Earth - What is the real age?

[imatfaal]

So what part of "cooling time is on the order of accretion time (100my) or longer" is inconsistent with the cooling time being around 100 million years?

 

David Levy - that would be OK as long as you are both talking of the Moon, but not if one is talking about the Moon and the other about the Earth.

The sentence does not specify what body/bodies it is being discussed.

 

Yes, it is the Moon

....

 

 

Nope.

 

In pg 181 it is stated:

...To summarize, substantial bodies (1M or even 0.5 M) must be extensively partially molten in order to lose heat efficiently, and would be even more molten if they failed to lose heat efficiently. The cooling time is on the order of accretion time (100my) or longer.

 

1. This is a misquote - you must get quotes exact or do not put them in quotation marks. At best what you have done is very very sloppy and at worst could be viewed as deliberately deceptive.

2. The symbol that follows the Ms in "(and a mass of order 1M or even 0.5M qualifies)" is the symbol for Mars!

 

 

Nope - again

 

..."From the number mentioned previously, it is evident that an incoming mass of order 1 M has sufficient energy to melt all of Earth".

 

1. Again not accurately transcribed - although just a typo this time

2. "it is evident that an incoming mass of order 1 M" - the symbol that follows the M is that of Mars again.

[Robittybob1]

Mars! Now that finally makes sense.

[swansont]

It's also not entirely clear what level of solidification they are discussing using that time scale. Nobody is claiming the earth cooled to the point of being a solid; that would be ridiculous. The book even confirms the use of Stefan-Boltzaman, and how efficient the cooling would be for a molten system. They also point out that the interior will not cool efficiently once the exterior has solidified, but then, that's not the issue we had been discussing.

 

IOW, the material does not call into question the analysis that's been presented here.

[Robittybob1]

It's also not entirely clear what level of solidification they are discussing using that time scale. Nobody is claiming the earth cooled to the point of being a solid; that would be ridiculous. The book even confirms the use of Stefan-Boltzaman, and how efficient the cooling would be for a molten system. They also point out that the interior will not cool efficiently once the exterior has solidified, but then, that's not the issue we had been discussing.

 

IOW, the material does not call into question the analysis that's been presented here.

Well the Earth isn't solid even today, and apparently neither is the Moon. I wouldn't be surprised if Venus wasn't liquified in the center as well (opinion only). Mars with its cold surface, small volume and little atmosphere cooled and "froze" the core and hence lost its magnetic field.

So "cooling" must be related to surface cooling only, and having the surface cool enough for living organisms to survive. Unless there was some water to cool things by evaporation or conduction/convection the early earth would have been a very dangerous place to live on (volcanoes, mud pools, geysers).

[swansont]

Well the Earth isn't solid even today

Hence it would be ridiculous to think that the scenario is that it's completely solid.

 

The question is how thick the crust is. The reason that heat transfer becomes less efficient with the crust is that it insulates - it's significantly cooler on the outside.

[David Levy]

1. This is a misquote - you must get quotes exact or do not put them in quotation marks. At best what you have done is very very sloppy and at worst could be viewed as deliberately deceptive.

2. The symbol that follows the Ms in "(and a mass of order 1M or even 0.5M qualifies)" is the symbol for Mars!

 

Well, in this entire article I couldn't find even one word about Mars. The title is - Thermal Aspects of Lunar origin by giant impact. They also claim - Our goal here is to assess whether the moon we know is compatible with the Moon that might form following a giant impact. Therefore, I would expect that they had intention to discuss about the Moon' heat dissipation. Therefore, it might be some kind of a typo error.

However, let's assume that it is Mars.

In any case, Earth mass is bigger than Mars by about 10 times. Therefore, if 100 My is needed for Mars than 1,000 My is needed for Earth to cool down.

It is stated: The cooling time is on the order of accretion time (100my) or longer.

What is the meaning of longer? Is it 10, 100, or 1,000 My?

It seems that they are not fully sure about the total requested time for heat dissipation under the Crust heat conductance factor. The minimum time is 100 My, but the maximum is not defined.

To summarize;

This article gives a solid evidence that by taking in account just one factor, the requested cooling time (for Mars) is at least 100 My. This is an indication that the cooling time for Earth under the Crust heat conductance factor could be more than 1,000 My. By adding the other factors as Atmosphere and sun radiation increase (The Earth was closer to the sun in the past), the cooling time for the Earth must be even longer.

