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