Earth was almost flat disc - new Moon theory

[kerbiloid]

Afaik, the estimation is 6 hours, and this corresponds exactly to the "proto-Moon on the Roche limit" case.
And this argues in favour of the hypothesis that the proto-Moon (aka "Theia") has not collided with Earth, but been captured into a very eccentric orbit (very soon turned into circular LEO at 6000 km height), and been destroyed at the Roche limit distance, being at 6000 km from the Earth.
And the modern Moon is the outer tidal hump of the proto-Moon which survived and stayed in orbit, being above the limit.

The proto-Moon has been completely tidally melted, its heavy core passed through the to-the-Earth-side tidal hump and splashed out, crashing the rest.
In this hypothesis the proto-Moon newborn liquid core and most part of its mantle formed a rocky-iron ring around the Earth and quickly rained onto its equator, dissolving in the Earth matter.
Al this drama took several tens thousands years.

The Earth was never totally melted (the proto-Moon energy is too low for that), but it had a melted equatorial belt, and its internal gravitational differentiation has been forced for many times.
So the core has separated in early days (rather than the Venusian one), and the mantle with the original crust have been mixed, so no original rocks stay intact.

As the lunar matter has fallen onto the Earth before the Earth core full separation, it has been totally reworked and mixed with the proto-Earth one, so is undistinguishable.

Also this explains the Earth fast rotation and equator tilt, as well as its fast internal melting and the core formation better that "Crash! Bang!" hypothesis.
(All of that due to the enormous tidal effects from the proto-Moon in low orbit with ~23.5° inclication).

So, initially the Moon has appeared in the ~23.5° inclined orbit, but passing away it approaches to the ecliptic plane, and currently its inclination is just 5°.
While the Earth equator stays 23.5° tilted.

Edited March 31, 2019 by kerbiloid

[Green Baron]

From the links upthread, the capture hypothesis (of an object that originated elsewhere in the protoplanetary disk) was dropped in the 80s in favour of the collision hypothesis because of two reasons: first, the dynamics for the capture are difficult to explain, the moon is simply too massive and would have been too fast to be captured by the earth without additional braking at the right time to enter an orbit. Second, isotopic composition (here: stable oxygen isotopes) suggest a common origin, from the same mass aggregation in that disk. apart from that, it lacks a core that objects of its size should have.

The exact dynamics of the today favoured impact, if it was a glancing blow or a head on impact, if the material was completely vapourized in the event or not (that should actually be testable from the lunar minerals we have, was that done already ?), are in discussion. If you guys like, try to find info on the mineral phases of and conditions that formed the lunar minerals. Probably a lot of shock transformation from impacts.

Just recently a paper was published (linked in the Random Science Facts thread i believe) that found a Zirkon in one of the moons samples with a clear signature from earth. The sample actually pushed the earth's age farther back than all the rock samples from earth itself. That little chip would then be an argument against the forming of the moon from a completely vapourized cloud.

Would ... could ... should .. i should do something productive now :-) Haven't i said "i am out"

Edited March 31, 2019 by Green Baron

[kerbiloid]

45 minutes ago, Green Baron said:

Second, isotopic composition (here: stable oxygen isotopes) suggest a common origin, from the same mass aggregation in that disk. apart from that, it lacks a core that objects of its size should have.

And this means exactly that the Earth and the proto-Moon have appeared at the same distance from the Sun, so from the same cloud.
So, the proto-Moon (or "Theia") from, say, L point, migrated close to the Earth along the close heliocentric orbit, with low relative speed. 
And this is appropriate for both collision and capture hypotheses.
So, this argument is not an argument at all.

45 minutes ago, Green Baron said:

the dynamics for the capture are difficult to explain

while the dynamics of collision is greatly explained with a computer animation and a fancy name.

Afair, the chemical composition features match exactly the "capture-and-melt" hypothesis, while the angular momentum of Earth-Moon system exactly matches the Moon-at-the-Roche-limit case.

45 minutes ago, Green Baron said:

the capture hypothesis (of an object that originated elsewhere in the protoplanetary disk)

Not "elsewhere", but at the same place as the beloved "Theia".

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was dropped in the 80s

My gawd, it's almost in paleolithic times.

P.S.
It's rather strange.
Say, I absolutely don't care if the proto-Moon has collided or captured. I'm ready to get any case, and will be happy with it. It doesn't effect my money.
I just quote the hypothesis read in a thick book with a lot of numbers, formulas, and diagrams, written by a professional, not by me. And it just looks very convincing for me, as the whole book perfectly explains almost all phases of the Earth and Moon further evolution..
But so much emotional expression is caused, like somebody saw the Moon collision personally...

