# What would happen to sound if I traveled at Mach 1?

**URL:** <https://boards.straightdope.com/t/what-would-happen-to-sound-if-i-traveled-at-mach-1/192847>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [August 4, 2003, 7:19am UTC](https://boards.straightdope.com/t/what-would-happen-to-sound-if-i-traveled-at-mach-1/192847 "2003-08-04T07:19:07Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![RefridgeratorRaider](https://avatars.discourse-cdn.com/v4/letter/r/8dc957/32.png) [@RefridgeratorRaider](https://boards.straightdope.com/u/RefridgeratorRaider)\
**Post date:** [August 4, 2003, 7:19am UTC](https://boards.straightdope.com/t/what-would-happen-to-sound-if-i-traveled-at-mach-1/192847/1 "2003-08-04T07:19:07Z")

</div>

Just going through some of the older stuff and came across this one.  
[http://www.straightdope.com/classics/a1\_116.html](http://www.straightdope.com/classics/a1_116.html)

In the reader asks:

> [@](#):
>
> What phenomenon would occur if I shifted into second around North Avenue and my Buick exceeded the speed of light?

and Cecil replies:

> [@](#):
>
> Finally, regarding your last question, don’t you know the velocity of light is the speed limit of the universe? Any attempt to exceed it would defy one of the fundamental principles of creation. Besides, it’s hell on the tires.

Well not entirely true anymore. Recent studies show that it is possible to make light travel faster through cesium gas than pure vacuum. Apperantly when a pulse of light what fired through cesium gas it actually exited the chamber before it had finished entering it (not quite travelling back in time as some theories would suggest).

Source:  
[http://www.cbsnews.com/stories/2000/07/19/tech/main216905.shtml](http://www.cbsnews.com/stories/2000/07/19/tech/main216905.shtml)

---

<div class="post-metadata">

**Author:** ![biqu](https://avatars.discourse-cdn.com/v4/letter/b/7feea3/32.png) [@biqu](https://boards.straightdope.com/u/biqu)\
**Post date:** [August 4, 2003, 9:43am UTC](https://boards.straightdope.com/t/what-would-happen-to-sound-if-i-traveled-at-mach-1/192847/2 "2003-08-04T09:43:34Z")

</div>

Welcome to the SDMB, **RefridgeratorRaider**.

Keep in mind that accurate scientific reporting is rarely to be found in the major news channels. A better synopsis and interpretation of the experimental results can probably be obtained from the [scientists themselves](http://www.nec.co.jp/press/en/0007/images/1901.pdf).

Some relevant quotes:

> [@](#):
>
> Our experiment is not at odds with Einstein’s special relativity. The experiment can be well explained using existing physics theories that are consistent with Relativity. In fact, the experiment was designed based on calculations using existing physics theories.
> 
> However, our experiment does show that the generally held misconception “nothing can move faster than the speed of light” is wrong. The statement only applies to objects with a rest mass. Light can be viewed as waves and has no mass. Therefore, it is not limited by its speed inside a vacuum.
> 
> Information coded using a light pulse cannot be transmitted faster than c using this effect. Hence, it is still true to say that “Information carried by a light pulse cannot be transmitted faster than c.”

Since a Buick has nonzero rest mass, Cecil was correct in telling his readers that it cannot exceed the speed of light.

---

<div class="post-metadata">

**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:** [August 4, 2003, 6:34pm UTC](https://boards.straightdope.com/t/what-would-happen-to-sound-if-i-traveled-at-mach-1/192847/3 "2003-08-04T18:34:47Z")

</div>

An analogy for these types of experiments: Suppose I’m walking through a doorway, travelling at the Speed of Chronos. I walk with my arms out in front of me. Now, unless the doorway is exceptionally thick, my hands are going to leave the doorway before my body enters it. Does this mean that I’m travelling at faster than the Speed of Chronos, or that I’m going back in time? No, of course not.

The situation is analogous with almost all of the claimed “light faster than light” experiments. They’re using a light pulse of some length, and measuring different parts of the pulse. They’re counting the pulse as having gone into the material when the middle of the pulse goes in, but counting it as leaving when the leading edge of the pulse leaves. Put it that way, and you realize just how boring these experiments really are.