system which were put there by some other sun.

Geothermal is a hybrid of these two, with some combination of nuclear decay heating and gravity-driven heating.

Hydrocarbon, wind and hydroelectric all heavily involve our sun somewhere in the process though.

[–] [email protected] 5 points 2 weeks ago (1 children)

Tides are from the pull of the moon's gravity. And the moon formed from another body colliding with the Earth. It's not just due to angular momentum and the moon forming out of cosmic dust like the Earth did.

[–] [email protected] 10 points 2 weeks ago

Without angular momentum it would have fallen back down to the Earth instead of going into orbit. It's the orbit specifically that powers the tides, not just it being there.

But yeah, you're right. Beyond providing the materials dust was not involved.

[–] [email protected] 3 points 2 weeks ago (2 children)

Tides don’t rely on the sun but are affected by the sun.

[–] [email protected] 3 points 2 weeks ago

They said “tidal forces,” not “tides.” Tidal forces refer to the differential of gravitation between two points on an object. It applies in any situation where gravity is a factor, although typically only very large massive objects experience noticeable effects. That said, the concept of spaghettification (objects being stretched out as they approach a black hole’s event horizon) is based on the fact that tidal forces near a black hole would be so enormous they would be observable for even small objects like people.

[–] [email protected] 2 points 2 weeks ago

Hm. Touche.

[–] [email protected] 15 points 2 weeks ago (2 children)

Everyone is giving you some great answers, but there are since more subtle ones worth mentioning too.

When you take a picture of space, the light from those other stars hits the camera sensor and induces a tiny electrical charge, which is captured, amplified, and analyzed to create the image. Your eyes actually work that way too.

It's not an energy source as you typically think of it; it never powers anything, but technically it is* energy that exists on Earth that didn't come from our sun.

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[–] [email protected] 11 points 2 weeks ago (1 children)
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[–] [email protected] 9 points 2 weeks ago (1 children)

Geothermal comes from the heat in the core, produced by gravity crushing the particles together during the Earth's formation.

Nuclear energy comes from the fission and fusion of particles here on earth.

Tidal energy comes from the gravitational pull of the moon.

Hydro comes from the movement of water (though you could trace this back to the sun causing the water cycle).

[–] [email protected] 4 points 2 weeks ago (1 children)

Earth wouldn't coalesce without the sun. Thus no geothermal.

Nuclear materials were formed in supernovas. Can't have that without a star.

Moons tides wouldn't exist if Earth didn't have an orbit of its own. Again, sun needed.

Hydro you already figured out.

[–] [email protected] 6 points 2 weeks ago (1 children)

I guess it depends on how far back you want to go. The sun wouldn't exist without gravity.

[–] [email protected] 2 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

Well, seeing as how the question is directly asking "is there any energy you can't eventually trace back to the sun", you shouldn't ever stop going back unless you can reach a definitively non sun answer

(Gravity arguably works - probably the nuclear attraction force as well, electromagnetic I believe)

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[–] [email protected] 7 points 2 weeks ago (1 children)

Where did the Sun's energy come from?

[–] [email protected] 19 points 2 weeks ago (2 children)

The gravitational collapse of a cloud of mostly hydrogen in the vacuum of space.

And anything falling together under gravity was given that kinetic energy from somewhere* and ultimately it can all be traced back to the Big Bang.

As for where that energy came from, it's possible we'll never know. Most organised religions (and no doubt a few disorganised ones) have their theories, of course. You may subscribe to one of these.

* This is the principle most commonly simplified as "what goes up, must come down"

[–] [email protected] 8 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

What's really interesting is that "what goes up, must come down" doesn't hold at the scale of the universe. A naive thinker might imagine big bangs happen in cycles, but in fact this doesn't appear to be the case, because space itself is expanding faster than galaxies are falling back together. And it's not just faster now, but it's accelerating! At some point, space will be expanding faster than the speed of light, and because of that, the entire universe will disappear from our view.

Despite that, the Milky Way galaxy is still close enough to the Andromeda galaxy that they'll collide in about 5 billion years, so don't worry, there's still interesting things to come! If you want to see it, though, you'll need to be somewhere other than Earth, because by that time the Sun will have advanced in its life cycle enough to render Earth completely uninhabitable by all known forms of life.

[–] [email protected] 4 points 2 weeks ago (3 children)

Just to add onto this comment, it's thought that the Sun is slowly getting hotter and more energetic as it gets older and in approximately 1 billion years, the Sun will be hot enough to render the Earth uninhabitable for life as we know it.

In approximately 5 billion years, the Sun will reach the end of its life and expand into a red giant, swallowing up Mercury, Venus and potentially Earth in the process. Interestingly, once the Sun reaches this phase of its life, it could potentially warm up some of the outer moons enough for them to have liquid water, if they can hold onto an atmosphere of course.

Someone please correct me if I said anything wrong, I'm just a casual space nerd and not a professional astronomer.

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[–] [email protected] 2 points 2 weeks ago

Brane cosmology suggests the collision of two branes can result in a big bang event, but yes, that is beyond an event horizon.

