Earth - What is the real age?

[swansont]

To be fair to David, a rapidly collapsing magnetic field could induce some heating.

This repeated set-up and collapse of magnetic fields is how induction heating works.

 

The effect would certainly not be sufficient to explain Venus as David seems to think.

 

There's a little more to it than that. The varying field causes heating by inducing currents in a conductor, and the resistive losses show up as heating. It's not going to work on something that doesn't conduct e.g. a ceramic, or rock.

I am not a geologists and I'd like Ophilite to comment, for I keep seeing geological formations that make me think the surface of the planet was never really totally molten, but that is too much from a layman's point of view and not an expert.

 

A lot can happen in a few billion years. Very little of the earth's surface dates back 4 billion years.

 

Edit: In you compost pile example, the bacteria which are generating the heat are reproducing, i.e. more of them come on the scene. The radioisotopes in a core are not reproducing, they are decaying.

 

But in decaying they heat the interior. Adding insulation in that situation could raise the core temperature.

[Essay]

I am not a geologists and I'd like Ophilite to comment, for I keep seeing geological formations that make me think the surface of the planet was never really totally molten, but that is too much from a layman's point of view and not an expert.

 

I think most of what we see on the surface now is sedimentary (or metamorphosed sediments) in nature ...often from eroded igneous origins if not other eroded meta/sediments, so you'd be correct; but I'd like to hear from Ophiolite too ...eventually (no pressure).

 

~

[Robittybob1]

 

...A lot can happen in a few billion years. Very little of the earth's surface dates back 4 billion years.

...

That is the bit that is harder to comprehend. Mountains might be a few million years old old billions. You are right. Thanks.

[David Levy]

Thanks for the support

 

To be fair to David, a rapidly collapsing magnetic field could induce some heating.

This repeated set-up and collapse of magnetic fields is how induction heating works.

 

The effect would certainly not be sufficient to explain Venus as David seems to think.

 

 

We have discovered that Venus and Earth are quite similar (Sister planets), but there is significant different in their surface temperature.

Therefore, it might be a mistake to use a formula without deep understanding on the real process on each planet.

 

 

 

The short answer is that bodies radiate as T⁴ (space is very cold, so the incoming radiation from space is negligible). That is a body at 1200K radiates ~300x as much power as one at 290K.

 

 

There are so many factors to discover before using those kinds of formulas. I have already highlight some factors but there are more. Those factors are not constant. There are changes over time.

For example – Atmosphere and Crust heat conductance,

-Atmosphere must have a significant impact on our calculation for the power radiated from a black body in terms of its temperature:

http://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law#Temperature_of_the_Earth

"This gives an effective temperature of 6 °C on the surface of the Earth, assuming that it perfectly absorbs all emission falling on it and has no atmosphere."

The Earth has an albedo of 0.3, meaning that 30% of the solar radiation that hits the planet gets scattered back into space without absorption

However, we don't know for sure what kind of atmosphere the Earth or Venus have 4500 My ago.

-Crust heat conductance

 

 

There's a little more to it than that. The varying field causes heating by inducing currents in a conductor, and the resistive losses show up as heating. It's not going to work on something that doesn't conduct e.g. a ceramic, or rock.

 

Let's assume that a thin crust covers the earth at a temp of 500 while the whole internal Earth temperature was 6000. This should have a great impact on our calculation for black body's thermodynamic temperature. Now we have to use 500 instead of 6000. Therefore, this factor by itself can set a significantly change in the requested time which is needed to cool down the Earth.

Edited March 27, 2015 by David Levy

[pavelcherepan]

We have discovered that Venus and Earth are quite similar (Sister planets), but there is significant different in their surface temperature.

Therefore, it might be a mistake to use a formula without deep understanding on the real process on each planet.

 

Who are 'we' or is it a quote? the Earth and Venus are called 'sister planets' mostly for the size, mass and overall composition. Their histories are very different based on what science knows, but there's no need to involve Venus in the first place, because we're talking about the Earth and as far as I'm concerned, Ophiolite had given you a great summary of the current knowledge of the formation of the Earth and its age. What do you not understand from what he wrote?

 

I would also like to note that aligning your text to the right makes it really hard to read and that's probably why no one else uses it. Looking at your post I constantly get a feeling that I have my laptop upside down.

 

 

There are so many factors to discover before using those kinds of formulas. I have already highlight some factors but there are more. Those factors are not constant. There are changes over time.

For example – Atmosphere and Crust heat conductance,

-Atmosphere must have a significant impact on our calculation for the power radiated from a black body in terms of its temperature:

http://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law#Temperature_of_the_Earth

"This gives an effective temperature of 6 °C on the surface of the Earth, assuming that it perfectly absorbs all emission falling on it and has no atmosphere."

