# How far from the earth do you have to be to start falling toward the moon?

**URL:** <https://boards.straightdope.com/t/how-far-from-the-earth-do-you-have-to-be-to-start-falling-toward-the-moon/496082>\
**Category:** Factual Questions\
**Created:** [May 11, 2009, 8:49pm UTC](https://boards.straightdope.com/t/how-far-from-the-earth-do-you-have-to-be-to-start-falling-toward-the-moon/496082 "2009-05-11T20:49:34Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sweeteviljesus](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@sweeteviljesus](https://boards.straightdope.com/u/sweeteviljesus)\
**Post date:** [May 11, 2009, 8:49pm UTC](https://boards.straightdope.com/t/how-far-from-the-earth-do-you-have-to-be-to-start-falling-toward-the-moon/496082/1 "2009-05-11T20:49:34Z")

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Is there some point in space between the Earth and the Moon where the latter’s gravity becomes predominate and you start falling toward it rather than the Earth? Is there point where the Sun’s gravity is stronger than the two? Let’s assume that a mass at that point has an initial velocity of 0.

Thanks,  
Rob

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**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\
**Post date:** [May 11, 2009, 8:54pm UTC](https://boards.straightdope.com/t/how-far-from-the-earth-do-you-have-to-be-to-start-falling-toward-the-moon/496082/2 "2009-05-11T20:54:27Z")

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Seems easiest to just cite this:

> [@](#):
>
> Easily done using Newton’s Law of gravitation (F = GMm/rr) if you know  
> the mass of the earth (5.974E24 kg), the moon (7.347E22 kg) and the  
> distance between them (3.84E8 m or 238,660 = 2.3866E5 miles). The  
> answer is 3.46E8 m or 214,840 miles, about 90% of the earth-moon  
> distance.
> 
> SOURCE: [http://www.newton.dep.anl.gov/askasci/phy00/phy00570.htm](http://www.newton.dep.anl.gov/askasci/phy00/phy00570.htm)

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**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\
**Post date:** [May 11, 2009, 9:10pm UTC](https://boards.straightdope.com/t/how-far-from-the-earth-do-you-have-to-be-to-start-falling-toward-the-moon/496082/3 "2009-05-11T21:10:51Z")

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[This might also be useful.](http://en.wikipedia.org/wiki/Lagrangian_point)