# What's the fastest moving body part? **URL:** \ **Category:** Factual Questions\ **Created:** [October 19, 2012, 2:17pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227 "2012-10-19T14:17:19Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Sicks\_Ate](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)\ **Post date:** [October 19, 2012, 6:58pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/21 "2012-10-19T18:58:27Z")
> [@tracer](#): > > If I shot somebody out of a cannon, all of his body parts would be travelling at SEVERAL hundred miles per hour. Strap a bomb to somebody, and they’ll travel even faster. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [October 19, 2012, 7:12pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/22 "2012-10-19T19:12:08Z")
If you drop them out of a balloon 28 miles up, all of the parts can go faster than the speed of sound. It happened to someone recently, I think. Reminds me of the Dave Barry line – “The fastest animal on earth is a cow that has been dropped out of a balloon.” ---
**Author:** ![TruCelt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/trucelt/32/523_2.png) [@TruCelt](https://boards.straightdope.com/u/TruCelt)\ **Post date:** [October 19, 2012, 8:29pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/23 "2012-10-19T20:29:05Z")
Tympanic vibration is the body part being acted upon htough. I though the OP was looking for the body moving of it’s own volition? If so, what about atrial fibrillation? That’s an incredibly fast muscle twitch. . . ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [October 19, 2012, 9:45pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/24 "2012-10-19T21:45:12Z")
I would vote for the vocal cords - since they vibrate at high frequencies ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [October 20, 2012, 1:14am UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/25 "2012-10-20T01:14:25Z")
> [@CalMeacham](#): > > If you drop them out of a balloon 28 miles up, all of the parts can go faster than the speed of sound. > > It happened to someone recently, I think. > > Reminds me of the Dave Barry line – “The fastest animal on earth is a cow that has been dropped out of a balloon.” What about astronauts? The International Space Station moves at an average speed of 4.8 miles per _second_. As for the speed of individual body parts, I think it would be the tip of an arm or leg, since when moving them, the free ends move faster (cover more distance); this also means that a person with really long arms or legs can move them “faster” than a shorter person, assuming that the entire arm/leg completes its swing in the same amount of time (but it is harder to swing a longer arm/leg). ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [October 20, 2012, 1:46am UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/26 "2012-10-20T01:46:56Z")
> [@Michael63129](#): > > … > > As for the speed of individual body parts, I think it would be the tip of an arm or leg, since when moving them, the free ends move faster (cover more distance); this also means that a person with really long arms or legs can move them “faster” than a shorter person, assuming that the entire arm/leg completes its swing in the same amount of time (but it is harder to swing a longer arm/leg). But his fingertips would get there slower from his elbow’s point of view. Relatively. ---
**Author:** ![simster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/simster/32/1047_2.png) [@simster](https://boards.straightdope.com/u/simster)\ **Post date:** [October 20, 2012, 2:24am UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/27 "2012-10-20T02:24:05Z")
Sperm on the way to the egg - or possibly ejaculate during the launch cycle. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [October 20, 2012, 3:08am UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/28 "2012-10-20T03:08:04Z")
> [@simster](#): > > Sperm on the way to the egg No way. Takes several hours for most sperm to make it several inches to the fallopian tubes. > [@](#): > > - or possibly ejaculate during the launch cycle. ~28mph. Impressive, but not mindblowing ---
**Author:** ![Zabali\_Clawbane](https://avatars.discourse-cdn.com/v4/letter/z/ecd19e/32.png) [@Zabali\_Clawbane](https://boards.straightdope.com/u/Zabali_Clawbane)\ **Post date:** [October 20, 2012, 3:24am UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/29 "2012-10-20T03:24:57Z")
What about the eye’s pupils? How do they rate? 😕 The bones in the ear? What about them? ---
**Author:** ![simster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/simster/32/1047_2.png) [@simster](https://boards.straightdope.com/u/simster)\ **Post date:** [October 20, 2012, 4:02am UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/30 "2012-10-20T04:02:45Z")
> [@WhyNot](#): > > No way. Takes several hours for most sperm to make it several inches to the fallopian tubes. > > ~28mph. Impressive, but not mindblowing Sperm on the way to the egg - consider the size of the sperm and the distance traveled/time. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [October 20, 2012, 12:35pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/31 "2012-10-20T12:35:35Z")
