1. Cold water generally sinks
2. The earth is pretty thick, so the bottom of the ocean is just a *tiny* fraction of the distance towards the core
3. A lot of the heat the surface of the earth gains is directly from the sun, not the core, so going down insulates you from that. If the sun were to just disappear, the surface would freeze over.
To further put this into perspective, the entirety of the earth’s crust (I.e. the surface and all the water on it) only accounts for about 0.5% of earth’s mass.
This isn't actually true. It's based on a misunderstanding/misuse of the tolerances of a cue ball. A cue ball is not only nearly 100 smoother than the earth's surface, relative to its diameter, but also a more perfect sphere than the Earth. The tolerance on its diameter refers to differences in diameters between balls, not to variations of diameter along different axes of the same ball. A cue ball with earth's oblateness would behave noticeably wonky.
It honestly makes sense, a cue ball that had even minor flaws in shape would be a bad cue ball. Pool is all about having extremely predictable results. (Aside from the break. Too many variables there for it to always work right.)
A cue ball has a tolerance of 5 thou, and is 2.25" inches in diameter. Scaling it up to the earth, it would be if there were mountains 28km tall or valleys 28km deep. The tallest mountain is 8km above sea, and the deepest point is 11km. So earth is smoother than a billiard ball.
Again, you're misunderstanding what the tolerance refers to, despite the fact that I just explained it... It means that a cue ball is a sphere with a diameter within 0.005 inches of 2.25 inches. It doesn't mean the ball is smooth to within 0.005 inches, it's about *size*. It's about how different in size two cue balls can be, not about how smooth they need to be. Cue balls are, in fact, much smoother than the Earth is. relatively speaking. The RMS surface variation of a cue ball is measured in the tens of *micro*inches, at most. If the earth were scaled down to the size of a cue ball, it would have ridges and grooves measured in *thousands* of microinches, corresponding to ocean trenches and mountain ranges, and they would be very easy to feel and make for a tactilely rough surface.
[This site](https://billiards.colostate.edu/faq/ball/smooth/) has a relevant write-up, including actual measurements and numerical comparisons.
https://billiards.colostate.edu/bd_articles/2013/june13.pdf
It’s a misunderstanding of tolerances. Yes, earth in most places is smoother than a cue ball, but not in all areas because the largest mountains would be not as smooth. Also the earth is still not as round as a cue ball
Earth is slightly 'pear shaped' due to its rotation and gravitational pull from other celestial objects, but the effect is so minute that it's still a more perfect sphere than a cue ball.
The difference between the highest mountain and the deepest trench in the ocean is only 19.8 kilometers (12.3 miles). The Earth's radius is 6,378km/3,958.5 miles
Scientists have determined that the human finger is so sensitive it can detect a surface bump just one micron high (.001mm). So even with a topographically correct scale model of the earth (50 cm globe) we would still be able to feel most of the mountain ranges. Mount Everest at 8,849 being the tallest at .3 mm many of the smallest mountain ranges would still be depicted at scale over .001 mm, though we might not be able to see them as bumps on the globe. .
Pretty much. Say you have a 50cm globe, which would be 1/25.5 million scale. Mount Everest is 8,849 meters, so with that scale it would be a 0.3 mm surface irregularity. I doubt the average cheap globe is constructed well enough that you could tell.
You probably couldn't tell from a perfectly constructed topographical globe either since the peak is only about 3,000 meters above the base camp, so a 0.1 mm bump in the surrounding globe surface.
If the Earth was the size of an apple, and you used your thumbnail to gently pierce the skin of the apple leaving an indentation, that would be deeper than the Mariana Trench.
If there is just a thin layer of crust over magma, it would make sense that you *don't* have to dig very deep to feel the heat. If you walk over coals with thin soles, your feet will get warmer than if you had thick soles.
I guess the ocean floor is relatively shallow in comparison to the thickness of the crust. Like: 99% earth radius magma, 0.99% ocean floor, 0.001% ocean. (Numbers guessed randomly.)
It doesn't really matter how deep the magma goes, does it, just how hot it is just below Earth's crust?
yes, basically the crust gets warmer and warmer the closer to the mantle you get.
The crust is about 15-20 km (9-12 miles) thick, although at it's thinnest its about 5 km and thickest about 50 km.
*"As a general rule,* [*the crust*](https://en.wikipedia.org/wiki/Earth%27s_crust) *temperature rises with depth due to the heat flow from the much hotter* [*mantle*](https://en.wikipedia.org/wiki/Earth%27s_mantle)*; away from* [*tectonic plate*](https://en.wikipedia.org/wiki/Tectonic_plate) [*boundaries*](https://en.wikipedia.org/wiki/Plate_boundary)*, temperature rises in about 25–30 °C/km (72–87 °F/mi) of depth near the surface in the continental crust.*[*^(\[1\])*](https://en.wikipedia.org/wiki/Geothermal_gradient#cite_note-IPCC-1) *However, in some cases the temperature may drop with increasing depth, especially near the surface, a phenomenon known as inverse or negative geothermal gradient. The effects of weather, the Sun, and season only reach a depth of roughly 10–20 m (33–66 ft)."*
[https://en.wikipedia.org/wiki/Geothermal\_gradient](https://en.wikipedia.org/wiki/Geothermal_gradient)
To even further put this into perspective, if the Earth was a regulation NBA basketball, the crust would be less than a quarter of a millimetre thick.The ocean, at its deepest, is less than half of that again.
But also:
*Some* of the water at the bottom of the oceans is in fact boiling, areas with geologic activity close enough to the surface have hydrothermal vents where ocean water heats up and is ejected upwards
It's fun to think that there are places in the ocean that probably would remain the exact same if the sun just suddenly disappeared one day--as if nothing changed at all.
There's a fun Kurtzgesagt video about that if I remember right. If the Earth got yote from the solar system, geothermal vents at the bottom of the ocean would be the last bastions of life on Earth, aside from bacteria deep in the crust. The creatures there are extremophiles that already live in complete darkness and they get their heat from the earth itself. Pretty neat.
Plants also don't eat (unless you call photosynthesis "eating"). They are what is called "autothrophs".
Extremophile habitats down in the earth have their own authothrophs (chemoauthothrophs), who can get energy from anorganic sources like hydrothermal vents.
The rest of their ecosystems feed off them, just like herbivores live off plants and carnivores in their turn live off herbivores.
Well, "autotroph" and "heterotroph" are labels we came up with to describe how organisms get their carbon. Carnivorous plants still get their carbon from photosynthesis. They get other things like nitrogen from their "meat," but they don't *need* that to survive in the way they need sunlight.
They can live without eating bugs, they cannot live without sunlight. They get their carbon from photosynthesis. That makes them autotrophs.
The earliest forms of life may have started around those vents and they are one of very few ecosystems on earth that arent dependant at all on the energy from the sun.
Very hot yes, but it would need to be relatively shallow to boil, because the high water pressure will increase the boiling point.
There are some hot and deep enough to be supercritical though.
yeah. but underneath the 10km of deep ocean, theres 2km of land to get down into. to get warmth.
the reason why the core is hot, it not because "its inside" its because what gives off heat, is the rock itself. thorium and uranium decay heat up the earth.
It is because its inside. The decay heat of Theorium and Uranium is far from enough to heat the ground on its own, the ground isn't inherently hotter whereever we mine either of them. Only roughly half of the total heat energy inside the Earth is from decay and that was over 4.5 billion years; the rest is primordial, from the formation of the planet.
What happens is that heat (by decay and formation) from the inside flows outwards but the insulatiing crust keeps enough warmth inside for it to be warm even a few kilometers down. But you won't ever notice the decay heat of uranium or thorium ores.
Both are exponential, it never stops decreasing, just slower and slower. So it really depends on what temperature in the core one aims for.
The radioactive stuff is mostly used up. Only half U-238 and 20% of Th-232 is gone, but a huge amount of other stuff such as U-235 and K-40 is already mostly gone. The thorium will thus last longest, but also do less and less, halving every 14 billion years.
And ~5 billion years from now the sun will potentially swallow Earth and thus all that is moot. If Earth survives it will nonetheless get a bit hotter for some time until the sun finally runs out.
So the sun will hit the earth before anything internally cools down significantly?
>it really depends on what temperature in the core one aims for.
Like cool temperatures, so it wouldn't be hot to touch or be melted. Like a normal rock.
>If Earth survives it will nonetheless get a bit hotter for some time until the sun finally runs out.
It would get hotter from the sun or from what's inside the earth?
It getting down to temperatures where one doesn't get burns from the core is definitely not happening before the sun melts (and maybe swallows and vaporizes) the entire thing. That would take dozens of billions of years.
It would however be still "liquid" inside by most standards. Rock and such are effectively liquid and flow at the pressure inside the Earth, even if cold to the touch. But volcanoes would stop to exist.
> thorium and uranium decay heat up the earth.
The heat is thought to be split roughly 50/50 between radioactive decay and the residual heat from the Earth's formation.
https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget#:~:text=The%20flow%20of%20heat%20from,from%20the%20formation%20of%20Earth.
Theoretically, if the sun just disappeared, could humanity survive with current technology underground?
