# Discovery...sound barrier question

**URL:** <https://boards.straightdope.com/t/discovery-sound-barrier-question/38178>\
**Category:** Factual Questions\
**Created:** [October 24, 2000, 9:55pm UTC](https://boards.straightdope.com/t/discovery-sound-barrier-question/38178 "2000-10-24T21:55:09Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![OliverTwistofLime](https://avatars.discourse-cdn.com/v4/letter/o/b487fb/32.png) [@OliverTwistofLime](https://boards.straightdope.com/u/OliverTwistofLime)\
**Post date:** [October 24, 2000, 9:55pm UTC](https://boards.straightdope.com/t/discovery-sound-barrier-question/38178/1 "2000-10-24T21:55:09Z")

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What causes the bam-bam (like someone slamming the door shut twice quickly whe the shuttle breaks the sound barrier? I have heard a few of these identical sounds when the space shuttle terminates its landing at Edwards Air Force Base. And exactly at 1:57pm today pacific coast time there it was.

I did try to search under sonic boom and the sound barrier but everything I got referred to musical groups. So in short, why 2 bams, not one or 3?

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**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\
**Post date:** [October 24, 2000, 10:47pm UTC](https://boards.straightdope.com/t/discovery-sound-barrier-question/38178/2 "2000-10-24T22:47:43Z")

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One sonic boom is caused by the nose, the second by the tail. For a very good explanation of sonic booms, see [http://web.galcit.caltech.edu/SonicBoom/boomprimer.html](http://web.galcit.caltech.edu/SonicBoom/boomprimer.html)

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**Author:** ![OliverTwistofLime](https://avatars.discourse-cdn.com/v4/letter/o/b487fb/32.png) [@OliverTwistofLime](https://boards.straightdope.com/u/OliverTwistofLime)\
**Post date:** [October 24, 2000, 11:29pm UTC](https://boards.straightdope.com/t/discovery-sound-barrier-question/38178/3 "2000-10-24T23:29:58Z")

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Bibliophage: the link you gave me explains it perfectly. Thanks for directing me there!

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**Author:** ![John\_Kentzel-Griffin](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@John\_Kentzel-Griffin](https://boards.straightdope.com/u/John_Kentzel-Griffin)\
**Post date:** [October 25, 2000, 7:26am UTC](https://boards.straightdope.com/t/discovery-sound-barrier-question/38178/4 "2000-10-25T07:26:46Z")

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There was a thread here [Photgraph(sic) sound barrier?](http://boards.straightdope.com/sdmb/showthread.php?threadid=14669). In it, **the\_nudge** aka **crnugent** posted [this link.](http://artbell.com/graphics15.html) The first link on that page is to an mpeg showing the shock wave. Check it out!