# Is there an "entering velocity" for the atmosphere at which you won't burn up?

**URL:** <https://boards.straightdope.com/t/is-there-an-entering-velocity-for-the-atmosphere-at-which-you-wont-burn-up/475541>\
**Category:** Factual Questions\
**Created:** [December 3, 2008, 6:36pm UTC](https://boards.straightdope.com/t/is-there-an-entering-velocity-for-the-atmosphere-at-which-you-wont-burn-up/475541 "2008-12-03T18:36:25Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![BrandonR](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@BrandonR](https://boards.straightdope.com/u/BrandonR)\
**Post date:** [December 4, 2008, 5:25pm UTC](https://boards.straightdope.com/t/is-there-an-entering-velocity-for-the-atmosphere-at-which-you-wont-burn-up/475541/21 "2008-12-04T17:25:09Z")

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> [@Santo\_Rugger](#):
>
> One of my most memorable parts of a textbook was from a vector analysis text. It stated an axiom, and said, “the laborious proof is left to the reader (or you can read section 2.13).” There was no section 2.13! :smack: The class sucked, but the book was written in a humorous but professional way. I wish the authors of other tedious texts approached their writing that way.

Amen brother. I’ve had to drudge through so many tedious, technical introductory books on topics that skim over so many basic explanations and concepts that I often ask myself why these people are teachers in the first place. Just because you have a PhD does _not_ mean you can teach well! /rant 🙂

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [December 4, 2008, 6:52pm UTC](https://boards.straightdope.com/t/is-there-an-entering-velocity-for-the-atmosphere-at-which-you-wont-burn-up/475541/22 "2008-12-04T18:52:51Z")

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> [@](#):
>
> You’re right that the heat still needs to be dissipated somehow. However, the OP asserted (and many people believe) that the heating up is due to friction, which is not the case.

Unless by “friction” you mean “any dissipative force”, as many do. In which casethe compressive heating in front of the craft is a kind of friction.

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**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\
**Post date:** [December 4, 2008, 7:04pm UTC](https://boards.straightdope.com/t/is-there-an-entering-velocity-for-the-atmosphere-at-which-you-wont-burn-up/475541/23 "2008-12-04T19:04:35Z")

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> [@Chronos](#):
>
> Unless by “friction” you mean “any dissipative force”, as many do. In which casethe compressive heating in front of the craft is a kind of friction.

Maybe I’m relying on Wiki too much, but they talk extensively about different types of friction, and compressible effects is not one of them. “Friction” is also not anywhere on [the wave drag](http://en.wikipedia.org/wiki/Wave_drag) page. It’s a form of drag, not a form of friction.

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