<p>Useful formulations which have taken some time to dig out:</p>

<p>$G\sim{4.3\times{10^{-6}}}\,\mathrm{kpc}\,\mathrm{M}_{\odot}^{-1}\,\mathrm{km}^{2}\,\mathrm{s}^{-2}$</p>

<p>or </p>

<p>$G\sim{4.3\times{10^{-3}}}\,\mathrm{pc}\,\mathrm{M}_{\odot}^{-1}\,\mathrm{km}^{2}\,\mathrm{s}^{-2}$</p>

CC BY-SA 3.0
2015-11-01T18:54:16.050Z
Typo corrected, should have read pc not kpc. Thank you for the spot.
MichaelJRoberts
CC BY-SA 3.0
2015-11-01T10:30:17.327Z
2015-11-01T18:53:58.033Z
2015-11-01T18:53:58.033Z
MichaelJRoberts
<p>This question relates formalising the gravitational constant, $G$, (which in S.I. units is usually quoted as $\sim6.67\times10^{-11}\,\mathrm{m}^{3}\,\mathrm{kg}^{-1}\,\mathrm{s}^{-2}$) in units which are more appropriate to astrophysics, such as in the field of galaxy dynamics. </p>

<p>What would $G$ be in more appropriate units to astrophysics? </p>

<units>
Astrophysical "unitised" version of the Gravitational constant
MichaelJRoberts
# Astrophysical "unitised" version of the Gravitational constant

(Asked by: username_0 on 2015-11-01)

This question relates formalising the gravitational constant, $G$, (which in S.I. units is usually quoted as $\sim6.67\times10^{-11}\,\mathrm{m}^{3}\,\mathrm{kg}^{-1}\,\mathrm{s}^{-2}$) in units which are more appropriate to astrophysics, such as in the field of galaxy dynamics.

What would $G$ be in more appropriate units to astrophysics?

**Tags:** units

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## 1 answers

### Answer by username_0 on 2015-11-01. Score: 3 | Accepted answer

Useful formulations which have taken some time to dig out:

$G\sim{4.3\times{10^{-6}}}\,\mathrm{kpc}\,\mathrm{M}\_{\odot}^{-1}\,\mathrm{km}^{2}\,\mathrm{s}^{-2}$

or

$G\sim{4.3\times{10^{-3}}}\,\mathrm{pc}\,\mathrm{M}\_{\odot}^{-1}\,\mathrm{km}^{2}\,\mathrm{s}^{-2}$

> **Comments:**
> **username_0**: Typo corrected, should have read pc not kpc. Thank you for the spot.  

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