# where exactly does the sky start

**URL:** <https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [January 21, 2000, 9:54am UTC](https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462 "2000-01-21T09:54:00Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![mclar32007](https://avatars.discourse-cdn.com/v4/letter/m/7bcc69/32.png) [@mclar32007](https://boards.straightdope.com/u/mclar32007)\
**Post date:** [January 21, 2000, 9:54am UTC](https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462/1 "2000-01-21T09:54:00Z")

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Hey guy’s i’m new at this but i was reading some straight dope when i thought of this question maybe you guy’s can give me your thoughts on where exactly does the sky start thanks :-Þ  
Matt

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**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\
**Post date:** [January 21, 2000, 2:00pm UTC](https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462/2 "2000-01-21T14:00:00Z")

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## What do you mean? How high up in altitude, or how high in elevation above the horizon?

_It is too clear, and so it is hard to see._

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [January 21, 2000, 3:49pm UTC](https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462/3 "2000-01-21T15:49:00Z")

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If you are referring to the “atmosphere” as “sky”, it’s typically accepted to start at sea level.

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**Author:** ![Hyxtryx](https://avatars.discourse-cdn.com/v4/letter/h/7feea3/32.png) [@Hyxtryx](https://boards.straightdope.com/u/Hyxtryx)\
**Post date:** [January 21, 2000, 5:36pm UTC](https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462/4 "2000-01-21T17:36:00Z")

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Are you sure you’re only _reading_ Straight Dope… :’)

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**Author:** ![Rocket](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@Rocket](https://boards.straightdope.com/u/Rocket)\
**Post date:** [January 22, 2000, 6:03am UTC](https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462/5 "2000-01-22T06:03:00Z")

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According to Websters; Sky means upper atmosphere. I believe the boundary between the troposphere and stratosphere is about 7-10 miles up. That would be my vote for where the sky starts.

By the way, does the atmosphere doesn’t start at sea-level at elevations above sea-level.

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**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\
**Post date:** [January 22, 2000, 6:47am UTC](https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462/6 "2000-01-22T06:47:00Z")

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The sky starts about one micron past your corneas.

What I mean by this is that the blue color of the sky is the cummulative effect of all the atmosphere molecules scattering sunlight. That includes the ones near you as well as those higher up.

* * *

–  
Dan Tilque

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**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\
**Post date:** [January 21, 2000, 7:13pm UTC](https://boards.straightdope.com/t/where-exactly-does-the-sky-start/462/7 "2000-01-21T19:13:00Z")

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This should be posted in General Questions.