Edited March 31, 2019 by kerbiloid

[Green Baron]

Sorry, your sarcasm makes it difficult to tell the info from the jokes.

30 minutes ago, kerbiloid said:

And this means exactly that the Earth and the proto-Moon have appeared at the same distance from the Sun, so from the same cloud.
So, the proto-Moon (or "Theia") from, say, L point, migrated close to the Earth along the close heliocentric orbit, with low relative speed. 

Nothing L point, no migration. We are under orbital mechanics. Things in the L point can not collide with one of the bodies because they are in resonance. It simply means that the moon is formed from earth's crust with possible mixed stuff from another body. And it did so in the first 10s of millions of years.

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And this is appropriate for both collision and capture hypotheses.

No capture. Capture doesn't work.

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while the dynamics of collision is greatly explained with a computer animation.

It is to the best possible degree under current knowledge, yes. And it explains the high angular momentum of the earth moon system as well, as one can read up.

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Afair, the chemical composition features match exactly the "capture-and-melt" hypothesis, while the angular momentum of Earth-Moon system exactly matches the Moon-at-the-Roche-limit case.

If you mean by "chemical features" the slight differences in isotopic composition, that's the catch for impact thing and still needs further explanation.

 

Edited March 31, 2019 by Green Baron

[kerbiloid]

3 minutes ago, Green Baron said:

Things in the L point can not collide with one of the bodies because they are in resonance.

While they are. Here, in real world, the bodies migrate, and the L-point is not a boolean "here/there".
The whole "Theia" hypothesis began from the originally-L-point body migration.

11 minutes ago, Green Baron said:

No capture. Capture doesn't work.

I trust the word of a gentleman.

[Green Baron]

1 hour ago, kerbiloid said:

While they are. Here, in real world, the bodies migrate, and the L-point is not a boolean "here/there".
The whole "Theia" hypothesis began from the originally-L-point body migration.

Possible misunderstanding between us here ?

An object smaller than the moon could have existed in an earth-moon Lagrange point after the collision, migrated over a few hundred million years through instabilities caused by other bodies around and collided with the moon and created the maria (very hypothetical, they may be just basaltic flows caused by density differences or smaller impacts). But "Theia" did not originate in an earth-sun Lagrange and migrated towards earth. It was probably just one of quite a few bodies of that size in the first 10s of millions of years that happened to cross earth's path. If the collision happened as hypothesized.

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I trust the word of a gentleman.

I simply take my info from the publications i find on the matter and deem reasonable.

 

Edit: unsure if the above is a valid thought at all. Maybe just nonsense so stroke it out.

An impact simulation:

https://www.sciencedirect.com/science/article/abs/pii/S0019103503002999

with peep show:

https://sservi.nasa.gov/articles/evidence-for-moon-forming-impact-found-inside-meteorites/

 

Edited March 31, 2019 by Green Baron

[Rakaydos]

11 hours ago, Green Baron said:

Possible misunderstanding between us here ?

An object smaller than the moon could have existed in an earth-moon Lagrange point after the collision, migrated over a few hundred million years through instabilities caused by other bodies around and collided with the moon and created the maria (very hypothetical, they may be just basaltic flows caused by density differences or smaller impacts). But "Theia" did not originate in an earth-sun Lagrange and migrated towards earth. It was probably just one of quite a few bodies of that size in the first 10s of millions of years that happened to cross earth's path. If the collision happened as hypothesized.

Not an "Earth sun lagrange" but a mutual harmonic relationship.

As a mass began to concentrate i the protoplasmic disk, the lagranges began to form as well. But there's enough mass left in the disk to collapse additional objects, particularly in the relatively stale regions near the lagranges. But if they're too massive compared to the primary, these masses will have their own lagranges, and destabilize the whole system, resulting in planetary collisions and slingshots launching rogue planets into all kinds of crazy orbits.

[Starstruck69]

On 3/29/2019 at 8:45 PM, Cassel said:

It all came from the assumptions that the rocks are actually from the moon and that the whole moon has the same composition?
At the same time we have only one sample of these rocks? So why do you treat such research and these hypotheses seriously?
We should wait for more samples from other places on the moon before we start making hypotheses about collisions that did not happen.
 

This i totally agree with. We have but a mere snippet of geological data from the moon. 