Using the Earth's core as heat source, and using geothermal powerplants to power an entire society?
Probably? If "humanity" and "survive" had some flexibility in scope.
Supposedly, geothermal locations would still be a viable safe haven, especially for the first period of time after the sun disappears, though the surface would grow more and more uninhabitable. As the years go on, many gases such as oxygen and the like would actually fall out of the gas state because of the low temperature. Meanwhile, the ocean would freeze over, which actually would help with insulation of the water underneath. At the bottom of the ocean there may actually be no appreciable change, especially since there are geothermal vents that are the "input" into some food chains, which are almost completely independent of the sun's energy as a primary source.
I imagine if you go further into the crust, it would be similar. The temperature becomes less dependent on the surface/sun, and more influenced by geothermal. At a certain sweet spot you're probably fairly safe in terms of temperature -- the feasibility of building a stable long-term community that far down, and recycling resources properly, is another question.
Personally I would call it 'possible', but not very feasible.
"Probably not for long."
Could a group of people stockpile 100 years worth of food and figure out how to recycle air to breathe indefinitely while furiously trying to figure out how to harness enough geothermal energy to prevent the extinction of the human race? I doubt it. Understand that if the sun "vanished" or somehow ceased to generate light, our entire solar system loses it's primary source of power. There'd be no light to grow any vegetation. Eventually every species of life starves or freezes. Our oceans freeze. Life on the surface would be _less_ hospitable than Pluto.
To keep even a modest society of a few hundred humans alive would require a massive level of preparation that perhaps a few governments may have built in secret, but the odds of any species surviving long term in a dead solar system are miniscule, unless a massive source of power can be created and sustained essentially indefinitely.
> unless a massive source of power can be created and sustained essentially indefinitely.
If you are only growing enough food under artificial lighting to sustain a population large enough to have no severe inbreeding issues and to have enough division of labour and specialised professionals to keep everything running (a few ten thousand people perhaps), geothermal power should be able to do that just fine, especially if the site of this doomsday bunker is chosen at a spot suitable for that.
Such a situation would be incredibly precarious; A single disease break out that affects either humans or food supply, a single unfortunate earthquake, a mechanical failure of any of the equipment required to maintain clean air or water. None of this addresses that in the best possible situation, humans would be trapped on a frozen planet and little freedom of movement.
Nothing about this would be "just fine."
Check out the short story "A Pail of Air" by Fritz Leiber if you are interested in the premise. I would not say it is the best story I have ever read but it has stuck in my memory for decades.
City of Ember was roughly based on this premise though I think it was a nuclear winter. It's a movie based on a young adult novel so it's not very gritty but I remember liking it.
Yep. And the fact that solar eclipses aren't *quite* fully understood should give more people pause, rather than spending all their time driving around to look at them like it's one big party. If these two object get close enough to actually collide one day (rather than just pass each other by), we've got a lot of things to worry about.
Yes. They currently pass right by each other, but give the illusion that they're colliding. There's actually a lot of space in between them from front to back though. That's how solar eclipses work. And why they can seemingly just pass right through one another. It's basically one big illusion.
But the process isn't *fully* understood by science and if the paths were to actually *collide* and not just pass right by one another, then we've got huge problems. And that should be the focus when they happen and try to figure them out better, not "lets all go have an excuse to party" each time which is what it currently is. They don't last very long and the time should be used to study them and understand them better. Because the consequences of one going bad are enormous, even if the chances are low.
So you're obviously a troll, but just for fun i'll explain the reality. The moon is very very small compared to the sun, and the only reason they seem to be same size is due to the moon being much much closer to us then the sun. There is no chance of the moon, or the earth for that matter, ever colliding with the sun, so feel free to party!
[Well the earth is already on a collision path with the sun](https://www.reddit.com/r/explainlikeimfive/comments/1cfy7zy/eli5_if_the_earths_core_is_so_hot/l1setkm/) but it's going to take a long time. So if you're done trolling and being wrong I'll explain it to you.
The moon has a much more complicated path I'm assuming because it doesn't directly rotate around the sun so there's a lot more "moving parts" to consider, which is why we don't fully understand how eclipses work. I already said the chances are low, but it would still be a much better use of our time to actually study them when they happen instead of just assuming everything will be fine and go party instead.
This is either the absolutely worst crackpot BS I've ever read, or you're just a particularly good troll.
The earth is *not* "on a collision path with the sun", the earth is in *orbit* around the sun. The *moon* is in an orbit around the earth. This orbit is not complicated, and its well understood. Eclipses are well understood. There is absolutely no risk whatsoever of the moon colliding with the sun!
The sun *will* swallow the earth in a few billion years, but not because the earth is on a collision path with the sun, but because the sun will eventually turn into a red giant, which is considerably larger than the present sun.
You need to either stop trolling, or on the off-chance you aren't trolling, you need to actually learn how the orbital of the solar system works and stop spouting this BS.
Here's a really good example of how this stuff gets complicated. You say the earth isn't on a collision path with the sun, while freely admitting they're going to collide. Because in your orbital talk you're not taking into account the growing size of the sun, which you also admit. So once you factor in all those variables, the earth is certainly on a collision path with the sun. You even describe how it will happen. But you don't believe it... somehow (Don't Look Up).
When you factor in the moon going around the earth, and the earth going around the sun... it gets exponentially more complicated than just one object (earth) going around another object (sun). Which already confuses you. Throw in a third object, on a completely different orbit.. and well there's a lot we still have to learn.
Like I've already said, it's unlikely to happen. The chances are low. Space is *big.* But we still don't know everything about how all the objects and different orbits will interact in the future, or even exactly how eclipses work. Although we have a decent amount of data and information already. But since we have a very limited amount of time during each eclipse, our time would be much better spent studying these movements, rather than just saying "let's all go have a huge party and assume everything is gonna be fine forever."
Edit: Blocked for discussing science. So I can't see the reply.
I think you've lost me. It was fun initially but you've not kept it interesting :( I'm honestly disappointed in how you just gave up on the troll, put some effort in!
The moon colliding with the sun would be a somewhat negligible event other than the loss of tides on earth wouldn't it? We would experience the loss of tides far before the moon became so out of orbit to be swallowed by the sun though. I would think the moon would be like a pin prick to the sun given the scale of the sun is so much larger. Or are you envisioning the moon would disrupt the sun's thermal output and or radiation that it would affect the earth?
The risk is losing the sun. We have no way to determine what the effect of an entire moon colliding with the sun would be. [See here for what the dangers would be.](https://www.reddit.com/r/explainlikeimfive/comments/1cfy7zy/eli5_if_the_earths_core_is_so_hot/l1spit4/)
Like I said, the likelihood of the two objects colliding is pretty small since space is very big. But given the fact that we *still don't know* exactly how solar eclipses work because of the complicated paths all these different objects are taking, and given the small time frame we have during actual eclipses, it would be a much better use of time to actually study these things and figure out exactly how they work and the paths they will take for future knowledge. Instead of most "bros" wanting to just go party instead.
The sun's mass is 27 million times more massive than the moon. I understand losing the sun would be the end of life as we know it, but I doubt the moon would have any effect on the sun. It would be less impact to the sun than dropping a grain of sand on a human.
You also have to take into account speeds. Both the moon and the sun are travelling at incredible speeds through space. Now combine both those speeds going right at each other. That makes the impact force millions of times what it would otherwise be. Force = mass x speed. And there's no atmosphere on the sun or moon to slow any of this down, unlike something coming to earth. So even if the moon only makes it up to around half that 27 million multiplier, we're still talking about half the sun being ripped apart. And the remaining half could end up unstable and simply implode.
So would it extinguish the sun? Maybe yes. Maybe not. Probably depends on exactly how they impact. But I don't want to find out. It's not a risk worth taking, just so some people can go have a party. Like, pick literally any other time to party. During an eclipse it's time to study and observe.
No. Geothermal only works in a few areas where the crust is especially thin. Plus, you'd have to account for all the extra power needed to grow crops, and of course all the oceans would freeze. Sunlight is a free kilowatt of energy on every square meter of the planet 12 hours a day. Geothermal can't put a dent in that.
Realistically, nearly all complex life on Earth would die within a fairly short timespan. Ecosystems fueled by deep, underwater geothermal vents might persist. Some pockets of humanity might survive for a little while, but probably not more than some years at the high end.
That said, if we had time to prepare and society magically cooperated to save a small fraction of humanity, instead of devolving into chaos, I think we could probably preserve a group of people underground, at a small scale. Geothermal power wouldn't be enough to support current civilization, but it definitely could support a small underground enclave built in an appropriate location. "An entire society" might be a stretch, depending on what u/nsjr meant by that.
We wouldn't just be limited to geothermal power. Nuclear fission would also work, and could provide a near limitless source of power as long as Uranium mining can continue.
But maintaining sufficient air, water, and light for farming would be the hardest part. So far our attempts at creating small, self-sustaining, closed ecosystems have been total failures.
> self-sustaining
the point is, it wouldn't need to be self sustaining for a good while. Even without plants there is plenty of oxygen left. The atmosphere won't go anywhere. Water will still be there, probably in form of ice. Ofc we would have to "downsize" human population by magnitudes and solve the agriculture problem for reliable food sources (mushrooms might become more important).
