How does the Earth's center produce heat?Does heat from gravitational pressure dissipate eventually?What happens with the force of gravity when the distance between two objects is 0?What is the energy required to create mass of m at a height of h above the Earth?Gravitational potential energy and center of massCan Gravity be used as an energy source?Why is work path dependent for gas expansion?Work done pumping water with a 6 foot static headIs the ocean guaranteed to warm in a warming climate?Is the normal force smaller than gravitational force due to earth's rotation?Does dark matter need a second force to collect in ordinary matter?
Adobe Illustrator: How can I change the profile of a dashed stroke?
Three knights or knaves, three different hair colors
How do I write real-world stories separate from my country of origin?
How to safely discharge oneself
Why do testers need root cause analysis?
Existence of a model of ZFC in which the natural numbers are really the natural numbers
Is there an idiom that means that you are in a very strong negotiation position in a negotiation?
What is the required burn to keep a satellite at a Lagrangian point?
"Official wife" or "Formal wife"?
Can diplomats be allowed on the flight deck of a commercial European airline?
Is ideal gas incompressible?
Does attacking (or having a rider attack) cancel Charge/Pounce-like abilities?
Why the work done is positive when bringing 2 opposite charges together?
Passport queue length in UK in relation to arrival method
JavaScript: Access 'this' when calling function stored in variable
Why is this integration method not valid?
VHDL: Why is it hard to desgin a floating point unit in hardware?
How could the B-29 bomber back up under its own power?
How to test if argument is a single space?
To exponential digit growth and beyond!
Keeping the dodos out of the field
size of pointers and architecture
Efficient Algorithms for Destroyed Document Reconstruction
Why is unzipped file smaller than zipped file
How does the Earth's center produce heat?
Does heat from gravitational pressure dissipate eventually?What happens with the force of gravity when the distance between two objects is 0?What is the energy required to create mass of m at a height of h above the Earth?Gravitational potential energy and center of massCan Gravity be used as an energy source?Why is work path dependent for gas expansion?Work done pumping water with a 6 foot static headIs the ocean guaranteed to warm in a warming climate?Is the normal force smaller than gravitational force due to earth's rotation?Does dark matter need a second force to collect in ordinary matter?
$begingroup$
In my understanding, the center of the Earth is hot because of the weight of the its own matter being crushed in on itself because of gravity. We can use water to collect this heat from the Earth and produce electricity with turbines. However, I'd imagine that doing this at an enormous, impossibly large scale would not cool the center of the Earth to the same temperature as the surface, since gravity is still compressing the rock together.
However, since energy cannot be created or destroyed, it seems like this energy is just coming from nowhere. I doubt the Earth's matter is being slowly consumed to generate this energy, or that the sun is somehow causing the heating.
I think that I have misunderstood or overlooked some important step in this process. If so, why (or why not) does the Earth's center heat up, and, if not, does geothermal energy production cool it down irreversibly?
thermodynamics gravity
$endgroup$
add a comment |
$begingroup$
In my understanding, the center of the Earth is hot because of the weight of the its own matter being crushed in on itself because of gravity. We can use water to collect this heat from the Earth and produce electricity with turbines. However, I'd imagine that doing this at an enormous, impossibly large scale would not cool the center of the Earth to the same temperature as the surface, since gravity is still compressing the rock together.
However, since energy cannot be created or destroyed, it seems like this energy is just coming from nowhere. I doubt the Earth's matter is being slowly consumed to generate this energy, or that the sun is somehow causing the heating.
I think that I have misunderstood or overlooked some important step in this process. If so, why (or why not) does the Earth's center heat up, and, if not, does geothermal energy production cool it down irreversibly?
thermodynamics gravity
$endgroup$
$begingroup$
Some of it is due to radioactive decay, the Earth Sciences StackExcange will know the numbers.
$endgroup$
– Pieter
5 hours ago
add a comment |
$begingroup$
In my understanding, the center of the Earth is hot because of the weight of the its own matter being crushed in on itself because of gravity. We can use water to collect this heat from the Earth and produce electricity with turbines. However, I'd imagine that doing this at an enormous, impossibly large scale would not cool the center of the Earth to the same temperature as the surface, since gravity is still compressing the rock together.
However, since energy cannot be created or destroyed, it seems like this energy is just coming from nowhere. I doubt the Earth's matter is being slowly consumed to generate this energy, or that the sun is somehow causing the heating.
