Estimating Mass of the Milky Way Galaxy

AI Thread Summary
To estimate the mass of the Milky Way Galaxy, the sun's rotation around the galaxy's center is considered, with a distance of about 30,000 light years and a rotation period of 200 million years. The gravitational force equation is applied, but there are errors in the initial setup regarding the mass terms used. The correct approach involves using the mass of the galaxy instead of the sun in the centrifugal force equation. Additionally, it is essential to convert the rotation period from years to seconds for accurate calculations. Properly applying these principles will yield an estimate of the galaxy's mass.
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Homework Statement


The sun rotates around the center of the milky way galaxy at a distance of about 30,000 light years (1ly= 9.5*10^15m). if it takes about 200 million years to make one rotation, estimate the mass of our galaxy. Assume that the mass distribution of galaxy is concentrated mostly in a central uniform sphere.


Homework Equations



G Msun Mgalamy / r^2 = Mgalaxy v^2/ r


The Attempt at a Solution


r= (30000 * (9.5 * 10^5) ) m
v= 2 * pi * r / 200 million years
i know i have to convert the years into seconds is my setup right?
 
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You have the equations slighty wrong. Your's would cancel the mass of the galaxy leaving only the mass of the sun.

And yes - you should work in m/kg/s
 
i am not sure what equation to use
 

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