# Earth's Moon
**URL:** https://boards.straightdope.com/t/earths-moon/773478
**Category:** Factual Questions
**Created:** [November 30, 2016, 6:39pm UTC](https://boards.straightdope.com/t/earths-moon/773478 "2016-11-30T18:39:48Z")
**Posts on this page:** 20
**Page:** 2
### Author:  [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)
#### Post date: [December 1, 2016, 1:56am UTC](https://boards.straightdope.com/t/earths-moon/773478/21 "2016-12-01T01:56:00Z")
Just wanted to add a YouTube video of a computer simulation of the collision … this shows how much violence was potentially involved in such a collision … how much mass was torn free … not a thing rocks would survive …
[YouTube](https://www.youtube.com/watch?v=Fwl_JBQtH9o) {0’42"}
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### Author:  [@JKellyMap](https://boards.straightdope.com/u/JKellyMap)
#### Post date: [December 1, 2016, 3:15am UTC](https://boards.straightdope.com/t/earths-moon/773478/22 "2016-12-01T03:15:31Z")
> [@watchwolf49](#):
>
> Just wanted to add a YouTube video of a computer simulation of the collision … this shows how much violence was potentially involved in such a collision … how much mass was torn free … not a thing rocks would survive …
> [YouTube](https://www.youtube.com/watch?v=Fwl_JBQtH9o) {0’42"}
Wow, that’s awesome. It’s like two water balloons being thrown together at high velocity. Then ten minutes of a shaggy dog who just swam across a lake shaking off the water.
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### Author:  [@AK84](https://boards.straightdope.com/u/AK84)
#### Post date: [December 1, 2016, 3:18am UTC](https://boards.straightdope.com/t/earths-moon/773478/23 "2016-12-01T03:18:19Z")
Basically the new hypothesis is a modification of the Impact hypothesis. The original one was that it was a glancing blow, the new one is that both planets were destroyed in the impact and the Earth and the Moon formed from the resulting debris.
Ironically, Darwin’s theory, which was disproved after Apollo, might not have been wrong after all. 😃
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### Author:  [@MrDibble](https://boards.straightdope.com/u/MrDibble)
#### Post date: [December 1, 2016, 4:55am UTC](https://boards.straightdope.com/t/earths-moon/773478/24 "2016-12-01T04:55:21Z")
> [@Darren\_Garrison](#):
>
> Yep, I did it myself. I like playing around with CGI programs, but lack much actual talent at it. Mapping textures to spheres is dead simple, though, so I created to-scale models of all the planets, “official” dwarf planets, and major moons of the solar system. I then used rigid body physics simulation to fill a hollow shell of the Earth. They fit. [Here](https://www.youtube.com/watch?v=g4CTJWtwQqk) is a video I created.
That’s great work.
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [December 1, 2016, 11:30am UTC](https://boards.straightdope.com/t/earths-moon/773478/25 "2016-12-01T11:30:48Z")
> [@Chronos](#):
>
> **Darren Garrison** , you missed at least one dwarf planet, the first of them to be discovered: Ceres. And depending on your standards for “spherical”, one or two other asteroids might qualify, too. Not all of the dwarf planets are in the outer solar system.
No, Ceres is there. It is so small that you might not even see it unless you are running full-screen at 1080p. I didn’t count the second largest asteroid, Vesta, as spherical, but you could still fit Vesta plus every other asteroid in the spaces between the larger objects–they are like dust compared to even a small spherical moon or dwarf planet.
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### Author:  [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)
#### Post date: [December 1, 2016, 11:36am UTC](https://boards.straightdope.com/t/earths-moon/773478/26 "2016-12-01T11:36:57Z")
> [@Darren\_Garrison](#):
>
> Yep, I did it myself. I like playing around with CGI programs, but lack much actual talent at it. Mapping textures to spheres is dead simple, though, so I created to-scale models of all the planets, “official” dwarf planets, and major moons of the solar system. I then used rigid body physics simulation to fill a hollow shell of the Earth. They fit. [Here](https://www.youtube.com/watch?v=g4CTJWtwQqk) is a video I created.