I think that I have misunderstood or overlooked some important step in this process. If so, why (or why not) does the Earth's center heat up, and, if not, does geothermal energy production cool it down irreversibly?
thermodynamics gravity
$endgroup$
In my understanding, the center of the Earth is hot because of the weight of the its own matter being crushed in on itself because of gravity. We can use water to collect this heat from the Earth and produce electricity with turbines. However, I'd imagine that doing this at an enormous, impossibly large scale would not cool the center of the Earth to the same temperature as the surface, since gravity is still compressing the rock together.
However, since energy cannot be created or destroyed, it seems like this energy is just coming from nowhere. I doubt the Earth's matter is being slowly consumed to generate this energy, or that the sun is somehow causing the heating.
I think that I have misunderstood or overlooked some important step in this process. If so, why (or why not) does the Earth's center heat up, and, if not, does geothermal energy production cool it down irreversibly?
thermodynamics gravity
thermodynamics gravity
asked 5 hours ago
Redwolf ProgramsRedwolf Programs
1085
1085
$begingroup$
Some of it is due to radioactive decay, the Earth Sciences StackExcange will know the numbers.
$endgroup$
– Pieter
5 hours ago
add a comment |
$begingroup$
Some of it is due to radioactive decay, the Earth Sciences StackExcange will know the numbers.
$endgroup$
– Pieter
5 hours ago
$begingroup$
Some of it is due to radioactive decay, the Earth Sciences StackExcange will know the numbers.
$endgroup$
– Pieter
5 hours ago
$begingroup$
Some of it is due to radioactive decay, the Earth Sciences StackExcange will know the numbers.
$endgroup$
– Pieter
5 hours ago
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
Heating because of high pressure is mostly an issue in gases, where gravitational adiabatic compression can bring up the temperature a lot (e.g. in stellar cores). It is not really the source of geothermal heat.
Earth's interior is hot because of three main contributions:
"Primordial heat": energy left over from when the planet coalesced. The total binding energy of Earth is huge ($2cdot 10^32$ J) and when the planetesimals that formed Earth collided and merged they had to convert their kinetic energy into heat. This contributes 5-30 TW of energy flow today.
"Differentiation heat": the original mix of Earth was likely relatively even, but heavy elements would tend to sink towards the core while lighter would float up towards the upper mantle. This releases potential energy.
"Radiogenic heat": The Earth contains a certain amount of radioactive elements that decay, heating up the interior. The ones that matter now are the ones that have half-lives comparable with the age of Earth and high enough concentrations; these are $^40$K, $^232$Th, $^235$U and $^238$U. The heat flow due to this is 15-41 TW.
Note that we know the total heat flow rather well, about 45 TW, but the relative strengths of the primordial and radiogenic heat are not well constrained.
The energy is slowly being depleted, although at a slow rate: the thermal conductivity and size of Earth make the heat flow out rather slowly. Geothermal energy plants may cool down crustal rocks locally at a faster rate, getting less efficient over time if they take too much heat. But it has no major effect on the whole system, which is far larger.
$endgroup$
$begingroup$
This answer misses heat generated by the coalescence of the Earth's outer core onto the Earth's inner core.
$endgroup$
– David Hammen
1 hour ago
add a comment |
$begingroup$
First things first: Human activity is not tapping into the heat of the Earth's core. At best, we're tapping into the heat differential between the surface and tens of meters to perhaps a several hundred meters below the surface. Temperature in general increases with increasing depth. We humans don't have the technology to penetrate several kilometers below the surface of the Earth, let alone the technology needed to penetrate the six thousand plus kilometers needed to reach the center of the Earth.
That said, the Earth's core does produce heat. It retains a bleep ton heat (read a crude four letter word instead of "bleep") from its initial formation. This initial heat came in two forms. One was a result of collisions. Even more heat was generated when the Earth separated into a core, mantle, and crust. This is where the bleep ton comes into play. The Earth has only had 4.5 billion years to radiate away that huge amount of heat. That's too short of a period of time for that huge amount of heat.
Regarding heat production, the Earth's core produces heat via the conversion of molten material in the Earth's molten outer core to solid material in the Earth's solid inner core. The Earth's core may also produce heat via radioactive decay of material within the Earth's core, but this is highly debatable. The four main long-lived radioactive isotopes (uranium 238 and 235, thorium 232, and potassium 40) are chemically incompatible with migration to the Earth's core. are chemically incompatible with migration to the Earth's core. The former source of heat (an increase in the size of the Earth's inner core) is widely accepted. The latter (radioactive decay in the Earth's core) is anything but widely accepted.
$endgroup$
$begingroup$
My point about taking energy from the Earth's core is that taking it from the crust would cool the crust, which would be heated up again by the mantle, which would be heated by the core.