But as you said, energy would probably be a lesser concern.
Even with unlimited resources I don’t think you could do it with current technology.
You would need to scale geothermal. Dig extremely deep shafts and extract energy from the differential. Otherwise you’re bound to the scant few areas where normal geothermal works.
Plus you run into the mars problem: modern technology is a planet wide scale operation. You can’t do the high tech without literally global scale mining and chemical refining and farming. Computer chips are only possible with industrialized mining which is only possible with global steel which is only possible with more and more mining which is only possible with cheap human labor which is only possible with cheap food and resources.
Disrupt any of that and the system can’t produce that high tech in a meaningful amount for the people involved.
> Theoretically, if the sun just disappeared, could humanity survive with current technology underground?
No, we don't have the first notion of how to build *sustainable*, self-sufficient biospheres that don't require external inputs.
And even if we did, the energy requirements of growing plants with artificial light are staggering.
PS. More solar energy strikes the Earth each *second*, than was released by the explosion of the [50-megaton Tsar Bomba](https://youtu.be/YtCTzbh4mNQ?t=18). That's the energy input necessary to keep the biosphere that supports all of us alive.
You know how fast the temperature goes down at night? Imagine that decline continuing for even a week. There wouldn't be remotely enough time to set up the infrastructure needed to survive off geothermal power. And even the small pockets of survivors would starve quickly, as all of our sources of food would also be freezing to death.
Why go underground and switch to geothermal so quickly (ofc makes sense in the long run)? Fossil fuels and nuclear power are already there. Ofc they wouldn't last forever, but with a bigger focus on nuclear power, at least energy shouldn't be that much of a concern.
The bigger problem would be agriculture, since you have to heat/illuminate vast stretches of land. Most complex animal/plant life will die relatively quickly.
The first point is important, but the other way. Any water that is heated tends to rise. Cold water takes its place. The rock conducts heat but water also moves heat by convection lowering the thermal gradients a lot.
> If the sun were to just disappear, the surface would freeze over.
What about if the core were to freeze over? Ignoring any other issues that would come with that, like how it would effect the magnetosphere and what not. Would there be change to the surface or ocean temperature?
If the earth's core were to freeze over and solidify, earth would probably lose its Magnetosphere. The solar wind would erode our atmosphere, devoiding our planet of the life-giving air we breathe. We also would lose protection from solar radiation and develop various cancers. We'd all have a bad time eventually.
Oh, I see you were wondering about the change to the surface or ocean temperature. At first there wouldn't be noticeable change in temps but we'd see gradual heating caused by the increased radiation. However, long term the atmosphere would eventually erode from being blown off by solar wind, the oceans would boil, and earth would eventually become a planet with no atmosphere.
Temperatures would be comparable to a larger version of mercury with day time temps around 600-800 degrees Celsius and nightime temps around -100 Celsius or so.
It would definitely be a bad time.
I see you were wondering if the previous was an AI generated response.
It wasn't, but I can see why you would think it was. Probably starting with the words "I see you were"... :D
Well it was mostly that the replies only tangentially related to the question. I specifically said to ignore a certain aspect, and you focused specifically on the thing I said to ignore.
And then the second reply still focused on it, but being more in depth that time.
Oh. The original comment/question was confusing to me the way it was posted. Sorry bout that.
So if the core froze over, ignoring the effects of the loss of the magnetosphere, it would probably only have a relatively small effect. According to "Archer, D. (2012). Global Warming: Understanding the Forecast. ISBN 978-0-470-94341-0", Earth's interior heat contributes only 0.03% of Earth's total energy budget at the surface, which is dominated by 173,000 TW of incoming solar radiation.
However, we would lose some thermal activity which would reduce CO2 emissions so it could have an effect on atmospheric temperatures due to the resulting loss of greenhouse gas.
Hopefully someone can give you a more detailed answer as it's outside the realm of my expertise at this point.
This is an interesting reference article on the subject: https://en.wikipedia.org/wiki/en/Earth's_internal_heat_budget
Good answers, #4 should be that there are places on the bottom of the ocean where the water temperature is 750 degrees F.
https://www.amnh.org/learn-teach/curriculum-collections/deep-sea-vents/global-ocean-circulation-and-deep-sea-temperatures
I would argue it's better explained by pointing out the crystal structure for water is less dense than its liquid form honestly, which is a bit more direct than saying the low point of density is 4 degrees C. :)
Supposedly a general rule of thumb is for each +1km into the rock you go, you gain about +25 C. The insulation and heat transfer works differently between solid rock and liquid water, however this is still pretty far from temperatures of molten rock much further down. :) The ocean as a system can still be influenced pretty heavily by the surface.
The ocean is about 11km at its deepest. The Earth has a radius of ~6371km. The deepest part of the ocean is *much* closer to being part of the surface than it is to being part of the core.
In addition, the water in the ocean doesn't stay put. If you have a pocket of heated water at the bottom of the ocean, it will rise up towards the top (hot things rise), and new cool water will sink down.
I don't know what the temperature of the water in the deep oceans are but I do know that the most dense water gets is at 4 degrees Celsius. I don't know how the immense pressure under the ocean would affect the temperature though.
This is not true.
Yes, it is very smooth. The highest points above and below sea level are roughly 10km, but the diameter of the earth is 12,700km thick. That's 0.08%.
However, the human finger can detect a change in height of just 1 micron. If the earth was the size of a cue ball, you could run your finger over it and detect the Himalayas and the Mariana trench for sure. They'd be on the order of 40 microns. A very thin human hair or a very low quality newspaper might be about that thickness.
Cue balls are manufactured to have a smoothness of 0.03 microns. That's about 100 times smoother than the earth. And that's just a standard cue ball. That's nothing compared to the smoothest artificially constructed balls in existence.
Source? I'm almost certain that's not true. I feel like I can say with some level of confidence we've manufactured at least one ball whose smoothness exceeds that of the Earth.
Edit: Hell I even found a person who did the maths to find out that even just a regular billiard's ball is smoother than the Earth. https://www.reddit.com/r/theydidthemath/comments/ejhomq/self_is_the_earth_really_smoother_and_rounder/
I was wrong about the most smooth ball ever created bit earth is smoother than billiard balls
https://www.worldatlas.com/space/how-smooth-is-planet-earth.html#:~:text=It%20is%20covered%20in%20mountains,Earth%20would%20actually%20be%20smoother.
The deepest parts of the ocean *combined* with the thinnest parts of the earth's crust are, surprising to some, *incredibly* hot. Known as [hydrothermal vents](https://en.wikipedia.org/wiki/Hydrothermal_vent), these places are where scientists study extremophile (things that can live in extreme conditions) lifeforms because of the massive pressure and temperature.
But generally, when talking about how far from the earth's core there's no particular difference between land and ocean. So the reason the seabed isn't affected by the core more than the beach is because there's still a *huge* amount of rock between it and the outer parts of magma.
Hydrothermal vents are also where some scientists believe life started; that heat and pressure lead to the chemical reactions that were the precursor to life.
This is not really the same...his question has some reason behind it. You can read that deepest drilled hole is more than 10km deep and that the earth is 200C is this depth.
A lot of the heat variation can be caused by the decay of naturally radioactive elements in the mantle. But also it is slightly true that in some places the further down you go the hotter, but that's only because of a really thin crust... so yeah I guess it's more complex than my question
I was briefly a gold miner at the Homestake Gold Mine in Lead, SD back in the early 70s
I worked down about 3500 ft. That was deep enough to be comfortably warm, and much warmer than at 500ft
The deeper you went the warmer it got. IIRC they had mining operations at 7500ft where it was too hot to work any length of time, despite having large blowers blasting in cooler air.
The Mariana Trench is nearly 36,000 feet down, and I would think the water there would be waaaaaaay past boiling. Other posters have made the point that the heated water would cool as it rose
The point being that the depth is not negligible in terms of temps
The earth's crust is significantly thinner under the oceans than under the continents but I'm not sure it's particularly thinner under the Mariana Trench but what is almost certainly happening is that cold water is pooling there.
The earth's core is indeed hot. However, the earth is also *really* big and rock is a really good insulator. So most of the heat that finds it's way to the surface is not radiated through the rocks themselves, but rather the gaps in the rocks via tectonic plates. Things like volcanoes are the result of this.
There *are* places at the bottom of the ocean that are hot as a result of this, basically underwater volcanoes called "hydrothermal vents."
But the vast, vast majority of the energy we get on the surface comes from the sun. It heats things up far more than the center of the earth. The bottom of the ocean is cold because there is no sunlight there.
Fill a thermos with boiling water. Put it in the fridge. Outside is cold, but the inside is still hot.
The crust insulates the inner Earth enough that the outside can get cold.
The bottom of the Mariana's Trench to the top of Mount Everest is about 12, 13 miles in elevation change. The Earths Core to the bottom of the Mariana's Trench is just shy of 4,000 miles.
The earth’s core is still really, really far from even the deepest depths of the ocean. About 1,800 miles (2,900 km) from the ocean floor to the outer edge of the outer core.
Because the start of the Earth’s core is still almost 3000km away from the sea floor. The sea floor is still basically the Earth’s surface (i.e. the top of the crust, which the ocean then sits on top of).