If i were to take a sample from the cotswolds would we assume that the rest of the uk was on limestone?  If we did we all know that this would be misleading and incorrect. Who's to say that other areas will be the same. Untill we sample and test we will never be sure.

[Green Baron]

Guys, if you have followed the links upthread and read what others wrote here you should have understood that this sort of uneducated critique and the "we know nothing" attitude, leaves a bad taste, don't you think ?

People who work on the matter are actually taking not only the obvious differences between earth and moon in account, but also the tiny bits that makes them distinguish between for example material that condensed out of a cloud or formed under certain pressure/temperature regimes, where exposed to impact shock or radiation, measure the isotopic composition, be it stable or unstable isotopes, and draw conclusions about origin and age. Existing uncertainties are taken into account and the resulting open questions left over for future work. Which makes science incredibly thrilling :-)

You could easily read up and understand why samples from the moon's surface tell much more about the moon's overall composition than the same from an earthly stratigraphic unit.

Edited April 1, 2019 by Green Baron

[Cassel]

2 hours ago, Green Baron said:

Guys, if you have followed the links upthread and read what others wrote here you should have understood that this sort of uneducated critique and the "we know nothing" attitude, leaves a bad taste, don't you think ?

People who work on the matter are actually taking not only the obvious differences between earth and moon in account, but also the tiny bits that makes them distinguish between for example material that condensed out of a cloud or formed under certain pressure/temperature regimes, where exposed to impact shock or radiation, measure the isotopic composition, be it stable or unstable isotopes, and draw conclusions about origin and age. Existing uncertainties are taken into account and the resulting open questions left over for future work. Which makes science incredibly thrilling :-)

You could easily read up and understand why samples from the moon's surface tell much more about the moon's overall composition than the same from an earthly stratigraphic unit.

Maybe you should understand that what you are referring to is not knowledge, but suppositions? So saying that we do not know X is certainly more scientific than the fanatical defense of some hypothesis based on one sample of rocks and few assumptions.

On 3/30/2019 at 9:22 AM, kerbiloid said:

Take a look at the 'steroid belt.

That's what Jupiter's orbit looks like.

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This.

  Reveal hidden contents

(but without a shotgun

)

 

[snip]

Compared to Jupiter they're microscopic. Size matters.

What does it matter? Jupiter is the largest object, and now gradually captures smaller ones. Isn't this what the clearing of the orbit is about?

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It looks like an abortion material of a planet. Not enough to make one.

Nobody claims that it must be the second Jupiter. But maybe Ceres can be built from it or smaller body, it doesn't matter, how large it will be. Fact is there is material that can form into planet.

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Probably we can see the remains of one every night.

Or the result of clearing the orbits of other planets.

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Originally the Moon was much closer to us. Getting farther and farther, it has smashed and consumed all debries and probably original satellites.
Nowadays L points are far beyond the original Moon orbit.

Evidence?

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No. All is gone.

 

So we can come up with any explanation and that most people believe will be true.

Edited April 1, 2019 by Cassel

[Cassel]

I see that no noticed to the fact that if a fast spinning hot planet can produce the moon. The fast spinning star (or almost star) should be able to create a planet that will be pushed away from this star. Soon someone will probably modify this synestia hypothesis and remove the necessity of two collisions with Earth, and instead write that the Earth and the moon were created directly from the material from the forming star.

[Rakaydos]

23 minutes ago, Cassel said:

I see that no noticed to the fact that if a fast spinning hot planet can produce the moon. The fast spinning star (or almost star) should be able to create a planet that will be pushed away from this star. Soon someone will probably modify this synestia hypothesis and remove the necessity of two collisions with Earth, and instead write that the Earth and the moon were created directly from the material from the forming star.

That's called an Accretion disk. It already is the leading theory of stellar formation.

[Cassel]

16 minutes ago, Rakaydos said:

That's called an Accretion disk. It already is the leading theory of stellar formation.

What is the difference between Accretion disk and Synestia?

[Rakaydos]

15 minutes ago, Cassel said:

What is the difference between Accretion disk and Synestia?

A Synestia is formed by the energy of a bi-planetary impact vaporizing rock but staying roughly planet-shaped. ("roughly" includes high spin that distends but doesn't disassociate the equator with the main body) An accretion disk is what you get when a field of particles collapses gravitationally and tidal effects induce a spin as they fall in, creating a rotating mass that hasn't solidified yet.

