# What causes thunder?

**URL:** <https://boards.straightdope.com/t/what-causes-thunder/255145>\
**Category:** Factual Questions\
**Created:** [July 14, 2004, 9:26pm UTC](https://boards.straightdope.com/t/what-causes-thunder/255145 "2004-07-14T21:26:24Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Kinthalis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kinthalis/32/16084_2.png) [@Kinthalis](https://boards.straightdope.com/u/Kinthalis)\
**Post date:** [July 14, 2004, 9:26pm UTC](https://boards.straightdope.com/t/what-causes-thunder/255145/1 "2004-07-14T21:26:24Z")

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Well, I know that lightning does. But how exactly? Right now it’s majorly storming out there and the peals of thunder are defeaning. So how does lightning cause the booming sound?

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**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\
**Post date:** [July 14, 2004, 9:43pm UTC](https://boards.straightdope.com/t/what-causes-thunder/255145/2 "2004-07-14T21:43:04Z")

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Because lightning is stupid hot!! It superheats the surrounding air causing all the air molecules to accelerate past the speed of sound - causing a sonic boom.

Don’t worry. A smart person will be by shortly to give you a _really_ good answer.

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**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\
**Post date:** [July 14, 2004, 9:50pm UTC](https://boards.straightdope.com/t/what-causes-thunder/255145/3 "2004-07-14T21:50:20Z")

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That’s basically it. Air expansion along the path of a lightning bolt. Online dictionaries are your friend.

And you can win $78,000 in a bet, if you’re lucky, but that was a different thread.

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**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [July 14, 2004, 10:03pm UTC](https://boards.straightdope.com/t/what-causes-thunder/255145/4 "2004-07-14T22:03:51Z")

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Oh yeah, that’s one theory, but it’s just a theory; there’s no credible evidence to _prove_ that it isn’t actually the hammer of Thor.

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**Author:** ![Kat](https://avatars.discourse-cdn.com/v4/letter/k/b19c9b/32.png) [@Kat](https://boards.straightdope.com/u/Kat)\
**Post date:** [July 15, 2004, 12:28am UTC](https://boards.straightdope.com/t/what-causes-thunder/255145/5 "2004-07-15T00:28:07Z")

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My mother always told me it was angels bowling.

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**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\
**Post date:** [July 15, 2004, 12:30am UTC](https://boards.straightdope.com/t/what-causes-thunder/255145/6 "2004-07-15T00:30:10Z")

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Or Grandma moving furniture around up there.