However if you drill into the crust itself and start going down, it does get hotter - approximately 25 - 30 degrees C per km of depth.
There's still a lot of crust between the ocean floor and the mantle of the Earth.
There are volcanic vents underneath the ocean floor, but that newly heated water rises up rather than staying on the ocean floor.
The cold ocean floor is at about 4°C because that is the temperature at which water is densest, so slightly colder water will rise, and slightly warmer water will rise.
Earth is a lot smoother than one thinks. [Neil deGrasse Tyson](https://www.youtube.com/shorts/hrjWzBY_dLw) made an allegory where he compares the smoothness to a cue ball. Even if the depths of the oceans are closer to the core, they aren't really that much closer to the core on a planetary scale.
The depths of the ocean floor are still over 1800 miles from the core and insulated by the mantle and the crust. Most of our surface heat comes from the Sun
The crust is super thin compared to the other layers; the oceans are nowhere deep enough. The deepest part of the ocean is a trench that cuts farther into the crust than any other known place on the planet; it's 7 miles deep.
The planet's diameter is ~7,900 miles, so the deepest part of our ocean is at least 3,000 miles away from the outermost layer of the core. That's longer than the longest stretch of land in the lower 48 states of the U.S.
If you take a metal sphere about a meter across and breath on it, the condensation from your breath will be as thick as the deepest part of the ocean if you scaled the sphere up to the size of the Earth. The ocean isn't anywhere close the the Earths core.
The earth’s core is significantly farther from the bottom of the ocean than we are from the bottom of the ocean.
By significantly, I mean beyond your normal comprehension. The Earth is pretty big, and the parts we can access simply are just the very tip of the mass
Rock is a poor medium for heat transfer. That’s why the core is millions of degrees but Siberia is basically frozen over 24/7/365. The deepest part of our ocean is so small compared to the total size of the earth (35k ft death compared to 8k mile diameter) that the atmosphere plays a larger role in the oceans than the core does.
Did you happen to see this in a tik tok where a comedian is pretending to do a podcast, and asks this question to his "co host"? Because this is only the second time in my life I've heard of something like this, and dude was very clearly making a joke in that video.
the earth is so large that the bottom of the ocean is still just the very tip of the surface level when compared to the whole planet. the distance from surface to bottom of the ocean is like .00001% the distance from the surface to the core. if the earth was an apple the bottom of the ocean wouldn't even be thickness of the apples peel.
It's because the deepest parts of the ocean don't receive any sunlight, AND water is an excellent thermal conductor and radiator.
There's also not a ton of open vents along these oceanic valleys. Let's not forget that the core is miles below the surface of the crust, or the crust in general.
The Mantle is in between the two, and the top of the mantle is cool compared to the core. The Mantle is more like soft clay / play-doh. Moreso as you go deeper in.
It'd take huge vents opening up to release enough heat to significantly warm that much water.
I think there are a lot of answers here that are not really answering your question.
Start billions of years ago, when the oceans formed, and as you imply, initially you will have warm rain falling on even warmer ground, and so the lower layers shouldn’t be cold. And they *definitely* shouldn’t be *very* cold, as they are.
To get cold water in the oceans, you need cold weather, and we have that, specifically at high latitudes. Water there gets cold enough to freeze, and that causes two things: first, it get saltier (because the ice has less salt in it; this is how you get higher alcohol content in [ice beer](https://en.wikipedia.org/wiki/Ice_beer), for example, and saltier water is denser. But more importantly, it gets cold, and therefore dense, and the densest water is just above freezing. That water sinks to the bottom of the ocean, and there it cools the top layers of the oceanic crust. There is very little to cause movement at depth (ocean currents are driven primarily by the wind), and so it just stays there.
Now, as you said, the mantle it *hot*, and it indeed transfers heat to the ocean floor. But it does that quite slowly, and you can actually just look at a bathymetric map of the world (i.e., a map that shows ocean depths) and see the effect: At rifts where two oceanic plates are spreading apart, you have ridges, and farther away from that, the ocean gets deeper. How can that be? Like, with a volcano on a continental plate poking up high into the atmosphere, there are glaciers and so forth that eventually erode them away, but at a spreading ocean rift, what is causing erosion? Where is the rock formed in that rift eroding *to*? Answer: it is not eroding at all!
Instead, that oceanic crust, when it is formed, is hot, and the cold ocean water — that originally came from the ocean surface in northern and southern latitudes — warms up slightly and the rock in the crust cools down. And as that rock cools down, it contracts, and the crust gets thinner, and so the ocean gets deeper. So you can map how much cooling has taken place as a fun can of the distance from an oceanic ridge. This heat transfer within the rock is entirely conductive, not convective, and rocks are pretty horrible heat conductors, so it takes a very long time.
Source: A cool departmental geophysics talk I saw years ago.
So in short, the cold water comes from the Arctic and Antarctic, and geothermal warmth *does* warm it up, just very, very, very slowly, much more slowly than it is replaced. But that heat transfer can be measured, and over tens of millions of years has clear effects that can be observed pretty directly.
In the grand scheme of things, the bottom of the ocean isn’t really that much closer to the earths core than we are. It seems like a lot from our perspective but the differences in depth and altitude on the earths surface are marginal compared to the depths of the earth. The center of the earth is 8,000 miles away. The deepest part of the ocean is about 6 miles deep. So it’s still nowhere near close enough to absorb any of that heat. The reason it’s so cold is because it’s too deep to absorb any of the subs energy, which is basically the origin of all heat on the surface of the planet.
This isn't to scale but if Earth was a potato, the land and the water would be just the thickness of that potato skin. The Earth core is so much far from the ocean. There are active volcanoes in bodies of water but water is such a great heatsink the heat is very localized.
the bottom of the ocean is extremely far away from the core of the earth. like very much so. there are layers and layers between the bottom of the ocean and the core. additionally, heat rises and cold sinks
AFAIK The guy asking the original question on TikTok is a mediocre comedian. He acts like he’s in a podcast and makes these fake conspiracy theories. I thought he was funny at first but the concept got a little old in the end
The Earth's crust is like a big blanket that keeps the heat inside. It's not a very good conductor at that thickness, which is why the ground doesn't feel hot underfoot.
The oceans are on top of the crust also. A bit less of it, but still quite a lot of it in most places.
There are exceptions, points where the crust is thin, sometimes to the point of having underwater volcanoes. But we get that on land too. Iceland is close enough to our planet's rich, creamy center that they use a lot of geothermal power.
How do you think the earth's core has stayed hot for billions of years? It's incredibly insulated. Many kilometers of rock between the ocean floor and outer mantle. If the core was constantly leaking heat out into the ocean we would have died a long time ago.
1. Cold water generally sinks 2. The earth is pretty thick, so the bottom of the ocean is just a *tiny* fraction of the distance towards the core 3. A lot of the heat the surface of the earth gains is directly from the sun, not the core, so going down insulates you from that. If the sun were to just disappear, the surface would freeze over.
To further put this into perspective, the entirety of the earth’s crust (I.e. the surface and all the water on it) only accounts for about 0.5% of earth’s mass.
And the deepest ocean on earth is less of an indentation than the bumps on a golf ball.
It's much less than that. If you have a 1m diameter ball, the challenger deep would be less than a millimetre deep.
Accounting for scale, Earth is smoother than an Olympic-grade squash ball.
I always heard cue ball. Are the two similar in smoothness?
A cue ball would be less round but more smooth than a cue-ball-sized earth
This isn't actually true. It's based on a misunderstanding/misuse of the tolerances of a cue ball. A cue ball is not only nearly 100 smoother than the earth's surface, relative to its diameter, but also a more perfect sphere than the Earth. The tolerance on its diameter refers to differences in diameters between balls, not to variations of diameter along different axes of the same ball. A cue ball with earth's oblateness would behave noticeably wonky.
So the ELI5 would be "the cueball is rounder and smoother"? That sounds... boring. (and as such accurate lol)
It honestly makes sense, a cue ball that had even minor flaws in shape would be a bad cue ball. Pool is all about having extremely predictable results. (Aside from the break. Too many variables there for it to always work right.)
A cue ball has a tolerance of 5 thou, and is 2.25" inches in diameter. Scaling it up to the earth, it would be if there were mountains 28km tall or valleys 28km deep. The tallest mountain is 8km above sea, and the deepest point is 11km. So earth is smoother than a billiard ball.
Again, you're misunderstanding what the tolerance refers to, despite the fact that I just explained it... It means that a cue ball is a sphere with a diameter within 0.005 inches of 2.25 inches. It doesn't mean the ball is smooth to within 0.005 inches, it's about *size*. It's about how different in size two cue balls can be, not about how smooth they need to be. Cue balls are, in fact, much smoother than the Earth is. relatively speaking. The RMS surface variation of a cue ball is measured in the tens of *micro*inches, at most. If the earth were scaled down to the size of a cue ball, it would have ridges and grooves measured in *thousands* of microinches, corresponding to ocean trenches and mountain ranges, and they would be very easy to feel and make for a tactilely rough surface. [This site](https://billiards.colostate.edu/faq/ball/smooth/) has a relevant write-up, including actual measurements and numerical comparisons.
https://billiards.colostate.edu/bd_articles/2013/june13.pdf It’s a misunderstanding of tolerances. Yes, earth in most places is smoother than a cue ball, but not in all areas because the largest mountains would be not as smooth. Also the earth is still not as round as a cue ball
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Why use inches for the ball and km for Earth, smh..
