Estimating Mass of the Milky Way Galaxy

In summary, the sun takes 200 million years to make one rotation around the center of the Milky Way galaxy, which is about 30,000 light years away. With the assumption that the mass distribution of the galaxy is mostly concentrated in a central uniform sphere, we can estimate the mass of our galaxy using the equation G Msun Mgalaxy / r^2 = Mgalaxy v^2/ r. By converting the time into seconds and using the correct values for the mass of the sun and the distance and velocity of the rotation, we can accurately calculate the mass of our galaxy.
  • #1
myoplex11
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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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  • #2
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
 
  • #3
i am not sure what equation to use
 

1. How do scientists estimate the mass of the Milky Way Galaxy?

Scientists use various methods to estimate the mass of the Milky Way Galaxy. One commonly used method is to measure the rotational velocities of stars and gas clouds in the galaxy and calculate the mass based on the amount of gravity needed to keep them in orbit. Another method is to measure the distribution of dark matter, which makes up a significant portion of the galaxy's mass.

2. What is the estimated mass of the Milky Way Galaxy?

The estimated mass of the Milky Way Galaxy is around 1-1.5 trillion times the mass of our Sun. This includes the mass of all the stars, gas, dust, and dark matter within the galaxy.

3. How accurate are these estimates of the Milky Way's mass?

The estimates of the Milky Way's mass are constantly being refined and improved as new data and techniques become available. While some uncertainty remains, current estimates are believed to be accurate within a few percent.

4. What implications does the mass of the Milky Way have on our understanding of the universe?

Understanding the mass of the Milky Way is crucial in our understanding of the larger universe. It can help us determine the overall distribution and amount of dark matter in the universe and how it affects the formation and evolution of galaxies. It also helps us understand our place in the universe and how the Milky Way compares to other galaxies.

5. How does the mass of the Milky Way compare to other galaxies?

The Milky Way is considered a medium sized galaxy, with a mass similar to that of the Andromeda Galaxy. However, it is significantly smaller than some of the largest galaxies known, which can have masses up to 100 times that of the Milky Way.

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