# Mass of the sun

1. Sep 14, 2008

### fk378

1. The problem statement, all variables and given/known data
Find some combination of G, the speed of light c, and some arbitrary mass M, that has units of length. Then evaluate your expression for the mass of the Sun (that is, find the characteristic length associated with that mass). Give your answer in units of km.

3. The attempt at a solution
G has units (m^3)/[(kg)(s^2)]
c= m/s
M= kg

(G)(M)(1/c)= (m^2)/(s)

To get rid of the m^2, I can take a square root, but how can I get rid of the time in seconds in the denominator?

2. Sep 14, 2008

### dlgoff

Would GM/c^2 give the right units?

3. Sep 14, 2008

### fk378

Oh, yes! Thank you...But I don't know what the physical meaning of this length is when using the sun's mass in the equation. Does it have something to do with the gravitational effect the sun has?....and something with the square of the reciprocal of the speed of light...

What about ....this length denoted here is the length of the field of the gravitational constant relative to the sun?

4. Sep 14, 2008

### Kurdt

Staff Emeritus
Its more to do with escape velocities.