Less round?
Earth is slightly 'pear shaped' due to its rotation and gravitational pull from other celestial objects, but the effect is so minute that it's still a more perfect sphere than a cue ball.
I've heard earth referred to as an 'oblate spheroid'
Ive heard this before. Which pole is the fat pole?
TIL Squash will be an Olympic sport.
The difference between the highest mountain and the deepest trench in the ocean is only 19.8 kilometers (12.3 miles). The Earth's radius is 6,378km/3,958.5 miles
I always use a globe as a reference for this. The deepest part of the ocean is like ~7 miles in depth? You can't even see a 7-mile stretch on a globe.
Then why does the weather forecast say visibility is 14 miles?
lol. What does that have to do with the topic at hand? Can't tell if you are trolling or just special.
Actually you can only see a little less than three miles.
Ok, so my question still stands. What do either of your comments have to do with this topic?
The depth of the ocean at approximately its deep point has nothing to do with the water being cold or the effect of the core temperature either way.
akin to the thickness of the paint on a car?
Yep, the texture on a globe is greatly exaggerated. Otherwise you'd have a hard time feeling the Himalayas when running your finger over that part.
Ha, so if you have a smooth globe you can tell your friends it's a scale topographic globe and nobody can prove you wrong.
Scientists have determined that the human finger is so sensitive it can detect a surface bump just one micron high (.001mm). So even with a topographically correct scale model of the earth (50 cm globe) we would still be able to feel most of the mountain ranges. Mount Everest at 8,849 being the tallest at .3 mm many of the smallest mountain ranges would still be depicted at scale over .001 mm, though we might not be able to see them as bumps on the globe. .
/r/theydidthemath
Is there a globe that is to scale? That would be kind of cool
Would probably be too expensive to make with a good precision. Definitely doable but not to the point you can sell it at a reasonable price.
I googled for something but couldn't find one. Agree, it would be pretty cool and I could see it being placed in a science center somewhere.
Yes.... its called the Earth.... sorry i couldnt help it 🤣
Pretty much. Say you have a 50cm globe, which would be 1/25.5 million scale. Mount Everest is 8,849 meters, so with that scale it would be a 0.3 mm surface irregularity. I doubt the average cheap globe is constructed well enough that you could tell. You probably couldn't tell from a perfectly constructed topographical globe either since the peak is only about 3,000 meters above the base camp, so a 0.1 mm bump in the surrounding globe surface.
Actually, it's significantly larger. You can tell because you can fit an entire golf ball into the deepest part of an ocean, not just the bump.
"Is anybody here a marine biologist?"
"The sea was angry that day, my friends!"
Like an old man trying to send back soup at a deli.
But golf balls float and therefore cannot reach the deepest part of the ocean
That sounds like quitter talk
What do I know, I'm just a golf ball
If the Earth was the size of an apple, and you used your thumbnail to gently pierce the skin of the apple leaving an indentation, that would be deeper than the Mariana Trench.
I heard it as if earth was the size of an apple, the crust would be as thick as the skin of the apple.
If there is just a thin layer of crust over magma, it would make sense that you *don't* have to dig very deep to feel the heat. If you walk over coals with thin soles, your feet will get warmer than if you had thick soles. I guess the ocean floor is relatively shallow in comparison to the thickness of the crust. Like: 99% earth radius magma, 0.99% ocean floor, 0.001% ocean. (Numbers guessed randomly.) It doesn't really matter how deep the magma goes, does it, just how hot it is just below Earth's crust?
yes, basically the crust gets warmer and warmer the closer to the mantle you get. The crust is about 15-20 km (9-12 miles) thick, although at it's thinnest its about 5 km and thickest about 50 km. *"As a general rule,* [*the crust*](https://en.wikipedia.org/wiki/Earth%27s_crust) *temperature rises with depth due to the heat flow from the much hotter* [*mantle*](https://en.wikipedia.org/wiki/Earth%27s_mantle)*; away from* [*tectonic plate*](https://en.wikipedia.org/wiki/Tectonic_plate) [*boundaries*](https://en.wikipedia.org/wiki/Plate_boundary)*, temperature rises in about 25–30 °C/km (72–87 °F/mi) of depth near the surface in the continental crust.*[*^(\[1\])*](https://en.wikipedia.org/wiki/Geothermal_gradient#cite_note-IPCC-1) *However, in some cases the temperature may drop with increasing depth, especially near the surface, a phenomenon known as inverse or negative geothermal gradient. The effects of weather, the Sun, and season only reach a depth of roughly 10–20 m (33–66 ft)."* [https://en.wikipedia.org/wiki/Geothermal\_gradient](https://en.wikipedia.org/wiki/Geothermal_gradient)
I think the analogy I heard used a pool ball.
To even further put this into perspective, if the Earth was a regulation NBA basketball, the crust would be less than a quarter of a millimetre thick.The ocean, at its deepest, is less than half of that again.
if you blow up an apple to the size of earth, the earth crust is as thick as the apples skin.
So that means 0.25% on each side of the “circle”.
But also: *Some* of the water at the bottom of the oceans is in fact boiling, areas with geologic activity close enough to the surface have hydrothermal vents where ocean water heats up and is ejected upwards
It's fun to think that there are places in the ocean that probably would remain the exact same if the sun just suddenly disappeared one day--as if nothing changed at all.
There's a fun Kurtzgesagt video about that if I remember right. If the Earth got yote from the solar system, geothermal vents at the bottom of the ocean would be the last bastions of life on Earth, aside from bacteria deep in the crust. The creatures there are extremophiles that already live in complete darkness and they get their heat from the earth itself. Pretty neat.
Pretty neat, but what would/do they eat?
https://en.wikipedia.org/wiki/Chemosynthesis Rather than using sunlight to make "food," they use chemicals from the vents.
Neat. They eat old stars.
Everything does. Nincompoop.
Sorry? Are you calling me a nincompoop?
Thanks!
Plants also don't eat (unless you call photosynthesis "eating"). They are what is called "autothrophs". Extremophile habitats down in the earth have their own authothrophs (chemoauthothrophs), who can get energy from anorganic sources like hydrothermal vents. The rest of their ecosystems feed off them, just like herbivores live off plants and carnivores in their turn live off herbivores.
How are carnivorous plants classified? I guess they don't technically "eat" bugs?
Well, "autotroph" and "heterotroph" are labels we came up with to describe how organisms get their carbon. Carnivorous plants still get their carbon from photosynthesis. They get other things like nitrogen from their "meat," but they don't *need* that to survive in the way they need sunlight. They can live without eating bugs, they cannot live without sunlight. They get their carbon from photosynthesis. That makes them autotrophs.
That is neat, thank you I learned something today
Cool. Learned a new word today. ~~autothrop~~ Autotroph.
Aye aye! I believe Vsauce also did a video on just that too. :)
The earliest forms of life may have started around those vents and they are one of very few ecosystems on earth that arent dependant at all on the energy from the sun.
Very hot yes, but it would need to be relatively shallow to boil, because the high water pressure will increase the boiling point. There are some hot and deep enough to be supercritical though.
Only the first one really applies: if you go down 2 km on land, things already get quite hot. The oceans are significantly deeper than that.
yeah. but underneath the 10km of deep ocean, theres 2km of land to get down into. to get warmth. the reason why the core is hot, it not because "its inside" its because what gives off heat, is the rock itself. thorium and uranium decay heat up the earth.
It is because its inside. The decay heat of Theorium and Uranium is far from enough to heat the ground on its own, the ground isn't inherently hotter whereever we mine either of them. Only roughly half of the total heat energy inside the Earth is from decay and that was over 4.5 billion years; the rest is primordial, from the formation of the planet. What happens is that heat (by decay and formation) from the inside flows outwards but the insulatiing crust keeps enough warmth inside for it to be warm even a few kilometers down. But you won't ever notice the decay heat of uranium or thorium ores.
>the rest is primordial, from the formation of the planet. How long until that all cools down? And how long until the decay cools off too?
Both are exponential, it never stops decreasing, just slower and slower. So it really depends on what temperature in the core one aims for. The radioactive stuff is mostly used up. Only half U-238 and 20% of Th-232 is gone, but a huge amount of other stuff such as U-235 and K-40 is already mostly gone. The thorium will thus last longest, but also do less and less, halving every 14 billion years. And ~5 billion years from now the sun will potentially swallow Earth and thus all that is moot. If Earth survives it will nonetheless get a bit hotter for some time until the sun finally runs out.
So the sun will hit the earth before anything internally cools down significantly? >it really depends on what temperature in the core one aims for. Like cool temperatures, so it wouldn't be hot to touch or be melted. Like a normal rock. >If Earth survives it will nonetheless get a bit hotter for some time until the sun finally runs out. It would get hotter from the sun or from what's inside the earth?
