How has Earth's core stayed as hot as the sun's surface for billions of years?

Nov 20, 2019
53
9
4,535
Visit site
these are all stupid and unsupported theories; no physical mechanism to trap all that heat during 5 billion years, no physical mechanism to explain the starting incredibly high temperature the core should have had due to the merger of planetesimals, no physical mechanism to explain the high temperature of the original dust disk around the sun, no physical mechanism to explain an hypotetical gravitational collapse of the new condensed planet earth, no physical mechanism to explain the amount of energy producing the heat by radioactivity decay, no data to show the huge loss of temperature from the core during past earth's life, no data to show the necessary production of many types of radioactive isotopes as a result of the fission process, no physical mechanism to explain why the same heat creation process is not ongoing in all the other solar system solid bodies
 
The earth remains a hard nut to crack. Our deepest attempts are only small pricks. We found it saturated with super-heated high pressure water. This water should be highly conductive. Our crust might have an electrical character to it. There might even be electrical layers in the earth, like there is above the earth.

Some studies show the gravity reaches a maximum at a shell, with a decrease in gravity inside that shell in the center. The gravity gradient under the shell might be opposite the gravity gradient above that shell. A pulling up force at the center. Wouldn't that be wild.

This water would easily flash at the surface and give a huge source of power. But it would not be free. Like other geo-hydro sites, there are contaminates in the steam and water. High maintenance and replacement repair.
 
"Where does all that heat come from? It is not from the sun. While it warms us and all the plants and animals on Earth's surface, sunlight can't penetrate through miles of the planet’s interior. Instead, there are two sources. One is the heat that Earth inherited during its formation 4.5 billion years ago. The Earth was made from the solar nebula (opens in new tab), a gigantic gaseous cloud, amid endless collisions and mergers between bits of rock and debris called planetesimals. This process took tens of millions of years. An enormous amount of heat was produced during those collisions, enough to melt the whole Earth. Although some of that heat was lost in space, the rest of it was locked away inside the Earth, where much of it remains even today. The other heat source: the decay of radioactive isotopes, distributed everywhere in the Earth."

This is view is interesting in the article. The giant impact for the origin of our Moon does not feature a fully formed Earth as we see today but a proto-earth and a proto-moon that evolves after the giant impact, thus both earth and moon must continue to grow in size and mass until what we see today. Explaining how Earth evolved in the solar nebula and Venus evolved so very differently, from the same nebula and postulated protoplanetary disc, remains very challenging. This model interpretation presented explaining the heat today, could have some holes in it.

 
Jan 26, 2023
3
2
15
Visit site
I've heard the isotope/radiation theory, and thought it was an interesting guess. Personally, I always thought the core was active due to the tidal effect of our relatively large moon.

With the constant churning of the moon's pull, the mantle stays relatively fluid, and the core oscillates within that "fluid". Resulting friction would produce a lot of heat.

I don't know a lot about the inner workings of Mars, but also assumed the lack of a large moon accounted for the dead core (though recent seismic readings suggest it's not as dead as we thought).

Venus is just plain hot. Solar accounts for the extreme temperature at the surface, but I don't know if the core is active. Same for Mercury. There are no other "rock" planets in our solar system to compare to, so my guess probably couldn't be "proven" by comparison. However, we do see evidence of active cores on moons orbiting large gas giants.
 
  • Like
Reactions: Questioner and rod
Perhaps there is heat/cooling problems in the solar system, whether Earth or some small moons or other planets. I have read over the years different reports that indicate heat/cooling issues come up when showing how something remains hot over a 4.5 Gyr solar system model.
 
these are all stupid and unsupported theories; no physical mechanism to trap all that heat during 5 billion years, no physical mechanism to explain the starting incredibly high temperature the core should have had due to the merger of planetesimals, no physical mechanism to explain the high temperature of the original dust disk around the sun, no physical mechanism to explain an hypotetical gravitational collapse of the new condensed planet earth, no physical mechanism to explain the amount of energy producing the heat by radioactivity decay, no data to show the huge loss of temperature from the core during past earth's life, no data to show the necessary production of many types of radioactive isotopes as a result of the fission process, no physical mechanism to explain why the same heat creation process is not ongoing in all the other solar system solid bodies

It does take that long to cool off, do the math. And, there is residual radioactivity keeping up the temperature. Your ramblings are the only unsupported "theories" around here . . . . .
 
Some interesting comments here in various posts. Who, what, when, where, how, and why are good investigative questions to ask.

For example, what was the original core temperature of Earth when it was a proto-earth before the giant impact with Theia - creating the Moon? The proto-earth is not the same size or mass as we live on today but smaller in size and mass. Initial conditions must be defined, heat loss rates, heat sources for adding heat, etc., accretion growth rates, etc.
 