That was awesome, thank you.
---
### Author:  [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)
#### Post date: [December 1, 2016, 1:59pm UTC](https://boards.straightdope.com/t/earths-moon/773478/28 "2016-12-01T13:59:10Z")
The thing that puzzles me about this impact is the relationship between continental crust, oceanic crust, tectonics and the residue of the impact.
Continental crust is quite thick, so much so that the continents are basically the same as they have always been. Whereas oceanic crust is very much thinner, and is subject to subduction and recycling. Basically the continents have been around forever, but the oceans are ephemeral. So - are the continents the residue of the original crust that wasn’t blasted off? I can imagine an impact that removed pretty much one side of the planet’s crust, and shattered the remains into the continents. Once it all cooled down a new thinner crust formed where no continental crust was left, with the continents now free to be driven about the surface of the planet by the internal movement of fluids. That movement driving the oceanic crust down when it was in the way, and opening up fissures for new oceanic crust to form. IE tectonics.
However I don’t seem to have seen much discussion about this, and when I have quizzed some of the geologist/geophysicist colleagues about it they have not really had much to say. I’m sure there has been some work done.
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [December 1, 2016, 2:21pm UTC](https://boards.straightdope.com/t/earths-moon/773478/29 "2016-12-01T14:21:57Z")
The collision would have happened very early in the history of the solar system, likely inside of the first 100 million years. The Earth would still have been [much hotter](https://www.geol.umd.edu/~jmerck/geol212/lectures/10.html) than it is now. At the stage that Thera would have hit the proto-Earth, the crust would have been much thinner, with [nothing like today’s continental crust](https://en.wikipedia.org/wiki/Continental_crust#Origin). There may even have been only sporadic patches of thin crust floating about on a giant magma ocean. There would have been absolutely nothing about the proto-Earth that would have been remotely recognizable to a time-traveling visitor.
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [December 1, 2016, 2:28pm UTC](https://boards.straightdope.com/t/earths-moon/773478/30 "2016-12-01T14:28:44Z")
Too late to edit, but [the previous page](https://www.geol.umd.edu/%7Ejmerck/geol212/lectures/09.html) in the above linked site is relevant too.
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [January 11, 2017, 11:55pm UTC](https://boards.straightdope.com/t/earths-moon/773478/31 "2017-01-11T23:55:40Z")
[Latest lab work](http://www.theverge.com/2017/1/11/14230448/moon-exact-age-calculated-nasa-apollo-14-samples) suggests that the moon formed within the first 60 million years of the solar system.
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### Author:  [@bob\_2](https://boards.straightdope.com/u/bob_2)
#### Post date: [January 12, 2017, 12:07am UTC](https://boards.straightdope.com/t/earths-moon/773478/32 "2017-01-12T00:07:40Z")
Of course, there is more than one moon: [EarthSky | Minimoons may be usual orbiting Earth](http://earthsky.org/space/earth-usually-has-more-than-one-moon)
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [January 12, 2017, 1:19am UTC](https://boards.straightdope.com/t/earths-moon/773478/33 "2017-01-12T01:19:50Z")
Huh, here I thought that link was going to be about Cruithne, and was all set to point out that it orbits the Sun in a weird way that’s influenced by the Earth. But no, that link really is about rocks that orbit the Earth itself, at least for a while.
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### Author:  [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)
#### Post date: [January 12, 2017, 1:20am UTC](https://boards.straightdope.com/t/earths-moon/773478/34 "2017-01-12T01:20:31Z")
> [@bob\_2](#):
>
> Of course, there is more than one moon: [EarthSky | Minimoons may be usual orbiting Earth](http://earthsky.org/space/earth-usually-has-more-than-one-moon)
If it’s the size of a car, can you really call it a moon?
