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How do astronomers measure the distance to stars? Is it accurate?

In order to figure out how far away a star is, astronomers use a method called parallax. Because of the Earth's revolution about the sun, near stars seem to shift move against the farther stars. This is called parallax shift. By observing the shift, astronomers are able to calculate how far away the star is.

The smaller the parallax shift, the farther away from earth the star is. This method only works for close stars. When the stars are very far away, the parallax shift is too small to measure.

To measure the distance to stars very far away, astronomers compare the true brightness of the star with how bright it looks to us. This method was discovered by American astronomer Henrietta Leavitt in 1912 and used in the early part of the century to find distances to many globular clusters.


Submitted by Viabhav (India)
Submitted by Nasser (Oregon, USA)
Submitted by Larry (Philippines)
(Febuary 10, 1998)



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