Measuring the Distances to Stars and Galaxies

AI Thread Summary
Parallax is a method used to measure distances to stars within 400 light years of Earth by observing the displacement of foreground and background objects. For more distant stars and galaxies, astronomers typically calculate distances by comparing their brightness to that of nearby objects of the same type. The discussion highlights confusion around the concept of parallax and its measurement methods. There is also a reference to a link providing additional information on star distance measurement. Overall, the conversation emphasizes the importance of understanding both parallax and comparative brightness in astronomical distance calculations.
McHeathen
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As I understand it we can use the principle of parallax to measure distances to objects within 400 light years from Earth. So how are the further stars and galaxies calculated?
 
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Usually by comparing brightness with nearby objects of the same type.
 
This is so bad I don't know quite where to start. Parallax is the displacement between foreground and background objects. You measure it with yardsticks.
 
Chronos said:
This is so bad I don't know quite where to start. Parallax is the displacement between foreground and background objects. You measure it with yardsticks.

:rolleyes: ..by yardsticks, you mean, comparison to solar system scales??

Are you the Straight Dope Science Advisory Board's Chronos?
 

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