# Speed of light/relativity question **URL:** \ **Category:** Factual Questions\ **Created:** [August 20, 2009, 8:32pm UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119 "2009-08-20T20:32:50Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![Daylate](https://avatars.discourse-cdn.com/v4/letter/d/9dc877/32.png) [@Daylate](https://boards.straightdope.com/u/Daylate)\ **Post date:** [August 22, 2009, 10:53pm UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/21 "2009-08-22T22:53:02Z")
If I understand the OP’s question, I think it was settled pretty thoroughly by one of the most famous experiments in physics, namely the Michelson-Morley experiment in 1887. It was one that eventually put Einstein on the track of the Theory of Relativity. Link: [http://scienceworld.wolfram.com/physics/Michelson-MorleyExperiment.html](http://scienceworld.wolfram.com/physics/Michelson-MorleyExperiment.html) ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [August 22, 2009, 11:55pm UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/22 "2009-08-22T23:55:05Z")
> [@Chronos](#): > > In any sort of universe at all, it is still true that light always moves at c relative to me, as measured in my reference frame. Hey! You think just because youre an ex-Mod and SDSAB, you have a privileged reference frame? 😛 ---
**Author:** ![KellyCriterion](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@KellyCriterion](https://boards.straightdope.com/u/KellyCriterion)\ **Post date:** [August 23, 2009, 1:50am UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/23 "2009-08-23T01:50:54Z")
> [@jackdavinci](#): > > I tend to prefer giving the more honest and truthful answer, usually “I don’t know” or “that depends on what you mean” or “I’d rather not have to try and explain that right now”. x2. ---
**Author:** ![The\_Seventh\_Deadly\_Finn](https://avatars.discourse-cdn.com/v4/letter/t/6bbea6/32.png) [@The\_Seventh\_Deadly\_Finn](https://boards.straightdope.com/u/The_Seventh_Deadly_Finn)\ **Post date:** [August 24, 2009, 7:22am UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/24 "2009-08-24T07:22:44Z")
> [@Telcontar](#): > > Why is the speed of light constant in all frames of reference? I understand how much of the rest follows from that premise (aka I can make the math work), but I’ve never gotten the “why” aspect. I don’t know. And neither does anybody else (that we know of). It’s a good question though, and my desire to be around when somebody figures it out is one of the better reasons I can think of to live a long life. ---
**Author:** ![KellyCriterion](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@KellyCriterion](https://boards.straightdope.com/u/KellyCriterion)\ **Post date:** [August 24, 2009, 11:52am UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/25 "2009-08-24T11:52:28Z")
Just trying to deepen my understanding of this counter-intuitive theory. Any responses would be greatly appreciated. Let’s say a square room has lightbulb right in the middle of the roof. If the light is turned on, the light travels out from the bulb and hits all 4 walls at the same time. Now, let’s say this square room is hurtling along at 0.5 times the speed of light. the lightbulb is switched on. The observer in the room would still see the light touch all 4 walls at the same time. If my understanding of this theory is correct, would a “stationery observer” watching this room flying past, see the light from the bulb hit the wall behind it first, and it front of it last? (The “front” wall being the wall in the direction the room is traveling). Is that right? ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [August 24, 2009, 2:42pm UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/26 "2009-08-24T14:42:00Z")
> [@KellyCriterion](#): > > If my understanding of this theory is correct, would a “stationery observer” watching this room flying past, see the light from the bulb hit the wall behind it first, and it front of it last? Yes. You may find the [Barn & Pole Paradox](http://math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html) interesting. ---
**Author:** ![Telcontar](https://avatars.discourse-cdn.com/v4/letter/t/3bc359/32.png) [@Telcontar](https://boards.straightdope.com/u/Telcontar)\ **Post date:** [August 24, 2009, 5:46pm UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/27 "2009-08-24T17:46:49Z")
> [@The\_Hamster\_King](#): > > Yes. > > You may find the [Barn & Pole Paradox](http://math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html) interesting. This is why I think that special relativity and quantum mechanics are evidence for the existence of a God who likes f-ing with us :-P. I’ve spent some time thinking about that paradox and only gotten a headache for my troubles. It really doesn’t make sense to me. ---
**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 24, 2009, 6:06pm UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/28 "2009-08-24T18:06:27Z")
The short answer to the barn and pole paradox is that something’s going to break (most likely either the pole or the back door of the barn). The question is just whether it breaks before or after you get the front door closed, and that depends on the reference frame. But either way, no matter what frame you’re in, something ends up broken. ---
**Author:** ![KellyCriterion](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@KellyCriterion](https://boards.straightdope.com/u/KellyCriterion)\ **Post date:** [August 26, 2009, 12:10am UTC](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119/29 "2009-08-26T00:10:32Z")
Thank you to everyone. [Previous page](https://boards.straightdope.com/t/speed-of-light-relativity-question/507119.md?page=1)