This is a waking call for the science community to verify those key factors. It is needed to make more realistic simulation in order to understand the real age of Earth. The current assumption that only 30 My (or even 100 My) is needed for the Earth as cooling time is absolutly incorrect!

Edited March 30, 2015 by David Levy

[Strange]

The current assumption that only 30 My (or even 100 My) is needed for the Earth as cooling time is absolutly incorrect!

 

Please show the detailed analysis (including the effects of atmosphere, if you consider it important) that supports this conclusion.

[swansont]

 

They also claim - Our goal here is to assess whether the moon we know is compatible with the Moon that might form following a giant impact. Therefore, I would expect that they had intention to discuss about the Moon' heat dissipation. Therefore, it might be some kind of a typo error.[/size]

Part of their discussion is whether the moon was hot when it formed, or not, and that relies on the state of the earth. They are giving a cutoff for the cooling behavior, and arguing that the earth was mostly molten at the time of impact. Since that's though to have happened soon after the solar system formed, that's not unreasonable.

 

You can't just assume typo because you want it to agree with you, and you have to actually read the things you cite.

 

However, let's assume that it is Mars.

In any case, Earth mass is bigger than Mars by about 10 times. Therefore, if 100 My is needed for Mars than 1,000 My is needed for Earth to cool down.

Again, what's needed is what they mean by cooling, and once again you have made a linear extrapolation based on absolutely zero science.

 

It is stated: The cooling time is on the order of accretion time (100my) or longer.

What is the meaning of longer? Is it 10, 100, or 1,000 My?

It seems that they are not fully sure about the total requested time for heat dissipation under the Crust heat conductance factor. The minimum time is 100 My, but the maximum is not defined.

To summarize;

This article gives a solid evidence that by taking in account just one factor, the requested cooling time (for Mars) is at least 100 My. This is an indication that the cooling time for Earth under the Crust heat conductance factor could be more than 1,000 My. By adding the other factors as Atmosphere and sun radiation increase (The Earth was closer to the sun in the past), the cooling time for the Earth must be even longer.

This is a waking call for the science community to verify those key factors. It is needed to make more realistic simulation in order to understand the real age of Earth. The current assumption that only 30 My (or even 100 My) is needed for the Earth as cooling time is absolutly incorrect!

The paper is not evidence, the paper presents a model. It is undoubtedly not the only one, and others might not agree. You can't cherry-pick bits of science that you like (and add non-science of your own) and deem it a "waking call" and have anyone take you seriously.

[Robittybob1]

Hence it would be ridiculous to think that the scenario is that it's completely solid.

 

The question is how thick the crust is. The reason that heat transfer becomes less efficient with the crust is that it insulates - it's significantly cooler on the outside.

Is there a really good timeline for the first Gy of Earth's existence?

That article on the Iron Catastrophe said it was 500 My after formation, so I take that to mean the Earth was reasonably solid (maybe partially molten) till the iron poured into the center of the Earth.

When does Theia impact fit around that? Presumably it was after the Iron Catastrophe. It is time for me to do some homework on this.

 

Well this article gives me a clue: http://www.space.com/25322-moon-formation-wild-theories.html

 

While the giant-impact hypothesis continues to be tweaked and refined, it does the best job of explaining the moon's composition and orbit, most scientists say. For example, the theory predicts a small iron core for the moon, since it would have formed primarily from the mantles of the impactor and early Earth (both of which lacked iron, which had already been concentrated deep in the core).

So it was after the Iron Catastrophe according to that!

But because the Moon and Earth rocks date back to an early age they can't have the Moon forming 0.5 Gy after the Earth forms.

 

There seems to be an even newer theory, where two bodies of roughly equal mass collide.

http://www.nasa.gov/topics/solarsystem/features/moon_formation.html

 

 

NASA Lunar Scientists Develop New Theory on Earth and Moon Formation10.30.12

 

Image of moon Click on image for full resolution.

New research funded by NLSI theorizes that our early Earth and moon were perhaps created in a different manner than has previously been believed.

Image credit: NASA New research, funded by the NASA Lunar Science Institute (NLSI), hypothesizes that our early Earth and moon were both created together in a giant collision of two planetary bodies that were each five times the size of Mars.