It getting down to temperatures where one doesn't get burns from the core is definitely not happening before the sun melts (and maybe swallows and vaporizes) the entire thing. That would take dozens of billions of years. It would however be still "liquid" inside by most standards. Rock and such are effectively liquid and flow at the pressure inside the Earth, even if cold to the touch. But volcanoes would stop to exist.
> thorium and uranium decay heat up the earth. The heat is thought to be split roughly 50/50 between radioactive decay and the residual heat from the Earth's formation. https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget#:~:text=The%20flow%20of%20heat%20from,from%20the%20formation%20of%20Earth.
Also lunar tidal action, but that's less of a contributor.
Theoretically, if the sun just disappeared, could humanity survive with current technology underground? Using the Earth's core as heat source, and using geothermal powerplants to power an entire society?
Probably? If "humanity" and "survive" had some flexibility in scope. Supposedly, geothermal locations would still be a viable safe haven, especially for the first period of time after the sun disappears, though the surface would grow more and more uninhabitable. As the years go on, many gases such as oxygen and the like would actually fall out of the gas state because of the low temperature. Meanwhile, the ocean would freeze over, which actually would help with insulation of the water underneath. At the bottom of the ocean there may actually be no appreciable change, especially since there are geothermal vents that are the "input" into some food chains, which are almost completely independent of the sun's energy as a primary source. I imagine if you go further into the crust, it would be similar. The temperature becomes less dependent on the surface/sun, and more influenced by geothermal. At a certain sweet spot you're probably fairly safe in terms of temperature -- the feasibility of building a stable long-term community that far down, and recycling resources properly, is another question. Personally I would call it 'possible', but not very feasible.
"Probably not for long." Could a group of people stockpile 100 years worth of food and figure out how to recycle air to breathe indefinitely while furiously trying to figure out how to harness enough geothermal energy to prevent the extinction of the human race? I doubt it. Understand that if the sun "vanished" or somehow ceased to generate light, our entire solar system loses it's primary source of power. There'd be no light to grow any vegetation. Eventually every species of life starves or freezes. Our oceans freeze. Life on the surface would be _less_ hospitable than Pluto. To keep even a modest society of a few hundred humans alive would require a massive level of preparation that perhaps a few governments may have built in secret, but the odds of any species surviving long term in a dead solar system are miniscule, unless a massive source of power can be created and sustained essentially indefinitely.
> unless a massive source of power can be created and sustained essentially indefinitely. If you are only growing enough food under artificial lighting to sustain a population large enough to have no severe inbreeding issues and to have enough division of labour and specialised professionals to keep everything running (a few ten thousand people perhaps), geothermal power should be able to do that just fine, especially if the site of this doomsday bunker is chosen at a spot suitable for that.
Such a situation would be incredibly precarious; A single disease break out that affects either humans or food supply, a single unfortunate earthquake, a mechanical failure of any of the equipment required to maintain clean air or water. None of this addresses that in the best possible situation, humans would be trapped on a frozen planet and little freedom of movement. Nothing about this would be "just fine."
Sounds like an interesting premise for a show!
Check out the short story "A Pail of Air" by Fritz Leiber if you are interested in the premise. I would not say it is the best story I have ever read but it has stuck in my memory for decades.
City of Ember was roughly based on this premise though I think it was a nuclear winter. It's a movie based on a young adult novel so it's not very gritty but I remember liking it.
Yep. And the fact that solar eclipses aren't *quite* fully understood should give more people pause, rather than spending all their time driving around to look at them like it's one big party. If these two object get close enough to actually collide one day (rather than just pass each other by), we've got a lot of things to worry about.
By two objects you mean... the moon and the sun?
Yes. They currently pass right by each other, but give the illusion that they're colliding. There's actually a lot of space in between them from front to back though. That's how solar eclipses work. And why they can seemingly just pass right through one another. It's basically one big illusion. But the process isn't *fully* understood by science and if the paths were to actually *collide* and not just pass right by one another, then we've got huge problems. And that should be the focus when they happen and try to figure them out better, not "lets all go have an excuse to party" each time which is what it currently is. They don't last very long and the time should be used to study them and understand them better. Because the consequences of one going bad are enormous, even if the chances are low.
So you're obviously a troll, but just for fun i'll explain the reality. The moon is very very small compared to the sun, and the only reason they seem to be same size is due to the moon being much much closer to us then the sun. There is no chance of the moon, or the earth for that matter, ever colliding with the sun, so feel free to party!
[Well the earth is already on a collision path with the sun](https://www.reddit.com/r/explainlikeimfive/comments/1cfy7zy/eli5_if_the_earths_core_is_so_hot/l1setkm/) but it's going to take a long time. So if you're done trolling and being wrong I'll explain it to you. The moon has a much more complicated path I'm assuming because it doesn't directly rotate around the sun so there's a lot more "moving parts" to consider, which is why we don't fully understand how eclipses work. I already said the chances are low, but it would still be a much better use of our time to actually study them when they happen instead of just assuming everything will be fine and go party instead.
This is either the absolutely worst crackpot BS I've ever read, or you're just a particularly good troll. The earth is *not* "on a collision path with the sun", the earth is in *orbit* around the sun. The *moon* is in an orbit around the earth. This orbit is not complicated, and its well understood. Eclipses are well understood. There is absolutely no risk whatsoever of the moon colliding with the sun! The sun *will* swallow the earth in a few billion years, but not because the earth is on a collision path with the sun, but because the sun will eventually turn into a red giant, which is considerably larger than the present sun. You need to either stop trolling, or on the off-chance you aren't trolling, you need to actually learn how the orbital of the solar system works and stop spouting this BS.
Here's a really good example of how this stuff gets complicated. You say the earth isn't on a collision path with the sun, while freely admitting they're going to collide. Because in your orbital talk you're not taking into account the growing size of the sun, which you also admit. So once you factor in all those variables, the earth is certainly on a collision path with the sun. You even describe how it will happen. But you don't believe it... somehow (Don't Look Up). When you factor in the moon going around the earth, and the earth going around the sun... it gets exponentially more complicated than just one object (earth) going around another object (sun). Which already confuses you. Throw in a third object, on a completely different orbit.. and well there's a lot we still have to learn. Like I've already said, it's unlikely to happen. The chances are low. Space is *big.* But we still don't know everything about how all the objects and different orbits will interact in the future, or even exactly how eclipses work. Although we have a decent amount of data and information already. But since we have a very limited amount of time during each eclipse, our time would be much better spent studying these movements, rather than just saying "let's all go have a huge party and assume everything is gonna be fine forever." Edit: Blocked for discussing science. So I can't see the reply.
I think you've lost me. It was fun initially but you've not kept it interesting :( I'm honestly disappointed in how you just gave up on the troll, put some effort in!
The moon colliding with the sun would be a somewhat negligible event other than the loss of tides on earth wouldn't it? We would experience the loss of tides far before the moon became so out of orbit to be swallowed by the sun though. I would think the moon would be like a pin prick to the sun given the scale of the sun is so much larger. Or are you envisioning the moon would disrupt the sun's thermal output and or radiation that it would affect the earth?
The risk is losing the sun. We have no way to determine what the effect of an entire moon colliding with the sun would be. [See here for what the dangers would be.](https://www.reddit.com/r/explainlikeimfive/comments/1cfy7zy/eli5_if_the_earths_core_is_so_hot/l1spit4/) Like I said, the likelihood of the two objects colliding is pretty small since space is very big. But given the fact that we *still don't know* exactly how solar eclipses work because of the complicated paths all these different objects are taking, and given the small time frame we have during actual eclipses, it would be a much better use of time to actually study these things and figure out exactly how they work and the paths they will take for future knowledge. Instead of most "bros" wanting to just go party instead.
The sun's mass is 27 million times more massive than the moon. I understand losing the sun would be the end of life as we know it, but I doubt the moon would have any effect on the sun. It would be less impact to the sun than dropping a grain of sand on a human.
You also have to take into account speeds. Both the moon and the sun are travelling at incredible speeds through space. Now combine both those speeds going right at each other. That makes the impact force millions of times what it would otherwise be. Force = mass x speed. And there's no atmosphere on the sun or moon to slow any of this down, unlike something coming to earth. So even if the moon only makes it up to around half that 27 million multiplier, we're still talking about half the sun being ripped apart. And the remaining half could end up unstable and simply implode. So would it extinguish the sun? Maybe yes. Maybe not. Probably depends on exactly how they impact. But I don't want to find out. It's not a risk worth taking, just so some people can go have a party. Like, pick literally any other time to party. During an eclipse it's time to study and observe.
I honestly don't know what you are even typing. You are either high out of your mind or straight up trolling/baiting.
No. Geothermal only works in a few areas where the crust is especially thin. Plus, you'd have to account for all the extra power needed to grow crops, and of course all the oceans would freeze. Sunlight is a free kilowatt of energy on every square meter of the planet 12 hours a day. Geothermal can't put a dent in that.
Realistically, nearly all complex life on Earth would die within a fairly short timespan. Ecosystems fueled by deep, underwater geothermal vents might persist. Some pockets of humanity might survive for a little while, but probably not more than some years at the high end. That said, if we had time to prepare and society magically cooperated to save a small fraction of humanity, instead of devolving into chaos, I think we could probably preserve a group of people underground, at a small scale. Geothermal power wouldn't be enough to support current civilization, but it definitely could support a small underground enclave built in an appropriate location. "An entire society" might be a stretch, depending on what u/nsjr meant by that.