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### Author:  [@dtilque](https://boards.straightdope.com/u/dtilque)
#### Post date: [January 12, 2017, 1:56am UTC](https://boards.straightdope.com/t/earths-moon/773478/35 "2017-01-12T01:56:05Z")
> [@Chronos](#):
>
> Huh, here I thought that link was going to be about Cruithne,
I provided a link to that way back in post #17.
> [@Nars\_Glinley](#):
>
> If it’s the size of a car, can you really call it a moon?
Maybe if it has a moon roof…
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### Author:  [@cochrane](https://boards.straightdope.com/u/cochrane)
#### Post date: [January 12, 2017, 2:35am UTC](https://boards.straightdope.com/t/earths-moon/773478/36 "2017-01-12T02:35:49Z")
> [@Nars\_Glinley](#):
>
> If it’s the size of a car, can you really call it a moon?
That’s no moon…it’s a Honda!
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### Author:  [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)
#### Post date: [January 12, 2017, 4:49am UTC](https://boards.straightdope.com/t/earths-moon/773478/37 "2017-01-12T04:49:53Z")
We’ve had cars called Mercury & Saturn. Moon’s even smaller.
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### Author:  [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)
#### Post date: [January 12, 2017, 1:05pm UTC](https://boards.straightdope.com/t/earths-moon/773478/38 "2017-01-12T13:05:04Z")
Current headlines about moon-formation hypotheses center around [a paper in _Nature Geoscience_ proposing that the moon formed not from one collision, but rather multiple smaller collisions](http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2866.html).
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [January 12, 2017, 1:23pm UTC](https://boards.straightdope.com/t/earths-moon/773478/39 "2017-01-12T13:23:19Z")
> [@DSYoungEsq](#):
>
> Current headlines about moon-formation hypotheses center around [a paper in _Nature Geoscience_ proposing that the moon formed not from one collision, but rather multiple smaller collisions](http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2866.html).
The one I bumped with (at post 30) isn’t about a computer model, it is about an [isochron dating](http://www.talkorigins.org/faqs/isochron-dating.html) for a real lunar sample.
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### Author:  [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)
#### Post date: [January 12, 2017, 9:34pm UTC](https://boards.straightdope.com/t/earths-moon/773478/40 "2017-01-12T21:34:00Z")
Wiki has an article. Seems a little odd to me that this question is still under debate after so many years, so much research and repeated Apollo landings: [Origin of the Moon - Wikipedia](https://en.wikipedia.org/wiki/Origin_of_the_Moon)
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### Author:  [@Weisshund](https://boards.straightdope.com/u/Weisshund)
#### Post date: [January 14, 2017, 12:25am UTC](https://boards.straightdope.com/t/earths-moon/773478/41 "2017-01-14T00:25:29Z")
> [@Francis\_Vaughan](#):
>
> The thing that puzzles me about this impact is the relationship between continental crust, oceanic crust, tectonics and the residue of the impact.
>
> Continental crust is quite thick, so much so that the continents are basically the same as they have always been. Whereas oceanic crust is very much thinner, and is subject to subduction and recycling. Basically the continents have been around forever, but the oceans are ephemeral. So - are the continents the residue of the original crust that wasn’t blasted off? I can imagine an impact that removed pretty much one side of the planet’s crust, and shattered the remains into the continents. Once it all cooled down a new thinner crust formed where no continental crust was left, with the continents now free to be driven about the surface of the planet by the internal movement of fluids. That movement driving the oceanic crust down when it was in the way, and opening up fissures for new oceanic crust to form. IE tectonics.
>
> However I don’t seem to have seen much discussion about this, and when I have quizzed some of the geologist/geophysicist colleagues about it they have not really had much to say. I’m sure there has been some work done.
Well, i would not say the continents are the same as always
They have moved tens of thousands of miles and are still moving
They have joined and broken apart several times, mountains have risen where there were none, and mountains have returned back into the earth and some edges are continually being pushed under to be recycled, things maybe go at a slower pace than the ocean but they are still going.
[Previous page](https://boards.straightdope.com/t/earths-moon/773478.md?page=1)