This new hypothesis about how Earth’s moon formed is challenging the commonly believed “giant impact hypothesis,” which suggests that Earth's moon formed from a colossal impact of a hypothetical planetary embryo, named Theia, with Earth, early in our Solar System's history.

Nothing is easy but with this you get a total blending of the isotopes make the Earth and Moon of similar composition.

Now that sort of Impact would presumably be a total meltdown. Ek = 1/2 * M1 * V1^2 + 1/2 * M2 * V2^2

M1 = M2 approximately.

 

Would the velocities of these two bodies be in similar or opposite directions?

Edited March 31, 2015 by Robittybob1

[swansont]

Is there a really good timeline for the first Gy of Earth's existence?

That article on the Iron Catastrophe said it was 500 My after formation, so I take that to mean the Earth was reasonably solid (maybe partially molten) till the iron poured into the center of the Earth.

When does Theia impact fit around that? Presumably it was after the Iron Catastrophe.

I've read at least one summary that puts it at a few tens of millions of years after the formation of the solar system.

[imatfaal]

Well, in this entire article I couldn't find even one word about Mars. The title is - Thermal Aspects of Lunar origin by giant impact. They also claim - Our goal here is to assess whether the moon we know is compatible with the Moon that might form following a giant impact. .

 

About the 30th word of the article is MARS - did you read the article or just quote mine it?

 

 

The result of the impact was the Moon - but it is clear that the impact was between proto-earth and a wanderer of similar size to earth or mars.

 

Therefore, it might be some kind of a typo error.

However, let's assume that it is Mars.

 

Nonsense - it is Mars.

 

 

On both occassions

 

 

Here is a guide on the Astronomical Symbols of the Planets for you to read before you continue to lecture us

[Robittybob1]

 

About the 30th word of the article is MARS - did you read the article or just quote mine it?

 

still mars.jpg

 

The result of the impact was the Moon - but it is clear that the impact was between proto-earth and a wanderer of similar size to earth or mars.

 

 

Nonsense - it is Mars.

 

mars.jpg

 

On both occassions

 

mars as well.jpg

 

Here is a guide on the Astronomical Symbols of the Planets for you to read before you continue to lecture us

Still seems a bit confusing to me. Why would they be concerned how quickly a Mars sized object cools?

I've read at least one summary that puts it at a few tens of millions of years after the formation of the solar system.

If it happened as early as this then the timeline looks better, for the Iron Catastrophe would precede the Giant Impact. I'll see if there is any reference to support this.

[swansont]

 

If it happened as early as this then the timeline looks better, for the Iron Catastrophe would precede the Giant Impact. I'll see if there is any reference to support this.

 

Um, no. "Tens of millions" is smaller than 500 million.

[Robittybob1]

 

Um, no. "Tens of millions" is smaller than 500 million.

Could you please paraphrase what you are saying? I was thinking if the Iron Catastrophe occurred before the Giant Impact then the events are in the right sequence. Do you disagree with that?

[swansont]

Could you please paraphrase what you are saying? I was thinking if the Iron Catastrophe occurred before the Giant Impact then the events are in the right sequence. Do you disagree with that?

 

Yes. If the impact happened after a few tens of millions of years after formation, that's well before the iron catastrophe at 500 million. This is pretty simple math.

[Robittybob1]

 

Yes. If the impact happened after a few tens of millions of years after formation, that's well before the iron catastrophe at 500 million. This is pretty simple math.

That is the problem. There would be nothing left for the iron catastrophe to do if the Giant impact occurred ahead of it.

 

Somehow we have to get the Iron Catastrophe to occur before the Moon formation.

Otherwise they couldn't say things like this

"For example, the theory predicts a small iron core for the moon, since it would have formed primarily from the mantles of the impactor and early Earth (both of which lacked iron, which had already been concentrated deep in the core)."

 

 

In that analysis the Iron Catastrophe had already occurred before the Giant Impact.

Edited March 31, 2015 by Robittybob1

[pavelcherepan]

That is the problem. There would be nothing left for the iron catastrophe to do if the Giant impact occurred ahead of it.

 

Somehow we have to get the Iron Catastrophe to occur before the Moon formation.

How so? Would there be no iron to sink to the center? Quite the opposite, actually. Proto-Earth gained a lot of iron and heavy metals from the impact with Theia.