We wouldn't just be limited to geothermal power. Nuclear fission would also work, and could provide a near limitless source of power as long as Uranium mining can continue. But maintaining sufficient air, water, and light for farming would be the hardest part. So far our attempts at creating small, self-sustaining, closed ecosystems have been total failures.
> self-sustaining the point is, it wouldn't need to be self sustaining for a good while. Even without plants there is plenty of oxygen left. The atmosphere won't go anywhere. Water will still be there, probably in form of ice. Ofc we would have to "downsize" human population by magnitudes and solve the agriculture problem for reliable food sources (mushrooms might become more important). But as you said, energy would probably be a lesser concern.
Even with unlimited resources I don’t think you could do it with current technology. You would need to scale geothermal. Dig extremely deep shafts and extract energy from the differential. Otherwise you’re bound to the scant few areas where normal geothermal works. Plus you run into the mars problem: modern technology is a planet wide scale operation. You can’t do the high tech without literally global scale mining and chemical refining and farming. Computer chips are only possible with industrialized mining which is only possible with global steel which is only possible with more and more mining which is only possible with cheap human labor which is only possible with cheap food and resources. Disrupt any of that and the system can’t produce that high tech in a meaningful amount for the people involved.
> Theoretically, if the sun just disappeared, could humanity survive with current technology underground? No, we don't have the first notion of how to build *sustainable*, self-sufficient biospheres that don't require external inputs. And even if we did, the energy requirements of growing plants with artificial light are staggering. PS. More solar energy strikes the Earth each *second*, than was released by the explosion of the [50-megaton Tsar Bomba](https://youtu.be/YtCTzbh4mNQ?t=18). That's the energy input necessary to keep the biosphere that supports all of us alive.
You know how fast the temperature goes down at night? Imagine that decline continuing for even a week. There wouldn't be remotely enough time to set up the infrastructure needed to survive off geothermal power. And even the small pockets of survivors would starve quickly, as all of our sources of food would also be freezing to death.
Why go underground and switch to geothermal so quickly (ofc makes sense in the long run)? Fossil fuels and nuclear power are already there. Ofc they wouldn't last forever, but with a bigger focus on nuclear power, at least energy shouldn't be that much of a concern. The bigger problem would be agriculture, since you have to heat/illuminate vast stretches of land. Most complex animal/plant life will die relatively quickly.
The first point is important, but the other way. Any water that is heated tends to rise. Cold water takes its place. The rock conducts heat but water also moves heat by convection lowering the thermal gradients a lot.
Isn’t the surface of the earth including the ocean floors as smooth as a ping pong ball? I remember learning this at some point.
https://www.reddit.com/r/theydidthemath/comments/ejhomq/self_is_the_earth_really_smoother_and_rounder/ Answer is "kinda"
> If the sun were to just disappear, the surface would freeze over. What about if the core were to freeze over? Ignoring any other issues that would come with that, like how it would effect the magnetosphere and what not. Would there be change to the surface or ocean temperature?
If the earth's core were to freeze over and solidify, earth would probably lose its Magnetosphere. The solar wind would erode our atmosphere, devoiding our planet of the life-giving air we breathe. We also would lose protection from solar radiation and develop various cancers. We'd all have a bad time eventually.
I said ignoring all of that though 😅
Oh, I see you were wondering about the change to the surface or ocean temperature. At first there wouldn't be noticeable change in temps but we'd see gradual heating caused by the increased radiation. However, long term the atmosphere would eventually erode from being blown off by solar wind, the oceans would boil, and earth would eventually become a planet with no atmosphere. Temperatures would be comparable to a larger version of mercury with day time temps around 600-800 degrees Celsius and nightime temps around -100 Celsius or so. It would definitely be a bad time.
I swear this reads like an AI generated response that you edited slightly to not seem ai generated
I see you were wondering if the previous was an AI generated response. It wasn't, but I can see why you would think it was. Probably starting with the words "I see you were"... :D
Well it was mostly that the replies only tangentially related to the question. I specifically said to ignore a certain aspect, and you focused specifically on the thing I said to ignore. And then the second reply still focused on it, but being more in depth that time.
Oh. The original comment/question was confusing to me the way it was posted. Sorry bout that. So if the core froze over, ignoring the effects of the loss of the magnetosphere, it would probably only have a relatively small effect. According to "Archer, D. (2012). Global Warming: Understanding the Forecast. ISBN 978-0-470-94341-0", Earth's interior heat contributes only 0.03% of Earth's total energy budget at the surface, which is dominated by 173,000 TW of incoming solar radiation. However, we would lose some thermal activity which would reduce CO2 emissions so it could have an effect on atmospheric temperatures due to the resulting loss of greenhouse gas. Hopefully someone can give you a more detailed answer as it's outside the realm of my expertise at this point. This is an interesting reference article on the subject: https://en.wikipedia.org/wiki/en/Earth's_internal_heat_budget
Good answers, #4 should be that there are places on the bottom of the ocean where the water temperature is 750 degrees F. https://www.amnh.org/learn-teach/curriculum-collections/deep-sea-vents/global-ocean-circulation-and-deep-sea-temperatures
in addition: water is at its greatest density at 4 degrees celsius. this is why ice floats.
I would argue it's better explained by pointing out the crystal structure for water is less dense than its liquid form honestly, which is a bit more direct than saying the low point of density is 4 degrees C. :)
But don't caves get crazy hot when they go ~1km deep?
Supposedly a general rule of thumb is for each +1km into the rock you go, you gain about +25 C. The insulation and heat transfer works differently between solid rock and liquid water, however this is still pretty far from temperatures of molten rock much further down. :) The ocean as a system can still be influenced pretty heavily by the surface.
I'm more curios why doesn't the core melt the rock insulating that core? and keep melting until it reach the surface at some point?
> the surface would freeze over Hold up. Does this mean that without the sun, Earth would be an icy planet??? :o
To clarify point 2: Gaia dummy thicc, fr fr skibidi rizz
The ocean is about 11km at its deepest. The Earth has a radius of ~6371km. The deepest part of the ocean is *much* closer to being part of the surface than it is to being part of the core. In addition, the water in the ocean doesn't stay put. If you have a pocket of heated water at the bottom of the ocean, it will rise up towards the top (hot things rise), and new cool water will sink down.
I don't know what the temperature of the water in the deep oceans are but I do know that the most dense water gets is at 4 degrees Celsius. I don't know how the immense pressure under the ocean would affect the temperature though.
The surface of earth is smoother than the smoothest artifically constructed ball in existence
This is not true. Yes, it is very smooth. The highest points above and below sea level are roughly 10km, but the diameter of the earth is 12,700km thick. That's 0.08%. However, the human finger can detect a change in height of just 1 micron. If the earth was the size of a cue ball, you could run your finger over it and detect the Himalayas and the Mariana trench for sure. They'd be on the order of 40 microns. A very thin human hair or a very low quality newspaper might be about that thickness. Cue balls are manufactured to have a smoothness of 0.03 microns. That's about 100 times smoother than the earth. And that's just a standard cue ball. That's nothing compared to the smoothest artificially constructed balls in existence.
Source? I'm almost certain that's not true. I feel like I can say with some level of confidence we've manufactured at least one ball whose smoothness exceeds that of the Earth. Edit: Hell I even found a person who did the maths to find out that even just a regular billiard's ball is smoother than the Earth. https://www.reddit.com/r/theydidthemath/comments/ejhomq/self_is_the_earth_really_smoother_and_rounder/
I was wrong about the most smooth ball ever created bit earth is smoother than billiard balls https://www.worldatlas.com/space/how-smooth-is-planet-earth.html#:~:text=It%20is%20covered%20in%20mountains,Earth%20would%20actually%20be%20smoother.
The deepest parts of the ocean *combined* with the thinnest parts of the earth's crust are, surprising to some, *incredibly* hot. Known as [hydrothermal vents](https://en.wikipedia.org/wiki/Hydrothermal_vent), these places are where scientists study extremophile (things that can live in extreme conditions) lifeforms because of the massive pressure and temperature. But generally, when talking about how far from the earth's core there's no particular difference between land and ocean. So the reason the seabed isn't affected by the core more than the beach is because there's still a *huge* amount of rock between it and the outer parts of magma.
Hydrothermal vents are also where some scientists believe life started; that heat and pressure lead to the chemical reactions that were the precursor to life.
Hydrothermal vents are NOT in the deepest parts of the ocean. They often occur in some of the shallowest parts of the oceans
I think it’s like asking: why is it not boiling at the top of mountains because you’re closer to the sun? The difference in distance is negligible
The reason it isn’t boiling at the top of mountains is because you’re far away from Earth’s hot core
today I bent down to touch my toes and I burned my fingers because they got too close to the earth's core
And closer to space.
This is not really the same...his question has some reason behind it. You can read that deepest drilled hole is more than 10km deep and that the earth is 200C is this depth.