> [@Machine\_Elf](#): > > If I’m reading this correctly, you are asserting that a fastball pitch is slower than a karate strike. > > Fastballs (and therefore the fingertips that launch them) are clocked at well over 100 MPH, which beats a 42-MPH karate strike by a wide margin. A thrown object can have a speed higher then the thrower is moving especially when rotational motion is being converted to linear motion. ---
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [October 20, 2012, 1:03pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/32 "2012-10-20T13:03:11Z")
Fastest in relation to what? If you throw a punch, your arm moves quite fast compared to the rest of your body. Your heart is stationary, but it certainly expands and contracts and the surface flesh can be moving at quite a rate. ---
**Author:** ![jmwatts](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jmwatts/32/17348_2.png) [@jmwatts](https://boards.straightdope.com/u/jmwatts)\ **Post date:** [October 20, 2012, 1:19pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/33 "2012-10-20T13:19:48Z")
> [@simster](#): > > Sperm on the way to the egg - consider the size of the sperm and the distance traveled/time. How does the size matter? The distance is short, the time is long.. that means slow. Would apply the same to a pebble or a boulder. ---
**Author:** ![Pitchmeister](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pitchmeister/32/3459_2.png) [@Pitchmeister](https://boards.straightdope.com/u/Pitchmeister)\ **Post date:** [October 20, 2012, 1:27pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/34 "2012-10-20T13:27:39Z")
> [@am77494](#): > > I would vote for the vocal cords - since they vibrate at high frequencies Not a voluntary muscle movement either. The vocal chords vibrate because of the air being pushed through them by the lungs. We mereley control the air flow and the tension of the vocal chords. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [October 20, 2012, 1:45pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/35 "2012-10-20T13:45:47Z")
> [@simster](#): > > Sperm on the way to the egg - consider the size of the sperm and the distance traveled/time. > [@jmwatts](#): > > How does the size matter? I think it’s like Spider-Man supposedly having the “proportionate strength and speed of a spider”\*. Or the claims that if ants were humans sized they could lift a ton or walk 40 mph. Of course, that just means that a tiny creature exists in a very different environment with different biological constraints than a human sized one. \*As an aside, just imagine the embarrassment of being exposed to radioactive sperm and becoming Sperm Man. _“Sperm-Man! Sperm-Man! Does whatever sperm can!”_ ---
**Author:** ![simster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/simster/32/1047_2.png) [@simster](https://boards.straightdope.com/u/simster)\ **Post date:** [October 20, 2012, 1:48pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/36 "2012-10-20T13:48:50Z")
> [@jmwatts](#): > > How does the size matter? The distance is short, the time is long.. that means slow. Would apply the same to a pebble or a boulder. Relative speed - from here - [QUOTE=[Science Articles, Scientific Current Events | Popular Science](http://www.popsci.com/science/article/2012-09/sperm-cant-turn-left-or-dont-want)] Sperm are small, but they’re quick—an individual sperm can wiggle through a space 25 times the length of its body in a single second. (For comparison, a human would have to swim 120 miles per hour to achieve the same relative speed.) [/QUOTE] ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [October 20, 2012, 3:25pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/37 "2012-10-20T15:25:01Z")
Severus Snape when threatened with shampoo. ---
**Author:** ![Gymnopithys](https://avatars.discourse-cdn.com/v4/letter/g/fbc32d/32.png) [@Gymnopithys](https://boards.straightdope.com/u/Gymnopithys)\ **Post date:** [October 20, 2012, 3:26pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/38 "2012-10-20T15:26:01Z")
Your tongue:) ---
**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:** [October 20, 2012, 3:36pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/39 "2012-10-20T15:36:43Z")
That’s nothing: I once moved at 0.9999999999999999999999951c. Well, relative to the Oh-My-God Particle, at least. > [@](#): > > The distance is short, the time is long Not while the evil days come not. ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [October 20, 2012, 6:57pm UTC](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227/40 "2012-10-20T18:57:26Z")
> [@Sicks\_Ate](#): > > According to the gradeschool joke, the fastest thing in the world is your butthole slamming shut after the last turd comes out. > > I do not have a cite. A few years later, many embarrassed Jr High school boys would vote for another part of their anatomy 😃 [Previous page](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227.md?page=1) [Next page](https://boards.straightdope.com/t/whats-the-fastest-moving-body-part/638227.md?page=3)