Our solar system is roughly 2.2 x 1020 m away from the center of the Milky Way galaxy, and the system is moving at roughly 231.4 km/s around the galaxy's center. Since most of the galaxy's mass is near its center (and we are on an outer arm of this spiral galaxy), let's model the galaxy has a spherical mass distribution (like a single, giant star that our system is orbiting around). What is the mass of the galaxy (according to our rough, spherical model)? Obviously, this will be a VERY big answer, and so enter in your answer to the order of 1040 kg. In other words, calculate the answer, and then divide by 1040 and then enter in the result. BTW - by assuming that all mass in the galaxy is made up of stars that are about the same mass as our sun, it isn't too hard to then estimate how many stars are in the galaxy!). As an another aside, some measurements and observations that we have taken in Astronomy suggests that in reality, stars only make up a fraction of the total mass
Our solar system is roughly 2.2 x 1020 m away from the center of the Milky Way galaxy, and the system is moving at roughly 231.4 km/s around the galaxy's center. Since most of the galaxy's mass is near its center (and we are on an outer arm of this spiral galaxy), let's model the galaxy has a spherical mass distribution (like a single, giant star that our system is orbiting around).
What is the mass of the galaxy (according to our rough, spherical model)? Obviously, this will be a VERY big answer, and so enter in your answer to the order of 1040 kg. In other words, calculate the answer, and then divide by 1040 and then enter in the result.
BTW - by assuming that all mass in the galaxy is made up of stars that are about the same mass as our sun, it isn't too hard to then estimate how many stars are in the galaxy!). As an another aside, some measurements and observations that we have taken in Astronomy suggests that in reality, stars only make up a fraction of the total mass
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