# Thread: mass of the sun

1. the mass of the sun, according to wikipedia, is 1.9891 x 10^30kg. How was this calculated?  2.

3. how our orbits are.
if we know how long it takes to orbit, then we know either how fast we go, or the distance we go we can calutate the mass of sun by newtons formula v²/r=Gm/r² where m is suns mass,  4. and it gets less by the second cos of the fusion and flares  5. insignifican to the total mass  6. The trouble with that formula is G, the gravitational constant, which is about 6.6742E-11 m^3 s^-2 kg^-1

We can't figure out the suns mass with greater accuracy than we know G, and its value is pretty hard to measure - if we knew the exact mass of the sun we could find G without any trouble and vice versa.

So instead we often use the standard gravitational parameter (written with a greek letter gamma sign) = G*M(sun), since we know the product of G and the mass of the sun with greater accuracy than each values themselves.

So, actually the Q "How do we know the mass of the sun?" isn't all that easy to answer with great accuracy.

best regards,
Michael  7. Originally Posted by Chemboy
the mass of the sun, according to wikipedia, is 1.9891 x 10^30kg. How was this calculated?
It would 300 years of sheer brilliance to arrive at that result. From the time of Keplar to the spectroscopic camera of the Hubble space telescope, various data were analysed and compared to calculate the mass of the sun. You can't put the sun on a beam balance, do you??  8. besides orbiting and usuing kepler stuff...
blue stars are REALLY BIG
light blue stars lighter
white is smaller than blue
etc.
coz heat is form nuke fusion
and how much nuke fusion depends on mass
so mass indirectly makes the colour different and the temperature too
so we know sun surface temp is 5500 C
colour orange yellow
may not be accurate but it narrows the gap  9. notime, please dont press enter all the time, let the program fix the next row  10. Originally Posted by notime
besides orbiting and usuing kepler stuff...
blue stars are REALLY BIG
light blue stars lighter
white is smaller than blue
etc.
coz heat is form nuke fusion
and how much nuke fusion depends on mass
so mass indirectly makes the colour different and the temperature too
so we know sun surface temp is 5500 C
colour orange yellow
may not be accurate but it narrows the gap
I think you are confused with the Hertsprung-Russell diagram which classifies stars on a graph of luminosity V apparent surface temperature.
THere may be trends in size but nothing hard and fast, For example Aldebaran is a giant red star some 40M miles in Dia - there are also very small red stars (stars just large enough to start fusion).  11. oops  