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Q & A: Why are stars dots in the sky?

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Most recent answer: 10/30/2016
Q:
Why are stars dots in the sky?
- Ancient (age 20)
athens, greece
A:

They appear to be dots because they are so far away.    If you look with your naked eye all of the stars appear as dots. The smallest angular size a lens can resolve is proportional to the wavelength of the light divided by the diameter of the lens. The eye has a diameter of a few millimeters.   However the Hubble Space Telescope has a much larger diameter  (2.4 meters) and its angular resolution is good enough to measure the diameter of a half-dozen of the closest stars.

LeeH


(published on 10/30/2016)

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