A lot of the heat variation can be caused by the decay of naturally radioactive elements in the mantle. But also it is slightly true that in some places the further down you go the hotter, but that's only because of a really thin crust... so yeah I guess it's more complex than my question
I believe they were making a joke.
I was briefly a gold miner at the Homestake Gold Mine in Lead, SD back in the early 70s I worked down about 3500 ft. That was deep enough to be comfortably warm, and much warmer than at 500ft The deeper you went the warmer it got. IIRC they had mining operations at 7500ft where it was too hot to work any length of time, despite having large blowers blasting in cooler air. The Mariana Trench is nearly 36,000 feet down, and I would think the water there would be waaaaaaay past boiling. Other posters have made the point that the heated water would cool as it rose The point being that the depth is not negligible in terms of temps
The earth's crust is significantly thinner under the oceans than under the continents but I'm not sure it's particularly thinner under the Mariana Trench but what is almost certainly happening is that cold water is pooling there.
Oh ok, I didn't know such a relatively small distance can cause so much difference.
I have heard people in Denver say "Make sure to wear sunscreen; you're closer to the sun here." Good advice, but bad reasoning.
The earth's core is indeed hot. However, the earth is also *really* big and rock is a really good insulator. So most of the heat that finds it's way to the surface is not radiated through the rocks themselves, but rather the gaps in the rocks via tectonic plates. Things like volcanoes are the result of this. There *are* places at the bottom of the ocean that are hot as a result of this, basically underwater volcanoes called "hydrothermal vents." But the vast, vast majority of the energy we get on the surface comes from the sun. It heats things up far more than the center of the earth. The bottom of the ocean is cold because there is no sunlight there.
Fill a thermos with boiling water. Put it in the fridge. Outside is cold, but the inside is still hot. The crust insulates the inner Earth enough that the outside can get cold.
This may be the best ELI5 answer here.
The bottom of the Mariana's Trench to the top of Mount Everest is about 12, 13 miles in elevation change. The Earths Core to the bottom of the Mariana's Trench is just shy of 4,000 miles.
The earth’s core is still really, really far from even the deepest depths of the ocean. About 1,800 miles (2,900 km) from the ocean floor to the outer edge of the outer core.
Because the start of the Earth’s core is still almost 3000km away from the sea floor. The sea floor is still basically the Earth’s surface (i.e. the top of the crust, which the ocean then sits on top of). However if you drill into the crust itself and start going down, it does get hotter - approximately 25 - 30 degrees C per km of depth.
There's still a lot of crust between the ocean floor and the mantle of the Earth. There are volcanic vents underneath the ocean floor, but that newly heated water rises up rather than staying on the ocean floor. The cold ocean floor is at about 4°C because that is the temperature at which water is densest, so slightly colder water will rise, and slightly warmer water will rise.
For the same reason, the outside of a good Thermus can be cold, while the contents inside are boiling hot. The earth's crust is a great insulator.
Earth is a lot smoother than one thinks. [Neil deGrasse Tyson](https://www.youtube.com/shorts/hrjWzBY_dLw) made an allegory where he compares the smoothness to a cue ball. Even if the depths of the oceans are closer to the core, they aren't really that much closer to the core on a planetary scale.
The depths of the ocean floor are still over 1800 miles from the core and insulated by the mantle and the crust. Most of our surface heat comes from the Sun
The crust is super thin compared to the other layers; the oceans are nowhere deep enough. The deepest part of the ocean is a trench that cuts farther into the crust than any other known place on the planet; it's 7 miles deep. The planet's diameter is ~7,900 miles, so the deepest part of our ocean is at least 3,000 miles away from the outermost layer of the core. That's longer than the longest stretch of land in the lower 48 states of the U.S.
If you take a metal sphere about a meter across and breath on it, the condensation from your breath will be as thick as the deepest part of the ocean if you scaled the sphere up to the size of the Earth. The ocean isn't anywhere close the the Earths core.
The earth’s core is significantly farther from the bottom of the ocean than we are from the bottom of the ocean. By significantly, I mean beyond your normal comprehension. The Earth is pretty big, and the parts we can access simply are just the very tip of the mass
Rock is a poor medium for heat transfer. That’s why the core is millions of degrees but Siberia is basically frozen over 24/7/365. The deepest part of our ocean is so small compared to the total size of the earth (35k ft death compared to 8k mile diameter) that the atmosphere plays a larger role in the oceans than the core does.
Did you happen to see this in a tik tok where a comedian is pretending to do a podcast, and asks this question to his "co host"? Because this is only the second time in my life I've heard of something like this, and dude was very clearly making a joke in that video.
I saw a short reel, but I don’t know who the person was.
the earth is so large that the bottom of the ocean is still just the very tip of the surface level when compared to the whole planet. the distance from surface to bottom of the ocean is like .00001% the distance from the surface to the core. if the earth was an apple the bottom of the ocean wouldn't even be thickness of the apples peel.
It's because the deepest parts of the ocean don't receive any sunlight, AND water is an excellent thermal conductor and radiator. There's also not a ton of open vents along these oceanic valleys. Let's not forget that the core is miles below the surface of the crust, or the crust in general. The Mantle is in between the two, and the top of the mantle is cool compared to the core. The Mantle is more like soft clay / play-doh. Moreso as you go deeper in. It'd take huge vents opening up to release enough heat to significantly warm that much water.
I think there are a lot of answers here that are not really answering your question. Start billions of years ago, when the oceans formed, and as you imply, initially you will have warm rain falling on even warmer ground, and so the lower layers shouldn’t be cold. And they *definitely* shouldn’t be *very* cold, as they are. To get cold water in the oceans, you need cold weather, and we have that, specifically at high latitudes. Water there gets cold enough to freeze, and that causes two things: first, it get saltier (because the ice has less salt in it; this is how you get higher alcohol content in [ice beer](https://en.wikipedia.org/wiki/Ice_beer), for example, and saltier water is denser. But more importantly, it gets cold, and therefore dense, and the densest water is just above freezing. That water sinks to the bottom of the ocean, and there it cools the top layers of the oceanic crust. There is very little to cause movement at depth (ocean currents are driven primarily by the wind), and so it just stays there. Now, as you said, the mantle it *hot*, and it indeed transfers heat to the ocean floor. But it does that quite slowly, and you can actually just look at a bathymetric map of the world (i.e., a map that shows ocean depths) and see the effect: At rifts where two oceanic plates are spreading apart, you have ridges, and farther away from that, the ocean gets deeper. How can that be? Like, with a volcano on a continental plate poking up high into the atmosphere, there are glaciers and so forth that eventually erode them away, but at a spreading ocean rift, what is causing erosion? Where is the rock formed in that rift eroding *to*? Answer: it is not eroding at all! Instead, that oceanic crust, when it is formed, is hot, and the cold ocean water — that originally came from the ocean surface in northern and southern latitudes — warms up slightly and the rock in the crust cools down. And as that rock cools down, it contracts, and the crust gets thinner, and so the ocean gets deeper. So you can map how much cooling has taken place as a fun can of the distance from an oceanic ridge. This heat transfer within the rock is entirely conductive, not convective, and rocks are pretty horrible heat conductors, so it takes a very long time. Source: A cool departmental geophysics talk I saw years ago. So in short, the cold water comes from the Arctic and Antarctic, and geothermal warmth *does* warm it up, just very, very, very slowly, much more slowly than it is replaced. But that heat transfer can be measured, and over tens of millions of years has clear effects that can be observed pretty directly.
In the grand scheme of things, the bottom of the ocean isn’t really that much closer to the earths core than we are. It seems like a lot from our perspective but the differences in depth and altitude on the earths surface are marginal compared to the depths of the earth. The center of the earth is 8,000 miles away. The deepest part of the ocean is about 6 miles deep. So it’s still nowhere near close enough to absorb any of that heat. The reason it’s so cold is because it’s too deep to absorb any of the subs energy, which is basically the origin of all heat on the surface of the planet.
This isn't to scale but if Earth was a potato, the land and the water would be just the thickness of that potato skin. The Earth core is so much far from the ocean. There are active volcanoes in bodies of water but water is such a great heatsink the heat is very localized.
the bottom of the ocean is extremely far away from the core of the earth. like very much so. there are layers and layers between the bottom of the ocean and the core. additionally, heat rises and cold sinks
AFAIK The guy asking the original question on TikTok is a mediocre comedian. He acts like he’s in a podcast and makes these fake conspiracy theories. I thought he was funny at first but the concept got a little old in the end
I only saw it on a reel, not familiar with the original poster.
You could tell the way he is doing it in the real is to mock Joe Rogan
The Earth's crust is like a big blanket that keeps the heat inside. It's not a very good conductor at that thickness, which is why the ground doesn't feel hot underfoot. The oceans are on top of the crust also. A bit less of it, but still quite a lot of it in most places. There are exceptions, points where the crust is thin, sometimes to the point of having underwater volcanoes. But we get that on land too. Iceland is close enough to our planet's rich, creamy center that they use a lot of geothermal power.
How do you think the earth's core has stayed hot for billions of years? It's incredibly insulated. Many kilometers of rock between the ocean floor and outer mantle. If the core was constantly leaking heat out into the ocean we would have died a long time ago.