If two stars or gas giants tried making a synestia, the result is usually a Nova or a star, depending.

Edited April 1, 2019 by Rakaydos

[Green Baron]

A synestia is a (hypothetical) planetary body, a doughnut shaped cloud of vapour and molten rock resulting from a high energetic impact of two solid planetary bodies. A synestia has not been observed yet.

If i am not mistaken, an accretion disk forms around massive (e. g. white dwarfs) or supermassive bodies (neutron stars, black holes, active galactic nuclei) that have one or more companions from whom they draw material, or in the case of active galactic nuclei, from objects that come too close while orbiting. Accretion disks have been observed, even Sag A* while digesting a cloud, and there is more to expect in the near future (gnawing fingernails since more than a year now for a @!§ photo from Sagittarius A*).

A protoplanetary disk is a cloud of interstellar gases (H, He) and small dust particles, leftover from Supernovae or just clouds of interstellar gases, that start to contract because of an external impulse, conserving its impulse and momentum in the bodies that form inside of it. Several protoplanetary disks have been observed by now, especially by the VLT. Just recently the case of a binary star casting its rotating shadows on the disk surrounding it was published. Beautiful. Imagine we had half sun :-)

Edited April 1, 2019 by Green Baron

[Starstruck69]

On 4/1/2019 at 2:49 PM, Green Baron said:

Guys, if you have followed the links upthread and read what others wrote here you should have understood that this sort of uneducated critique and the "we know nothing" attitude, leaves a bad taste, don't you think ?

People who work on the matter are actually taking not only the obvious differences between earth and moon in account, but also the tiny bits that makes them distinguish between for example material that condensed out of a cloud or formed under certain pressure/temperature regimes, where exposed to impact shock or radiation, measure the isotopic composition, be it stable or unstable isotopes, and draw conclusions about origin and age. Existing uncertainties are taken into account and the resulting open questions left over for future work. Which makes science incredibly thrilling :-)

You could easily read up and understand why samples from the moon's surface tell much more about the moon's overall composition than the same from an earthly stratigraphic unit.

Baron are you suggesting that we know the geology of the moon after 1 sample? Wow i didn't know we could do that, i had better get reading i guess. Apologies for my uneducated critique

[Green Baron]

That "only 1 sample" thing is a little inaccurate. We have much more than 1 sample. There is:

- all in all ~400kg of samples from the six Apollo landing sites

- a few samples from Soviet landers

- some meteorites from the moon, others from around the solar system

- telescopes

- measurements from orbiting spacecrafts

- a good grasp of the history of the solar- and the earth moon system

- a bulk of geo-* data from earth

 

All in all enough to build a rough geological timescale of the moon as a whole, which is much simpler than the earth's also because the moon does not have many of the processes that form and change earth, like mantle convection, tectonics, an atmopshere, biosphere, hydrosphere, ...

 

Edited April 5, 2019 by Green Baron

[Starstruck69]

3 hours ago, Green Baron said:

That "only 1 sample" thing is a little inaccurate. We have much more than 1 sample. There is:

- all in all ~400kg of samples from the six Apollo landing sites

- a few samples from Soviet landers

- some meteorites from the moon, others from around the solar system

- telescopes

- measurements from orbiting spacecrafts

- a good grasp of the history of the solar- and the earth moon system

- a bulk of geo-* data from earth

 

All in all enough to build a rough geological timescale of the moon as a whole, which is much simpler than the earth's also because the moon does not have many of the processes that form and change earth, like mantle convection, tectonics, an atmopshere, biosphere, hydrosphere, ...

 

You make some great points Baron i just don't think that we can turn the page just yet. I would like to see a more thorough analysis but as always funding/prioritising always gets in the way, also would i prioritise that over a mars/deep solar mission? Probably not. 

Did the russians share the data from the samples taken with the west? I do remember there was some controversy but can't confirm the exact details. Are you referring to Luna 20?

[Green Baron]

Sure, a whole lot of questions about the moon's geology are open, but quite a lot is known as well. I was just defending the documented knowledge about the moon and the hypotheses derived from the evidence at hand against the "1 sample" claim.

Without strolling too far for it costs time, please believe me that a geologist does not need samples for comparison of everything. A basalt, the most common "stuff" on Moon and Mars, is physically and chemically a pretty simple rock. Sediments are complicated !

:-)

[Starstruck69]

49 minutes ago, Green Baron said:

Without strolling too far for it costs time,

Then stroll no more. Thankyou for your time.