The Earth has an albedo of 0.3, meaning that 30% of the solar radiation that hits the planet gets scattered back into space without absorption

However, we don't know for sure what kind of atmosphere the Earth or Venus have 4500 My ago.

-Crust heat conductance

Let's assume that a thin crust covers the earth at a temp of 500 while the whole internal Earth temperature was 6000. This should have a great impact on our calculation for black body's thermodynamic temperature. Now we have to use 500 instead of 6000. Therefore, this factor by itself can set a significantly change in the requested time which is needed to cool down the Earth.

 

David, it appears to me that you didn't read or didn't understand what your opponents have said before and now without any understanding of their arguments you keep throwing in some random numbers into your random calculations. How is this going to help your point? Do you have or do you not have evidence to support your idea that the Earth is older?

Edited March 27, 2015 by pavelcherepan

[Mordred]

David one thing to note, the age of our solar system is determined by a variety of tests. Those tests don't just include samples from Earth, nor thermodynamic processes. They also include dating samples from the moon, and meteorites. By dating the age of the protoplanetary disk, as well as the sun itself. We can constrain the age significantly.

 

Here is one process of many in use.

 

http://www.google.ca/url?sa=t&source=web&cd=4&ved=0CC0QFjAD&url=http%3A%2F%2Fwww.psrd.hawaii.edu%2FNov12%2FPSRD-ages-CAIs-chondrules.pdf&rct=j&q=The%20Absolute%20Chronology%20and%20Thermal%20Processing%20of%20Solids%20in%20the%20Solar%20Protoplanetary%20Disk&ei=k9kUVYWqDoS1ggTNv4HwDg&usg=AFQjCNG34qgwTUEwgU2wqhg6dHxg7LOkOQ&sig2=XKbP_XRYdR0sGjSxiIsLMw

Edited March 27, 2015 by Mordred

[David Levy]

David one thing to note, the age of our solar system is determined by a variety of tests. Those tests don't just include samples from Earth, nor thermodynamic processes. They also include dating samples from the moon, and meteorites. By dating the age of the protoplanetary disk, as well as the sun itself. We can constrain the age significantly.

 

 

Thanks Mordred

Why can't we just focus on Earth?

Think about the following:

Oldest rock on Earth – The oldest rock which had found on Earth is about 4.4 Billion years. However, the Earth is very active planet, as its rocks are weathered, eroded, folded, and remelted. Now add to that the convection process. Therefore, it is expected that all the oldest rocks are located at least several km below the surface of the Earth or even destroyed long time ago. Hence, from statistical point of view, the rock which had been found couldn't be the real oldest one. Therefore, we could make some statistical calculation and get estimation what might be the age of the real oldest rock on Earth.

Venus - The age of Venus is similar to Earth, they are located nearby and they are quite similar with their mass. We know for sure that the temperature on Earth was cold enough to sustain water for at least 4.4 By. However, we also know that Venus is significantly hotter. Therefore, it is quite pathetic to convince our self by some kind of T4 formula. It didn't work for Venus and therefore, it might not be applicable for Earth.

There are several other indication that the Earth is older, so what?

Why the science insists that the age of the Earth must be younger than 4.6 By.

Why is it? What kind of catastrophic could happen if it is 6, 10 or even 12 billion years? (I had an impression that as long as it is younger than the age of the universe based on BBT than it is O.K.)

So, why the scientists are in panic?

Edited March 27, 2015 by David Levy

[Strange]

So, why the scientists are in panic?

 

Why do you think scientists are in a panic? They just look at the evidence and come to conclusions.

[Phi for All]

David one thing to note, the age of our solar system is determined by a variety of tests. Those tests don't just include samples from Earth, nor thermodynamic processes. They also include dating samples from the moon, and meteorites. By dating the age of the protoplanetary disk, as well as the sun itself. We can constrain the age significantly.

Thanks Mordred

Why can't we just focus on Earth?

David one thing to note, the age of our solar system is determined by a variety of tests. Those tests don't just include samples from Earth, nor thermodynamic processes. They also include dating samples from the moon, and meteorites. By dating the age of the protoplanetary disk, as well as the sun itself. We can constrain the age significantly.

Thanks Mordred

Why can't we just focus on Earth?

 

You may be reading, but you aren't reasoning through it. You're ignoring really good supportive evidence because it doesn't fit with what you think you know.

 

You're simultaneously claiming that we don't know enough to do the calculations properly, and that we shouldn't look at corroborating evidence outside of Earth. You're artificially restraining me, and then claiming I'm incapable of movement. That's not how it works.

[David Levy]

 

You may be reading, but you aren't reasoning through it. You're ignoring really good supportive evidence because it doesn't fit with what you think you know.

 

You're simultaneously claiming that we don't know enough to do the calculations properly, and that we shouldn't look at corroborating evidence outside of Earth. You're artificially restraining me, and then claiming I'm incapable of movement. That's not how it works.

