Question Earth Moon Origin

[Inmymind]

Supposing angular momentum presents problems if the Earth and Moon formed alongside each other, what are those issues, and how does the impact hypothesis provide a more coherent answer to these?

 

[billslugg]

I am speculating, because at the time I was just a little baby, but I would assume 4.6 billion years ago there was insufficient angular momentum in any one knot of dust in the protoplanetary disc to create an Earth/Moon system. The disc itself has lots of angular momentum but each knot has little of its own.

In the impact scenario, an off center hit gives all that is needed.

 

[Inmymind]

I am speculating, because at the time I was just a little baby, but I would assume 4.6 billion years ago there was insufficient angular momentum in any one knot of dust in the protoplanetary disc to create an Earth/Moon system. The disc itself has lots of angular momentum but each knot has little of its own.

In the impact scenario, an off center hit gives all that is needed.

I'm trying to get away from the assumptions to seek the science behind.

 

[Inmymind]

I am speculating, because at the time I was just a little baby, but I would assume 4.6 billion years ago there was insufficient angular momentum in any one knot of dust in the protoplanetary disc to create an Earth/Moon system. The disc itself has lots of angular momentum but each knot has little of its own.

In the impact scenario, an off center hit gives all that is needed.

I am also speculating. Suppose the Earth started to form in its own vortex of cooling constituents and the Moon started to form 100m years or so later, in its own vortex of slightly different cooling constituents, ie not from the same knot of dust as you term it. Would that satisfy the angular momentum problem?

 

[billslugg]

In order for the Moon to have originated somewhere else in the Solar Nebula and then have it go into orbit around the Earth requires the Moon to interact with a third body to redirect it to Earth and then it requires another interaction with a fourth body to settle it into orbit. "Too chancy". The impact hypothesis avoids all those problems.

 

[Inmymind]

In order for the Moon to have originated somewhere else in the Solar Nebula and then have it go into orbit around the Earth requires the Moon to interact with a third body to redirect it to Earth and then it requires another interaction with a fourth body to settle it into orbit. "Too chancy". The impact hypothesis avoids all those problems.

That is not my premise.

The Earth got to be the Earth by consuming/absorbing/sweeping up, some of what was within its reach, chemistry/physics/temperatures permitting.

Maybe the Moon was next in line for lunch, but the one that got away, by the skin of its... skin.

 

[billslugg]

Sorry, no theory can account for the composition and the angular momentum of the Earth/Moon system other than an impact hypothesis.

 

[billslugg]

So how in scientific terms does the impact hypothesis provide a more coherent answer to these?

The impact hypothesis has a Mar's size planet hitting the proto Earth just enough off center to leave the iron core of the proto Earth intact. This is why the Moon lacks iron. The off center hit also generates the needed angular momentum.

 

[Inmymind]

The impact hypothesis has a Mar's size planet hitting the proto Earth just enough off center to leave the iron core of the proto Earth intact. This is why the Moon lacks iron. The off center hit also generates the needed angular momentum.

The impact hypothesis has a Mar's size planet hitting the proto Earth just enough off center to leave the iron core of the proto Earth intact. This is why the Moon lacks iron. The off center hit also generates the needed angular momentum.

But where is the science and maths for this, assertion is no good, impact theory is being challenged in terms of isotopic compositions not aligning. What is the maths that the impact theory fulfils such that angular momentum is satisfied?

 

[billslugg]

Sorry, can't help you there. I don't know much about the mathematical details of Lunar origin, all I know is what the current explanation is.
For a good discussion of the models, see the Wiki article. It discusses all the current models and mentions some of the isotopic oddities.

Origin of the Moon - Wikipedia

en.wikipedia.org

 

[Harry Costas]

Wikipedia is wrong.
The collision theory falls apart when we look at the moon's structure. Suggesting the same origin of the moon taking place at the same time the Earth was forming.

 

[billslugg]

One problem is the Moon's iron core is only 1% and Earth's is 13%. If they formed from separate parts of the same cloud they would have the same iron amounts.
Second problem is that formation together fails to get the Moon into orbit. Where does the angular momentum come from unless it gets hit by an interloper?

 

[Adel]

Knowing the scientific and geological explanation for the existence of the lunar seas is considered a window to knowing the origin of the moon, the earth, and the solar system in general, and this is what the theory I have reached will show. The theory that will explain how the lunar seas were formed based on scientific evidence that proves the validity of the theory

 

[COLGeek]

Knowing the scientific and geological explanation for the existence of the lunar seas is considered a window to knowing the origin of the moon, the earth, and the solar system in general, and this is what the theory I have reached will show. The theory that will explain how the lunar seas were formed based on scientific evidence that proves the validity of the theory

When and where will this theory be published?