$endgroup$
– Redwolf Programs
1 hour ago
add a comment |
Your Answer
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "151"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f481149%2fhow-does-the-earths-center-produce-heat%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Heating because of high pressure is mostly an issue in gases, where gravitational adiabatic compression can bring up the temperature a lot (e.g. in stellar cores). It is not really the source of geothermal heat.
Earth's interior is hot because of three main contributions:
"Primordial heat": energy left over from when the planet coalesced. The total binding energy of Earth is huge ($2cdot 10^32$ J) and when the planetesimals that formed Earth collided and merged they had to convert their kinetic energy into heat. This contributes 5-30 TW of energy flow today.
"Differentiation heat": the original mix of Earth was likely relatively even, but heavy elements would tend to sink towards the core while lighter would float up towards the upper mantle. This releases potential energy.
"Radiogenic heat": The Earth contains a certain amount of radioactive elements that decay, heating up the interior. The ones that matter now are the ones that have half-lives comparable with the age of Earth and high enough concentrations; these are $^40$K, $^232$Th, $^235$U and $^238$U. The heat flow due to this is 15-41 TW.
Note that we know the total heat flow rather well, about 45 TW, but the relative strengths of the primordial and radiogenic heat are not well constrained.
The energy is slowly being depleted, although at a slow rate: the thermal conductivity and size of Earth make the heat flow out rather slowly. Geothermal energy plants may cool down crustal rocks locally at a faster rate, getting less efficient over time if they take too much heat. But it has no major effect on the whole system, which is far larger.
$endgroup$
$begingroup$
This answer misses heat generated by the coalescence of the Earth's outer core onto the Earth's inner core.
$endgroup$
– David Hammen
1 hour ago
add a comment |
$begingroup$
Heating because of high pressure is mostly an issue in gases, where gravitational adiabatic compression can bring up the temperature a lot (e.g. in stellar cores). It is not really the source of geothermal heat.
Earth's interior is hot because of three main contributions:
"Primordial heat": energy left over from when the planet coalesced. The total binding energy of Earth is huge ($2cdot 10^32$ J) and when the planetesimals that formed Earth collided and merged they had to convert their kinetic energy into heat. This contributes 5-30 TW of energy flow today.
"Differentiation heat": the original mix of Earth was likely relatively even, but heavy elements would tend to sink towards the core while lighter would float up towards the upper mantle. This releases potential energy.
"Radiogenic heat": The Earth contains a certain amount of radioactive elements that decay, heating up the interior. The ones that matter now are the ones that have half-lives comparable with the age of Earth and high enough concentrations; these are $^40$K, $^232$Th, $^235$U and $^238$U. The heat flow due to this is 15-41 TW.
Note that we know the total heat flow rather well, about 45 TW, but the relative strengths of the primordial and radiogenic heat are not well constrained.
The energy is slowly being depleted, although at a slow rate: the thermal conductivity and size of Earth make the heat flow out rather slowly. Geothermal energy plants may cool down crustal rocks locally at a faster rate, getting less efficient over time if they take too much heat. But it has no major effect on the whole system, which is far larger.
$endgroup$
$begingroup$
This answer misses heat generated by the coalescence of the Earth's outer core onto the Earth's inner core.
$endgroup$
– David Hammen
1 hour ago
add a comment |
$begingroup$
Heating because of high pressure is mostly an issue in gases, where gravitational adiabatic compression can bring up the temperature a lot (e.g. in stellar cores). It is not really the source of geothermal heat.
Earth's interior is hot because of three main contributions:
"Primordial heat": energy left over from when the planet coalesced. The total binding energy of Earth is huge ($2cdot 10^32$ J) and when the planetesimals that formed Earth collided and merged they had to convert their kinetic energy into heat. This contributes 5-30 TW of energy flow today.
"Differentiation heat": the original mix of Earth was likely relatively even, but heavy elements would tend to sink towards the core while lighter would float up towards the upper mantle. This releases potential energy.
"Radiogenic heat": The Earth contains a certain amount of radioactive elements that decay, heating up the interior. The ones that matter now are the ones that have half-lives comparable with the age of Earth and high enough concentrations; these are $^40$K, $^232$Th, $^235$U and $^238$U. The heat flow due to this is 15-41 TW.
Note that we know the total heat flow rather well, about 45 TW, but the relative strengths of the primordial and radiogenic heat are not well constrained.
The energy is slowly being depleted, although at a slow rate: the thermal conductivity and size of Earth make the heat flow out rather slowly. Geothermal energy plants may cool down crustal rocks locally at a faster rate, getting less efficient over time if they take too much heat. But it has no major effect on the whole system, which is far larger.
