<p>If we accept <a href="http://en.wikipedia.org/wiki/Giant_impact_hypothesis" rel="noreferrer">the Giant impact hypothesis</a>, which says that the Moon was once a part of the Earth pushed away by a big impact, the answer is obviously 0.</p>

CC BY-SA 3.0
2015-07-10T22:31:05.137Z
The link is no longer accurate, so I'll repost.   http://curious.astro.cornell.edu/our-solar-system/37-our-solar-system/the-moon/the-moon-and-the-earth/31-how-close-was-the-moon-to-the-earth-when-it-formed-intermediate   A precise answer isn't possible due to varying factors, but about 3-5 earth radii, in other words, pretty darn close.
userLTK
CC BY-SA 3.0
2014-01-24T22:00:51.467Z
Arguably it wasn't yet the Moon at that point, just a cloud of molten or vaporized rock and debris. At some vaguely-defined point, it became a coherent object. I wonder how far from Earth it was at that point.
Keith Thompson
CC BY-SA 3.0
2014-01-27T09:15:01.223Z
@KeithThompson It was not, for sure, inside the Roche Limit.
Envite
CC BY-SA 3.0
2014-01-27T16:53:36.347Z
Excellent point. It's likely that much of the debris from the collision was quickly thrown outside the Roche Limit (and that much of the debris that wasn't thrown outside that limit fell back onto the Earth). So the question is, what was the distance of the bulk of the debris at the time when it first coalesced into a single coherent body? A real answer to that question would require running a detailed computer model of the event (something that's probably already been done).
Keith Thompson
CC BY-SA 3.0
2014-01-27T17:56:00.613Z
I think a more interesting interpretation of the question might be, "when the moon first accreted into a discrete body or was captured into orbit, how close was it?"
Larry Gritz
CC BY-SA 3.0
2014-02-13T00:20:57.960Z
http://curious.astro.cornell.edu/question.php?number=699
Ňɏssa Pøngjǣrdenlarp
CC BY-SA 3.0
2014-01-21T21:36:55.240Z
2014-01-22T14:15:30.023Z
2014-01-22T14:15:30.023Z
Envite
<p>For every year, the moon is orbiting further away from earth.</p>

<p>What distance has the moon been from earth at the closest?</p>

CC BY-SA 3.0
2014-01-21T22:53:34.647Z
This may prove difficult to answer since some theories about the formation of the moon state that it was a part of earth that separated when earth got hit by a very large meteorite. If this were true, then the moon was 'inside' the earth so to say
Eduardo Serra
<the-moon><earth><near-earth-object>
What distance has the moon been from earth at the closest?
Fellow Stranger
# What distance has the moon been from earth at the closest?

(Asked by: username_0 on 2014-01-21)

For every year, the moon is orbiting further away from earth.

What distance has the moon been from earth at the closest?

**Tags:** the-moon, earth, near-earth-object
> **Comments:**
> **username_1**: This may prove difficult to answer since some theories about the formation of the moon state that it was a part of earth that separated when earth got hit by a very large meteorite. If this were true, then the moon was 'inside' the earth so to say  

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## 1 answers

### Answer by username_2 on 2014-01-21. Score: 6 | Accepted answer

If we accept [the Giant impact hypothesis](http://en.wikipedia.org/wiki/Giant_impact_hypothesis), which says that the Moon was once a part of the Earth pushed away by a big impact, the answer is obviously 0.

> **Comments:**
> **username_4**: Arguably it wasn't yet the Moon at that point, just a cloud of molten or vaporized rock and debris. At some vaguely-defined point, it became a coherent object. I wonder how far from Earth it was at that point.  
> **username_2**: @KeithThompson It was not, for sure, inside the Roche Limit.  
> **username_4**: Excellent point. It's likely that much of the debris from the collision was quickly thrown outside the Roche Limit (and that much of the debris that wasn't thrown outside that limit fell back onto the Earth). So the question is, what was the distance of the bulk of the debris at the time when it first coalesced into a single coherent body? A real answer to that question would require running a detailed computer model of the event (something that's probably already been done).  
> **username_5**: I think a more interesting interpretation of the question might be, "when the moon first accreted into a discrete body or was captured into orbit, how close was it?"  
> **username_6**: http://curious.astro.cornell.edu/question.php?number=699  
> **username_3**: The link is no longer accurate, so I'll repost.   http://curious.astro.cornell.edu/our-solar-system/37-our-solar-system/the-moon/the-moon-and-the-earth/31-how-close-was-the-moon-to-the-earth-when-it-formed-intermediate   A precise answer isn't possible due to varying factors, but about 3-5 earth radii, in other words, pretty darn close.  

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