Finding the mass of our Galaxy and the amount of stars in our Galaxy

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The discussion revolves around estimating the mass of the Milky Way Galaxy and the number of stars it contains based on the sun's rotation and mass distribution. The user calculated the Galaxy's mass to be approximately 3.44425x10^41 kg and estimated around 1.72213x10^11 stars, expressing uncertainty about the accuracy of these figures. Other participants in the thread affirm that the calculations appear reasonable, questioning why the user doubts their results. The conversation emphasizes the methodology used in the calculations, focusing on the assumptions made regarding mass distribution and the sun's orbital parameters. Overall, the thread highlights the complexities of astronomical calculations and the importance of peer verification in homework problems.
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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 from the center (1 light year=9.5x10^15 meters). If it takes about 200 million years to make one rotation, estimate the mass of our Galaxy. Assume that the mass distribution of our Galaxy is concentrated mostly in a central uniform sphere. If all the stars had about the mass of our sun (2x10^30 kg), how many stars would there be in our Galaxy?


Homework Equations





The Attempt at a Solution



For the mass of the Galaxy I got an answer of 3.44425x10^41 kg and I got 1.72213x10^11 stars. I'm pretty sure this isn't right. HELP!?
 
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That looks about right to me. Why do you think it's wrong?
 

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