Jan 31, 2023
1
1
15
Visit site
Given the difference in half life between U235 and U238, it is common knowledge that the natural uranium enrichment was much higher early in the earth's life. Just like there were natural reactors in 'operation' at that time (like Oklo in Gabon), perhaps the entire core (pardon the pun) was one massive yet self regulated nuclear fission reactor producing an insane amount of heat over that time. Is there evidence to suggest any significant quantities of uranium in the core?
 
  • Like
Reactions: rod
"But without the Earth's internal heat, the plates would not have been moving. The Earth would have cooled down. Our world would likely have been uninhabitable. You wouldn’t be here."

I agree 100%!!!

The earth's core is heating up the planet,
and this heat can fluctuate,
like anything else in this creation which is subject to change,
thus causing temperature fluctuations in the oceans temperature.

We call it global heating or global cooling!!!!!
 
The story totally omits tidal friction.

If radioactive decay is the/a major contributor to Earth's core heat then why has Mars lost so much heat that its ancient magnetic field disapated?
Radioactive decay should be ongoing.
Are they suggesting that Mars has a lower proportion of nuclear unstable elements?

It would be informative to know more about Venus's core since its size is close to Earth's.
 
This thread is over 1 year old.

Thermodynamics and heat transfer are well understood but solving the simple equation of conductivity takes massive amounts of computer crunching, or it used to 50 years ago. 😀We had to use analog computers to do this work,

The average heat transfer rate to the surface is dependent on variables including;
Core temp.
Convective transfer
Radioactive decay rates (greatly diminished at this point)
Mantle conductivity

When Lord Kelvin estimated the Earth’s age he used deep mine temps. But he was unaware of radioactivity, at least initially. I think he also didn’t consider convective rates adequately. Thus he saw temps hotter than expected leading him to his estimates for Earth’s age of 20 M to 100 M years.
 
Last edited:
Maybe our core was cold at moon's collision. The moon's core was injected into our core and reached critical mass. The new core begins to heat and melt, heating the planet up. And causing plates to move. And our moon is cold slag.

The gravity gradient, the density gradient, and the rotation, sets the throttle for the heat flow. Both gradients might be much different than what we think.

A nuclear core might be a requirement for a living planet. Local radiation might even be a requirement for evolution, if you believe in such. Mild neutron radiation might drastically reduce the time needed for the right organic molecules to pattern.

It might have taken two to tango.
 
FWIW, nuclear fission is not an on or off reactor. If there is uranium in a mixture of rock, there will be some neutrons hitting uranium atoms and causing them to fission. If the number of neutrons released by a fission creates less than one additional fission, then the reaction is called "sub-critical". It would decays away to nothing if there were not some spontaneous neutron emissions to keep it going. Subcritical reactors have a "multiplication factor" that is less than one. But, they do produce more energy than comes from simple radioactive decay of the uranium.

To complete the story, a reactor is "critical" when the number of neutrons released by one fission create (on average) exactly 1.0 more fission event, so the power release stays unchanged from one set of fissions to the next set. If the number of fissions in successive fissions increases, the reaction is called "super-critical". So long as the criticality ratio stays less than about 1.006, there is a relatively slow increase in the total power output. Above that level of "super-criticality" you get into atomic bomb territory. That is because about 0.0065% of the neutrons resulting from a fission do not get emitted immediately, but instead, are released with a little bit of delay by radioactive fission products that emit neutrons as they quickly decay. So, there is a really abrupt change in the rate of power increase when the fission chain reaction becomes "critical" on just the fraction of the neutrons that are released immediately with the fission of a uranium nucleus. That is called "prompt critical" and is what happened in the Chernobyl reactor accident in Russia.

The "natural reactors" in Oklo, Africa, occurred long ago when there was more U-235 than today, and were apparently self-limiting. For one thing, they were the type of reactor that has the neutrons slowed down by bouncing off hydrogen atoms, with the slower neutrons having a higher probability of causing a fission when they hit a uranium atom than if they were going as fast as they started with the fission event. If there is no water around to slow the fission neutrons before they hit another uranium atom, the concentration of uranium needed to make a "fast (neutron) reactor" critical is much higher.

What the concentration of uranium is in the Earth's core, and how the physics of fission behaves at such immense pressures and temperatures, is somewhat speculative.
 
  • Like
Reactions: Helio
The amount of radioactive decay is in half-lives.
Half decays/transmutates to some other element.
So in K years -> N/2;
In the next K years -> N/4
then -> N/8
etc.
So it's an ever declining amount of energy from a given element, but some elements decay to other relatively nuclear unstable elements and some to relatively nuclear stable elements.

So the radioactive decay heat source does tend to decline over the long run.