 

Well, sorry if I missed the reply.

But, would you kindly answer the following:

 

Oldest rock on Earth – The oldest rock which had found on Earth is about 4.4 Billion years. However, the Earth is very active planet, as its rocks are weathered, eroded, folded, and remelted. Now add to that the convection process. Therefore, it is expected that all the oldest rocks are located at least several km below the surface of the Earth or even destroyed long time ago. Hence, from statistical point of view, the rock which had been found couldn't be the real oldest one.

Therefore, do you agree that we have to make some statistical calculation and get better estimation about the real age of the oldest rock on Earth?

Do you agree that the real old rocks might be located deep below the surface of the Earth?

 

Venus - The age of Venus is similar to Earth, they are located nearby and they are quite similar with their mass. We know for sure that the temperature on Earth was cold enough to sustain water for at least 4.4 By. However, we also know that Venus is significantly hotter. Therefore, do you agree that T4 formula is not relevant to Venus? And as it is not relevant to Venus, how can we trust it for the Earth?

 

Atmosphere - it must have a significant impact on our calculation for the power radiated from a black body in terms of its temperature:

"The Earth has an albedo of 0.3, meaning that 30% of the solar radiation that hits the planet gets scattered back into space without absorption"

How do we know what was the albedo of the Earth during the first 100 My?

 

Crust heat conductance - Let's assume that a thin crust covers the earth at a temp of 500 while the whole internal Earth temperature was 6000. This should have a great impact on our calculation for black body's thermodynamic temperature. Now we have to use 500 instead of 6000.

Therefore, Do you agree that this factor by itself could set a significantly change in the requested time which is needed to cool down the Earth?

Edited March 27, 2015 by David Levy

[Strange]

 

Therefore, do you agree that T4 formula is not relevant to Venus?

 

Of course it is relevant to Venus. It is basic thermodynamics. It is relevant to all bodies. This is getting even more ludicrous than your attempts to disprove gravity.

[David Levy]

 

Of course it is relevant to Venus. It is basic thermodynamics. It is relevant to all bodies. This is getting even more ludicrous than your attempts to disprove gravity.

 

O.K.

Let's agree that It is relevant to Venus.

 

However, we are using this formula to prove why the Earth had been cooled down in less than 100 My.

So would you kindly explain why by using the same formula on Venus, we find that Venus isn't cool enough to sustain water (even after 4.5 By)?

Edited March 27, 2015 by David Levy

[Greg H.]

It receives a good deal more solar radiation, and has a much thicker atmosphere, both of which conspire to keep the surface temperature much higher. However, Venus is in equilibirum in terms of heat in versus heat out, just like Earth.

 

The inverse square law applies here. Venus orbits at .72 of the earth's mean orbital radius, which means it receives about twice as much solar energy per square meter of surface area as the earth does (assuming my math is right).

Edited March 27, 2015 by Greg H.

[Strange]

And Venus certainly isn't hot enough the keep it molten. Compared to the early (molten) Earth, both planets are at pretty much the same temperature.

 

David, just come out with it. What is your agenda here? Some sort of creationism? Or that the world must be infinitely old? Or just a general dislike of science?

Edited March 27, 2015 by Strange

[Greg H.]

Keep in mind too that in some places on Earth, it already routinely gets to half the boiling point of water (or hotter) during the day. A little closer to the sun, and it wouldn't be hard to imagine a scenario where all the water boils off, and joins the atmosphere as water vapor, insulating the planet and further raising the surface temperature.

 

Sound like another planet we've been discussing?

[David Levy]

It receives a good deal more solar radiation, and has a much thicker atmosphere, both of which conspire to keep the surface temperature much higher. However, Venus is in equilibirum in terms of heat in versus heat out, just like Earth.

 

The inverse square law applies here. Venus orbits at .72 of the earth's mean orbital radius, which means it receives about twice as much solar energy per square meter of surface area as the earth does (assuming my math is right).

 

Thanks

 

That explanation is perfect for the current time calculation.

 

However, I'm not sure that in the following formula there is any influence of the atmosphere on Earth - 4.5 By ago. This formula had been used to proof the short cool down period on Earth.

 

 

 

I am not sure you understood SwansonT's point about temperature dependence. In Kelvin the loss of heat is proportional to the FOURTH power of the temperature. You cannot take the entire change in T and the entire time and just average.

 

http://www.wolframalpha.com/input/?i=plot+y%3Dx%5E4+0+to+6500

 

Here is a graph of y=x^4 from 0 to 6500. This vaguely approximates the heat loss - you can use it to understand the ratio of different rates of heat loss (y) for different temperatures (very very roughly) You will note that from about 0-1000 on the x axis you cannot even see the line it is so close to zero on the y axis

 

In any case, do we know the real atmosphere on Earth - 4.5 By ago? Did we use it in our calculation?