 

[Harry Costas]

Science is a funny field
Many theories that seem logical today seem not so logical the next day.
Yes!
Undisputed evidence is the way to go

 

[Inmymind]

Wikipedia is wrong.
The collision theory falls apart when we look at the moon's structure. Suggesting the same origin of the moon taking place at the same time the Earth was forming.

It seems to be looking that way imo , and then there is the massive amount of water elements trapped in Earth's rocks.

 

[billslugg]

The Moon has an iron core 1% of its mass. The Earth has an iron core 13% of its mass. How did they get so different? Also, what put the Moon into orbit? No amount of mutual coalescence can explain these facts.

 

[Inmymind]

One problem is the Moon's iron core is only 1% and Earth's is 13%. If they formed from separate parts of the same cloud they would have the same iron amounts.
Second problem is that formation together fails to get the Moon into orbit. Where does the angular momentum come from unless it gets hit by an interloper?

Sorry, can't help you there. I don't know much about the mathematical details of Lunar origin, all I know is what the current explanation is.
For a good discussion of the models, see the Wiki article. It discusses all the current models and mentions some of the isotopic oddities.

Origin of the Moon - Wikipedia

en.wikipedia.org

Thank you Bill, the thumbs up was more for an acknowledgement that no progress had been made wrt the angular momentum problem, rather than approval of the wiki link.

Wrt "Second problem is that formation together fails to get the Moon into orbit. Where does the angular momentum come from unless it gets hit by an interloper?"

I am not good on angular momentum, so I'll throw this out there. Suppose you have a full swimming pool containing one petits pois and one large beach ball of similar density, and you pull the plug out. What would be the angular momentum of each approaching the moment before they came together as the last of the water drained away? ie might this be analogous to the Earth/Moon scenario?

 

[billslugg]

If you put balloons on the surface of the pool water and pull the plug they will simply gather together in the center. If they pool is big enough, say hundreds of miles across, and is not located on the equator, then the Coriolis force will result in the bunch of balloons rotating. The amount of angular momentum of any such gathering is proportional to its area. A small knot within a large assemblage will have only a tiny angular momentum, not sufficient to explain the Moon's. This pretty much rules out coformation from dust knots. It leaves collision or capture. Collision is far more likely as there are many spots on Earth where a good hit would make a Moon. There are not a lot of spots the Moon and a third body could do a dance resulting in the capture of the Moon. Collision requires two bodies, somewhat rare. Capture requires three bodies, extremely rare. Also, the Moon crust and Earth crust are identical. This rules out capture. Collision is the only one that can account for all the data. There are still some nagging details they can't figure out.

 

[Inmymind]

Thank you Bill, the thumbs up was more for an acknowledgement that no progress had been made wrt the angular momentum problem, rather than approval of the wiki link.

Wrt "Second problem is that formation together fails to get the Moon into orbit. Where does the angular momentum come from unless it gets hit by an interloper?"

I am not good on angular momentum, so I'll throw this out there. Suppose you have a full swimming pool containing one petits pois and one large beach ball of similar density, and you pull the plug out. What would be the angular momentum of each approaching the moment before they came together as the last of the water drained away? ie might this be analogous to the Earth/Moon scenario?

"One problem is the Moon's iron core is only 1% and Earth's is 13%. If they formed from separate parts of the same cloud they would have the same iron amounts"

You are assuming that the cloud was uniform and they started to form at the same time.

 

[Inmymind]

If you put balloons on the surface of the pool water and pull the plug they will simply gather together in the center. If they pool is big enough, say hundreds of miles across, and is not located on the equator, then the Coriolis force is will result in the bunch of balloons rotating. The amount of angular momentum of any such gathering is proportional to its area. A small knot within a large assemblage will have only a tiny angular momentum, not sufficient to explain the Moon's. This pretty much rules out coformation from dust knots. It leaves collision or capture. Collision is far more likely as there are many spots on Earth where a good hit would make a Moon. There are not a lot of spots the Moon and a third body could do a dance resulting in the capture of the Moon. Collision requires two bodies, somewhat rare. Capture requires three bodies, extremely rare. Also, the Moon crust and Earth crust are identical. This rules out capture. Collision is the only one that can account for all the data. There are still some nagging details they can't figure out.

My analogy is for immersed, not floating, objects - does that change anything?

 

[billslugg]

No, it doesn't help. No system can make its own angular momentum. It is born with whatever it has. In order to increase angular momentum, there must be an injection of energy from outside the system. You cannot make yourself rotate without someone pushing on you. You can clump at a collection point without any outside influence, but not set yourself spinning.
Note that the Solar nebula had lots of angular momentum, when each planet consolidated it ended up rotating the same as the Solar System.
Each planet could produce moons that also rotated around it, using the angular momentum in its immediate area. The problem is there is not enough angular momentum in a knot to produce an Earth/Moon type system.