[–] [email protected] 6 points 2 weeks ago

No, geothermal energy comes from the earth core for example.

[–] [email protected] 5 points 2 weeks ago* (last edited 2 weeks ago) (2 children)

It'd be interesting to think of novel ways of getting power from sources other than the Sun.

Theoretically, one could, say, build a space-elevator-like device and use the centrifugal force pushing it away from Earth to run a generator. Of course, for that to work, the weight would have to continually receed from Earth, and may require continually replacing the weight. Ultimately that would rob the Earth of angular momentum.

[–] [email protected] 4 points 2 weeks ago (1 children)

Wouldn't that technically be from the sun, too, though? Since the earth orbits the sun due to its mass/gravitational pull?

[–] [email protected] 6 points 2 weeks ago* (last edited 2 weeks ago)

What I posted would take energy from the angular momentum of the Earth rotating on its own axis, not the (angular?) momentum of the Earth revolving around the Sun.

Honestly, I'm not 100% sure the right way to talk about where the Earth's angular momentum about its own axis came from. I want to say gravity while the Earth coalesced from dust/gas, but I'm not sure that's quite true because I think the gravity would only kindof "concentrate" the angular momentum that was already present in the gas/dust that was already present in the cloud. (Like, when an ice skater pulls their arms toward their body and speed up, that doesn't add energy or momentum to the system that is the ice skater.)

So, maybe it's more accurate to say it's kinetic energy from the Big Bang and/or supernova(s?) that produced the gas/dust that eventually formed the Earth?

But I'm pretty sure this scheme would get energy from a source that wasn't ultimately from the Sun.

[–] [email protected] 4 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

That feels like a perpetual motion machine, because the Earth coming together in the first place released energy. I'm guessing it would take more energy to get the weight to geostationary orbit than you could get back.

Maybe it would work if you lowered an asteroid down, instead. And then you could mine it on arrival.

Edit: Nope, it maths. I think it's down to angular momentum being kind of separate from the gravity well.

[–] [email protected] 3 points 2 weeks ago (1 children)

So, first off, I'm definitely not arguing this would be a feasible way to get energy in a practical sense in the real world.

But, it wouldn't be a perpetual motion machine. It'd produce less and less energy as the Earth ran out of angular momentum, ultimately approaching zero.

I don't think I'll do the monster math on this, but my gut tells me one could technically and theoretically (not so much in practice) get more energy out of that than it took to get the weight up there. (It might be that the Moon would limit how much energy could be got out of this scheme as well, but I think even with the Moon involved, I think it could still be a net energy gain.) That said, without running the numbers, you might well be right!

[–] [email protected] 3 points 2 weeks ago (2 children)

Ah shoot, it looks like you posted a minute after my edit, and probably didn't see it.

Orbital mechanics is big-boy stuff, and gets really subtle the moment you're doing anything non-trivial. This is just two-body, so in theory it should be doable, but the tether pulling out energy as it goes along makes it more complicated. It's a bit much tonight, but maybe I'll give it a shot later. One thing that's clear just from the equation for orbit energies is that there's no limit to how much energy can end up inside the weight itself, as it gets faster in proportion with increased height.

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[–] [email protected] 5 points 2 weeks ago* (last edited 2 weeks ago) (2 children)

https://youtu.be/N1pIYI5JQLE?si=uciOf3JzwF8S6qDy

Y'all need to pay attention to the actual question being asked. Geothermal, nuclear, tidal are all originating with the formation of the galaxy and the formation of stars.

Ask yourself: WHERE did the earth get X,Y,Z? Where does nuclear materials come from: supernovas. How do planets form? A gas cloud coalesces, the star forms, and the remaining gasses coalesce in that gravity well formed by the star. Without a star forming in the middle, you get no solar system. You get cold blob of gas or a cold dead rock. Where does tidal come from: same gravitational interactions that require a sun sized object - tides aren't 100% earth & moon.

Stars are like the seed needed to form crystals. Without them, nothing else forms. Just a bunch of basic chemicals floating around.

[–] [email protected] 3 points 2 weeks ago (1 children)

OP said the sun, indicating they meant our sun. Other commenters have clarified that fissile material (and a shit-ton of the other stuff further down the periodic table) didn’t come from our sun, but other suns.

[–] [email protected] 2 points 2 weeks ago

I mean ya okay I see that. But still very neat that all energy in every form we have can be traced back to a star if not our own star. That’s so interesting! Let’s get started on the Dyson sphere.

[–] [email protected] 2 points 2 weeks ago

That video was above my pay grade I think. But ya I like what you’re saying here. Sounds like all of our energy does come from a star if not our own star

[–] [email protected] 3 points 2 weeks ago (4 children)

The heat in the Earth's mantle and core comes from the gravitational potential energy of the original stellar dust clouds the Earth originally accreted from. So, geothermal energy mostly isn't. And there's also evidence that a few natural uranium deposits have undergone natural nuclear fission chain reactions. That one's a pretty negligible amount, though. Other than that, no, it all traces back to the sun.

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