Please let me know if I have missed something.

[Robittybob1]

 

Thanks

 

That explanation is perfect for the current time calculation.

 

However, I'm not sure that in the following formula there is any influence of the atmosphere on Earth - 4.5 By ago. This formula had been used to proof the short cool down period on Earth.

 

 

 

In any case, do we know the real atmosphere on Earth - 4.5 By ago? Did we use it in our calculation?

Please let me know if I have missed something.

You can't use the ideal black body radiation formula in cases like this. I have a feeling you would have to consider the temperature of the upper atmosphere of Venus and apply the formula to that. It definitely doesn't relate to the inner core temperatures.

 

 

Stefan–Boltzmann law[edit]

The Stefan–Boltzmann law states that the power emitted per unit area of the surface of a black body is directly proportional to the fourth power of its absolute temperature:

Even then you will be hard pressed to say the planet's atmosphere is a "black body".

[hypervalent_iodine]

!

Moderator Note

Moved to Speculations.

[swansont]

You can't use the ideal black body radiation formula in cases like this. I have a feeling you would have to consider the temperature of the upper atmosphere of Venus and apply the formula to that.

Even then you will be hard pressed to say the planet's atmosphere is a "black body".

 

The S-B law doesn't require an ideal blackbody. The equation includes the emissivity, which is 1 for an ideal blackbody, but the fact that it's in the equation as a variable means you don't have to assume it's 1.

 

 

It definitely doesn't relate to the inner core temperatures.

Good thing nobody has suggested using it in that way.

[Robittybob1]

 

 

 

The S-B law doesn't require an ideal blackbody. The equation includes the emissivity, which is 1 for an ideal blackbody, but the fact that it's in the equation as a variable means you don't have to assume it's 1.

 

 

 

Good thing nobody has suggested using it in that way.

6500 degrees - sounds like core temp Google for "Inner Core Temperature"

 

 

6,000 Degrees Celsius

Earth's Core Temperature A Hellish 6,000 Degrees Celsius, New Study Confirms. A new experiment on the temperature of Earth's core concludes that it's a hellish 6,000 degrees Celsius (10,832 F), a solid 1,000 C (1,832 F) hotter than previously believed when the last temperature model was run 20 years ago.Apr 26, 2013

Really, I was just wondering what surface and what temperature they would using, if they were going to use the Stefan Boltzmann formula?

[swansont]

6500 degrees - sounds like core temp Google for "Inner Core Temperature"

 

Also sounds like temperatures being used for a molten surface of a planet from reading this thread.

[David Levy]

 

Also sounds like temperatures being used for a molten surface of a planet from reading this thread.

 

 

 

So far I didn't get an answer to my following question:

Based on T4 formula, scientists had proved that the Earth could potentially be cooled down from the 6000 to 32 in about 30 My.

However, did the scientists add to this formula the impact of the following factors:

-Atmosphere on Earth

-Crust heat conductance

-Sun radiation

Edited March 28, 2015 by David Levy

[swansont]

 

 

 

So far I didn't get an answer to my following question:

Based on T4 formula, scientists had proved that the Earth could potentially be cooled down from the 6000 to 32 in about 30 My.

However, did the scientists add to this formula the impact of the following factors:

-Atmosphere on Earth

-Crust heat conductance

-Sun radiation

 

What effort have you put forth in finding the answers? You were given a link to a well-referenced article way back in post #2 — have you read G Brent Dalrymple's book, The Age of the Earth? As I recall, he goes through a number of different historical estimates.

[Robittybob1]

 

Also sounds like temperatures being used for a molten surface of a planet from reading this thread.

So according to those wild estimations were the core temperatures 6,000 degrees above the surface temperatures too as it is today? If the core temperatures were as high as this the current rate of cooling of 100 degrees per billion years seems rather an underestimate.

I had always thought that previously the core could be around 500 degrees hotter than today, not the thousands of degrees that would be likely if the surface temperatures ever got that high.

http://en.wikipedia.org/wiki/Inner_core#Dynamics

 

The Earth's inner core is thought to be slowly growing as the liquid outer core at the boundary with the inner core cools and solidifies due to the gradual cooling of the Earth's interior (about 100 degrees Celsius per billion years).

And Venus certainly isn't hot enough the keep it molten. Compared to the early (molten) Earth, both planets are at pretty much the same temperature.

 

David, just come out with it. What is your agenda here? Some sort of creationism? Or that the world must be infinitely old? Or just a general dislike of science?

Well what is your estimate of the core temperatures of Venus then? If it is molten like the Earth and Moon is why is there not a magnetic field?

Edited March 28, 2015 by Robittybob1

[swansont]

So according to those wild estimations were the core temperatures 6,000 degrees above the surface temperatures too as it is today?

Probably not. Nobody here has brought up core temperatures except you. It's not what we're discussing.