$endgroup$
Heating because of high pressure is mostly an issue in gases, where gravitational adiabatic compression can bring up the temperature a lot (e.g. in stellar cores). It is not really the source of geothermal heat.
Earth's interior is hot because of three main contributions:
"Primordial heat": energy left over from when the planet coalesced. The total binding energy of Earth is huge ($2cdot 10^32$ J) and when the planetesimals that formed Earth collided and merged they had to convert their kinetic energy into heat. This contributes 5-30 TW of energy flow today.
"Differentiation heat": the original mix of Earth was likely relatively even, but heavy elements would tend to sink towards the core while lighter would float up towards the upper mantle. This releases potential energy.
"Radiogenic heat": The Earth contains a certain amount of radioactive elements that decay, heating up the interior. The ones that matter now are the ones that have half-lives comparable with the age of Earth and high enough concentrations; these are $^40$K, $^232$Th, $^235$U and $^238$U. The heat flow due to this is 15-41 TW.
Note that we know the total heat flow rather well, about 45 TW, but the relative strengths of the primordial and radiogenic heat are not well constrained.
The energy is slowly being depleted, although at a slow rate: the thermal conductivity and size of Earth make the heat flow out rather slowly. Geothermal energy plants may cool down crustal rocks locally at a faster rate, getting less efficient over time if they take too much heat. But it has no major effect on the whole system, which is far larger.
answered 3 hours ago
Anders SandbergAnders Sandberg
11k21532
11k21532
$begingroup$
This answer misses heat generated by the coalescence of the Earth's outer core onto the Earth's inner core.
$endgroup$
– David Hammen
1 hour ago
add a comment |
$begingroup$
This answer misses heat generated by the coalescence of the Earth's outer core onto the Earth's inner core.
$endgroup$
– David Hammen
1 hour ago
$begingroup$
This answer misses heat generated by the coalescence of the Earth's outer core onto the Earth's inner core.
$endgroup$
– David Hammen
1 hour ago
$begingroup$
This answer misses heat generated by the coalescence of the Earth's outer core onto the Earth's inner core.
$endgroup$
– David Hammen
1 hour ago
add a comment |
$begingroup$
First things first: Human activity is not tapping into the heat of the Earth's core. At best, we're tapping into the heat differential between the surface and tens of meters to perhaps a several hundred meters below the surface. Temperature in general increases with increasing depth. We humans don't have the technology to penetrate several kilometers below the surface of the Earth, let alone the technology needed to penetrate the six thousand plus kilometers needed to reach the center of the Earth.
That said, the Earth's core does produce heat. It retains a bleep ton heat (read a crude four letter word instead of "bleep") from its initial formation. This initial heat came in two forms. One was a result of collisions. Even more heat was generated when the Earth separated into a core, mantle, and crust. This is where the bleep ton comes into play. The Earth has only had 4.5 billion years to radiate away that huge amount of heat. That's too short of a period of time for that huge amount of heat.
Regarding heat production, the Earth's core produces heat via the conversion of molten material in the Earth's molten outer core to solid material in the Earth's solid inner core. The Earth's core may also produce heat via radioactive decay of material within the Earth's core, but this is highly debatable. The four main long-lived radioactive isotopes (uranium 238 and 235, thorium 232, and potassium 40) are chemically incompatible with migration to the Earth's core. are chemically incompatible with migration to the Earth's core. The former source of heat (an increase in the size of the Earth's inner core) is widely accepted. The latter (radioactive decay in the Earth's core) is anything but widely accepted.
$endgroup$
$begingroup$
My point about taking energy from the Earth's core is that taking it from the crust would cool the crust, which would be heated up again by the mantle, which would be heated by the core.
$endgroup$
– Redwolf Programs
1 hour ago
add a comment |
$begingroup$
First things first: Human activity is not tapping into the heat of the Earth's core. At best, we're tapping into the heat differential between the surface and tens of meters to perhaps a several hundred meters below the surface. Temperature in general increases with increasing depth. We humans don't have the technology to penetrate several kilometers below the surface of the Earth, let alone the technology needed to penetrate the six thousand plus kilometers needed to reach the center of the Earth.
That said, the Earth's core does produce heat. It retains a bleep ton heat (read a crude four letter word instead of "bleep") from its initial formation. This initial heat came in two forms. One was a result of collisions. Even more heat was generated when the Earth separated into a core, mantle, and crust. This is where the bleep ton comes into play. The Earth has only had 4.5 billion years to radiate away that huge amount of heat. That's too short of a period of time for that huge amount of heat.