[swansont]

That is the problem. There would be nothing left for the iron catastrophe to do if the Giant impact occurred ahead of it.

 

Somehow we have to get the Iron Catastrophe to occur before the Moon formation.

Otherwise they couldn't say things like this

 

In that analysis the Iron Catastrophe had already occurred before the Giant Impact.

 

Why? Would the iron have disappeared?

[pavelcherepan]

In that analysis the Iron Catastrophe had already occurred before the Giant Impact.

Many models do assume that by the time of the impact both Theia and proto-Earth have been partially differentiated with small iron-rich cores in both of those, but the remainder of iron was still spread around the rest of material and in fact Giant Impact would have accelerated density differentiation due to increase of temperatures. It's also generally assumed that IC took a significant period of time, so it might have started before the impact but went on for another half a billion years or so.

[Robittybob1]

 

Why? Would the iron have disappeared?

The concentration of iron in the Mantle would have dropped (being already concentrated in the core). As I understand the GIT the core of the Moon is predominantly from the core of the impactor.

The glancing blow does not rip iron out of the Earth's core, but there is an exchange of Mantle and Crustal components.

I could be wrong about this for I personally prefer the Moon Capture theory but it is not getting the support it needs.

How so? Would there be no iron to sink to the center? Quite the opposite, actually. Proto-Earth gained a lot of iron and heavy metals from the impact with Theia.

True as I found out the other day. The Mars sized planet is around 9 times larger than the Moon, so it basically left 8/9ths of its mass here on Earth if the theory is correct.

Edited March 31, 2015 by Robittybob1

[swansont]

The concentration of iron in the Mantle would have dropped (being already concentrated in the core).

 

Why would it be concentrated in the core after a few tens of millions of years?

[pavelcherepan]

 

The concentration of iron in the Mantle would have dropped (being already concentrated in the core). As I understand the GIT the core of the Moon is predominantly from the core of the impactor.

 

Even now mantle has around 7.5% of Fe by weight, which is of course relatively low compared to overall composition of the Earth (32.1% Fe) but still it's not what you call depleted. So with that in mind what makes you think that in less than 100 my from the formation of the planet the mantle was already low on iron?

[Robittybob1]

 

Why would it be concentrated in the core after a few tens of millions of years?

There seems to be a bit of confusion between my view and quoted views of other people (scientists?). I have never tried to determine when the iron core of the Earth formed so that statement "concentrated in the core after a few tens of millions of years" must have been a quote from another source.

 

Even now mantle has around 7.5% of Fe by weight, which is of course relatively low compared to overall composition of the Earth (32.1% Fe) but still it's not what you call depleted. So with that in mind what makes you think that in less than 100 my from the formation of the planet the mantle was already low on iron?

OK can you heat the material in the Mantle, as it is today, and get liquid iron metal just to separate out of it? That is how I picture the iron catastrophe working.

After the iron has separated and settled in the core then I'd say the "mantle was already low on iron" not before "the Iron Catastrophe" event took place.

I plan to look into the timing of these events soon and see if they can be coordinated for at the moment the timing order seems to be reversed.

If you were a Moon capture theory advocate none of this is that important, for the relative proportions of iron in the Moon and the Earth have another cause altogether.

Edited April 1, 2015 by Robittybob1

[swansont]

There seems to be a bit of confusion between my view and quoted views of other people (scientists?). I have never tried to determine when the iron core of the Earth formed so that statement "concentrated in the core after a few tens of millions of years" must have been a quote from another source.

 

You insisted the iron catastrophe happened before the impact, which happened after a few tens of millions of years, and you did quote a number for the iron catastrophe at 500 mya. Obviously (I hope) the views two are incompatible

[Robittybob1]

 

You insisted the iron catastrophe happened before the impact, which happened after a few tens of millions of years, and you did quote a number for the iron catastrophe at 500 mya. Obviously (I hope) the views two are incompatible

I won't be insisting on anything really for as I have already said I prefer the Moon Capture Theory. But as you have noted there is definitely an inconsistency in the Giant Impact theory for they need the impact to occur "after a few tens of millions of years" but the Iron Catastrophe (IC) appears to occur much later, yet the heating that occurred during the Giant Impact would have immediately set the IC in motion at the very least.

There definitely appears to be something incompatible between the two ideas.