# Gravitational constant?

**URL:** <https://boards.straightdope.com/t/gravitational-constant/59904>\
**Category:** Factual Questions\
**Created:** [March 29, 2001, 12:25am UTC](https://boards.straightdope.com/t/gravitational-constant/59904 "2001-03-29T00:25:10Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\
**Post date:** [March 29, 2001, 12:25am UTC](https://boards.straightdope.com/t/gravitational-constant/59904/1 "2001-03-29T00:25:10Z")

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How does Newton’s constant of gravitation figure into  
E=mc^2?

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**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\
**Post date:** [March 29, 2001, 3:01am UTC](https://boards.straightdope.com/t/gravitational-constant/59904/2 "2001-03-29T03:01:52Z")

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You need an understanding of Newton’s law of gravity, not just the constant. The force is proprtional to the product of two attractive masses divided by the square of the distance between centers.

Relativity is far more than E=MC[SUP]2[/SUP] It exlains why newton’s laws don’t quite fit at very hight speeds and for very large masses. It is a different model of gravity. Instead of being an attractive force between any two masses it says that every mass warps space.

This is pretty advanced stuff. If you take a year long college physics course you won’t get to relativity until the end of the course.

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**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\
**Post date:** [March 29, 2001, 3:39am UTC](https://boards.straightdope.com/t/gravitational-constant/59904/3 "2001-03-29T03:39:47Z")

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The  
[Newtonian constant of gravitation](http://physics.nist.gov/cgi-bin/cuu/Value?bg%7Csearch_for=gravitational+constant) is:

**6.673(10) x 10[sup]-11[/sup] m[sup]3[/sup] kg[sup]-1[/sup] s[sup]-2[/sup]**

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**Author:** ![Opus1](https://avatars.discourse-cdn.com/v4/letter/o/858c86/32.png) [@Opus1](https://boards.straightdope.com/u/Opus1)\
**Post date:** [March 29, 2001, 6:46am UTC](https://boards.straightdope.com/t/gravitational-constant/59904/4 "2001-03-29T06:46:49Z")

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> [@](#):
>
> How does Newton’s constant of gravitation figure into  
> E=mc^2?

It doesn’t. In fact, one of the great difficulties that scientists have had in determining the precise value of “Big G” is that it can only be determined directly, and experimentally. It is not intertwined with any other physical constant. Planck’s constant, the speed of light, the charge of the electron, etc. are all linked together several times over. But G sits aloof, removed from virtually all such relationships.