# Twinkling stars... twinkling planets??

**URL:** <https://boards.straightdope.com/t/twinkling-stars-twinkling-planets/200323>\
**Category:** Factual Questions\
**Created:** [September 8, 2003, 3:51pm UTC](https://boards.straightdope.com/t/twinkling-stars-twinkling-planets/200323 "2003-09-08T15:51:52Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Lenny\_Carl](https://avatars.discourse-cdn.com/v4/letter/l/9dc877/32.png) [@Lenny\_Carl](https://boards.straightdope.com/u/Lenny_Carl)\
**Post date:** [September 8, 2003, 3:51pm UTC](https://boards.straightdope.com/t/twinkling-stars-twinkling-planets/200323/1 "2003-09-08T15:51:52Z")

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I was taught that stars “twinkle” because they are producing their own light, while planets do not “twinkle” because they are simply reflecting our suns light.

What is the SD on this?

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**Author:** ![micco](https://avatars.discourse-cdn.com/v4/letter/m/5f8ce5/32.png) [@micco](https://boards.straightdope.com/u/micco)\
**Post date:** [September 8, 2003, 4:09pm UTC](https://boards.straightdope.com/t/twinkling-stars-twinkling-planets/200323/2 "2003-09-08T16:09:50Z")

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The twinkle is a result of atmospheric interference. Anything viewed through the atmosphere twinkles.

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [September 8, 2003, 4:10pm UTC](https://boards.straightdope.com/t/twinkling-stars-twinkling-planets/200323/3 "2003-09-08T16:10:11Z")

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Stars and planets both twinkle because the earth’s atmosphere is unstable and contains pockets of lower and higher density air which magnify and distort the light of celestial objects. The effect is just less obvious with planets because they are already so bright.

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**Author:** ![MaryEFoo](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@MaryEFoo](https://boards.straightdope.com/u/MaryEFoo)\
**Post date:** [September 8, 2003, 4:20pm UTC](https://boards.straightdope.com/t/twinkling-stars-twinkling-planets/200323/4 "2003-09-08T16:20:17Z")

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I was taught that stars “twinkle” because they are so far, their apparent size as their light enters the atmosphere is the same size as you see it, a pinpoint.

Planets are so much closer that their apparent size is a speck, bigger than a pinpoint. Although they do not shine by their own light, they look roughly as bright as stars since they are larger.

The refraction due to varying densities/temperatures of the atmosphere causes the light from the stars to be rippled back and forth. The incoming light from planets is also refracted, but the light from the left edge is as likely to move toward the center of the speck as away from it, and the same for the right edge, so the brightness of the center of the speck stays steadier.