# Talk:Geometrized unit system

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## Title

Should this be moved to geometrized unit (singular)? Sometimes the plural is appropriate in an article title; is this such a case? Michael Hardy 15:46, 18 Dec 2003 (UTC)

I moved it to geometrized unit system, for in this case the plural was used to identify a category. Thanks for the comment.

## 8πG=1

Isn't sometimes 8πG set to 1? --Pjacobi 11:05, July 31, 2005 (UTC)

There actually are several different systems involved here. Your "sometimes" and the "sometimes" starting the second paragaph of the article are clues to that fact. Gene Nygaard 11:16, 31 July 2005 (UTC)

Yes, 8πG is another common convention, as is 16πG=1. This is problematic. My impression is that the most common modern convention is 8πG=1, but I could be mistaken. –Joke137 18:10, 2 October 2005 (UTC)

But what about Wald, General relativity, Appendix F, which uses c = G =1? This is probably the most widely used graduate textbook on general relativity in the English-speaking world. Can anyone cite a major textbook which used either of the other two conventions mentioned by Joke137? ---CH (talk) 01:33, 3 October 2005 (UTC)

## Students beware

Just wanted to provide notice that I am only responsible (in part) for the last version I edited; see User:Hillman/Archive. I emphatically do not vouch for anything you might see in more recent versions, although I hope for the best.

Good luck in your search for information, regardless!---CH 23:52, 30 June 2006 (UTC)

## MKS charge units

I believe there should be a entry for converting SI charge units in the official conversion table.

Using google calculator, I get for the conversion constant:

${\displaystyle {\sqrt {G/4\pi \epsilon _{0}c^{4}}}}$ = sqrt(G / (4 * Pi * electric constant * c^4)) = 8.61667791 × 10-18 m / coulomb

question: what source should be used for constant values?

Pervect 23:09, 22 July 2006 (UTC)

## Edits

I've made the edits indicated above, having gotten no comments. The conversion table from Wald is for cgs units, unfortunately. This would only matter for charge and related electrical units. I've marked up the table to indicate it's a cgs table as the simplest course of action to fix the issue.

consistency checks:

1 statcolumb * sqrt(G)/c^2 -> 2.87 * 10^-25 cm = 2.87* 10^-27 m
1 coulomb -> 8.62 * 10^-18 m (from MKS table)
1 statcolumb / 1 coulomb = 3.33*10^-10

consistent with http://en.wikipedia.org/wiki/Statcoulomb This is incosistent with the wiki cgs page, however!

more consistency checks:

charge of electron = 1.381*10^-34 cm (MTW back cover)
charge of electron = 1.60*10^-19 coulomb * 8.62*10^-18 m/coulomb = 1.38*10^-36 m = 1.38*10^-34 cm

Pervect 22:41, 29 July 2006 (UTC)

## More edits

I went through and added the SI units and conversion factors to the table (a major edit at least in terms of work).

I cross-checked the conversion formulas for SI units with google calculator. Examples (cut and paste the following formula into google calc). epsilon_0 is "electric constant" in Google.

(ampere)*(sqrt(G/(4*pi*electric constant)))/c^3=
(tesla)*(sqrt(G*(4*pi*electric constant))/c)=
(volt)*(sqrt(G*(4*pi*electric constant))/c^2)=

## Conversion factors between meter, kilogram, second, coulomb and kelvin

Here you have all needed conversion factors that covers all SI base units, and if not possible, their unique elements:

into m

• G/c^2 [m/kg]
• c [m/s]
• ((G/(4*pi*(electric constant)))^0.5)/c^2 [m/C]
• (G*k)/c^4 [m/K]

into kg

• c^2/G [kg/m]
• c^3/G [kg/s]
• 1/(G*4*pi*(electric constant))^0.5 [kg/C]
• k/c^2 [kg/K]

into s

• 1/c [s/m]
• G/c^3 [s/kg]
• ((G/(4*pi*(electric constant)))^0.5)/c^3 [s/C]
• (G*k)/c^5 [s/K]

into C

• c^2/((G/(4*pi*(electric constant)))^0.5) [C/m]
• (G*4*pi*(electric constant))^0.5 [C/kg]
• c^3/((G/(4*pi*(electric constant)))^0.5) [C/s]
• (k*(G*4*pi*(electric constant))^0.5)/c^2 [C/K]

into K

• c^4/(G*k) [K/m]
• c^2/k [K/kg]
• c^5/(G*k) [K/s]
• c^2/(k*(G*4*pi*(electric constant))^0.5) [K/C]

All these units represents nothing else than distance along dimension, that makes SI redundant in comparison to geometrized units. I added all these abovementioned factors after proper formatting to article. They can be verified in Google calculator.

## Introduction

Hello Pervect

It seems that the sentence is incomplete:

In situations involving electrical units, we add the constraint that the quantity 4πε0, where ε0 is vacuum permittivity. 83.30.48.117 (talk) 18:00, 28 October 2009 (UTC)

as it is now, the two entries "elecitric potential" and "potential" (the very last) are identical. would it not make much more sense to interpret the second potential as gravitational potential? then its SI dimension would be [L2 T-2] (the same as energy/mass), and the multiplication factor would just be c-2. --Diogenes2000 (talk) 02:50, 30 December 2012 (UTC)

## Potential

as it is now, the two entries "elecitric potential" and "potential" (the very last) are identical. would it not make much more sense to interpret the second potential as gravitational potential? then its SI dimension would be [L2 T-2] (the same as energy/mass), and the multiplication factor would just be c-2. --Diogenes2000 (talk) 02:51, 30 December 2012 (UTC)