# Planck length to mass ratio

1. Mar 22, 2009

### delplace

does anyone know something about the ratio of Planck length to Planck mass : signification, use in quantum relationships...

2. Mar 22, 2009

Staff Emeritus
The Planck length is: $$\sqrt{\frac{\hbar G}{c^3}}$$

and the Planck mass is: $$\sqrt{\frac{\hbar c}{G}}$$

The ratio is therefore $G/c^{2}$. Since there is no $\hbar$, it will not appear in "quantum relationships".

Last edited: Mar 22, 2009
3. Mar 22, 2009

### malawi_glenn

Is this post also just for "testing us"? To see if we are worth your time?

4. Mar 22, 2009

### Orion1

Negative, that equation is incorrect.

Planck length:
$$\ell_P = \sqrt\frac{\hbar G}{c^3}$$

Reference:
http://en.wikipedia.org/wiki/Planck_length" [Broken]

Last edited by a moderator: May 4, 2017
5. Mar 22, 2009

Staff Emeritus
Typo fixed. The point that hbar divides out, though, is unaffected.

6. Mar 23, 2009

### Redbelly98

Staff Emeritus
At least nobody is asking for Planck length divided by Planck time ...

Last edited: Mar 23, 2009
7. Mar 24, 2009

### malawi_glenn

Planck colour divided by planck field then?