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Our perspective of the Galaxy is highly biased by the fact that we
are INSIDE IT..
Peering out to the heavens, what do we see?? If we look in all directions, we see a flattened disk. We appear to be at the center, or maybe just slightly off center.. The first model of our galaxy made by William Herschel in the 18th century looked like the one shown below (the Sun's position is denoted by the yellow star). Herschel did not know |
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About the same time, American Astronomer Shapley, used distance estimates
to Globular Clusters to get a different scale and structure to our Galaxy,
shown to the right--->
He argued that these massive clusters must be orbiting the center of our Galaxy, which was NOT at the position of the Sun (which was correct!). He unfortunately overestimated the total SCALE of the galaxy.
Why did he get the scale wrong?? |
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