Regarding heat production, the Earth's core produces heat via the conversion of molten material in the Earth's molten outer core to solid material in the Earth's solid inner core. The Earth's core may also produce heat via radioactive decay of material within the Earth's core, but this is highly debatable. The four main long-lived radioactive isotopes (uranium 238 and 235, thorium 232, and potassium 40) are chemically incompatible with migration to the Earth's core. are chemically incompatible with migration to the Earth's core. The former source of heat (an increase in the size of the Earth's inner core) is widely accepted. The latter (radioactive decay in the Earth's core) is anything but widely accepted.
$endgroup$
$begingroup$
My point about taking energy from the Earth's core is that taking it from the crust would cool the crust, which would be heated up again by the mantle, which would be heated by the core.
$endgroup$
– Redwolf Programs
1 hour ago
add a comment |
$begingroup$
First things first: Human activity is not tapping into the heat of the Earth's core. At best, we're tapping into the heat differential between the surface and tens of meters to perhaps a several hundred meters below the surface. Temperature in general increases with increasing depth. We humans don't have the technology to penetrate several kilometers below the surface of the Earth, let alone the technology needed to penetrate the six thousand plus kilometers needed to reach the center of the Earth.
That said, the Earth's core does produce heat. It retains a bleep ton heat (read a crude four letter word instead of "bleep") from its initial formation. This initial heat came in two forms. One was a result of collisions. Even more heat was generated when the Earth separated into a core, mantle, and crust. This is where the bleep ton comes into play. The Earth has only had 4.5 billion years to radiate away that huge amount of heat. That's too short of a period of time for that huge amount of heat.
Regarding heat production, the Earth's core produces heat via the conversion of molten material in the Earth's molten outer core to solid material in the Earth's solid inner core. The Earth's core may also produce heat via radioactive decay of material within the Earth's core, but this is highly debatable. The four main long-lived radioactive isotopes (uranium 238 and 235, thorium 232, and potassium 40) are chemically incompatible with migration to the Earth's core. are chemically incompatible with migration to the Earth's core. The former source of heat (an increase in the size of the Earth's inner core) is widely accepted. The latter (radioactive decay in the Earth's core) is anything but widely accepted.
$endgroup$
First things first: Human activity is not tapping into the heat of the Earth's core. At best, we're tapping into the heat differential between the surface and tens of meters to perhaps a several hundred meters below the surface. Temperature in general increases with increasing depth. We humans don't have the technology to penetrate several kilometers below the surface of the Earth, let alone the technology needed to penetrate the six thousand plus kilometers needed to reach the center of the Earth.
That said, the Earth's core does produce heat. It retains a bleep ton heat (read a crude four letter word instead of "bleep") from its initial formation. This initial heat came in two forms. One was a result of collisions. Even more heat was generated when the Earth separated into a core, mantle, and crust. This is where the bleep ton comes into play. The Earth has only had 4.5 billion years to radiate away that huge amount of heat. That's too short of a period of time for that huge amount of heat.
Regarding heat production, the Earth's core produces heat via the conversion of molten material in the Earth's molten outer core to solid material in the Earth's solid inner core. The Earth's core may also produce heat via radioactive decay of material within the Earth's core, but this is highly debatable. The four main long-lived radioactive isotopes (uranium 238 and 235, thorium 232, and potassium 40) are chemically incompatible with migration to the Earth's core. are chemically incompatible with migration to the Earth's core. The former source of heat (an increase in the size of the Earth's inner core) is widely accepted. The latter (radioactive decay in the Earth's core) is anything but widely accepted.
answered 1 hour ago
David HammenDavid Hammen
34k759110
34k759110
$begingroup$
My point about taking energy from the Earth's core is that taking it from the crust would cool the crust, which would be heated up again by the mantle, which would be heated by the core.
$endgroup$
– Redwolf Programs
1 hour ago
add a comment |
$begingroup$
My point about taking energy from the Earth's core is that taking it from the crust would cool the crust, which would be heated up again by the mantle, which would be heated by the core.
$endgroup$
– Redwolf Programs
1 hour ago
$begingroup$
My point about taking energy from the Earth's core is that taking it from the crust would cool the crust, which would be heated up again by the mantle, which would be heated by the core.
$endgroup$
– Redwolf Programs
1 hour ago
$begingroup$
My point about taking energy from the Earth's core is that taking it from the crust would cool the crust, which would be heated up again by the mantle, which would be heated by the core.
$endgroup$
– Redwolf Programs
1 hour ago
add a comment |
Thanks for contributing an answer to Physics Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f481149%2fhow-does-the-earths-center-produce-heat%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
$begingroup$
Some of it is due to radioactive decay, the Earth Sciences StackExcange will know the numbers.
$endgroup$
– Pieter
5 hours ago