# How to have light move faster than C **URL:** \ **Category:** The BBQ Pit\ **Created:** [February 24, 2014, 9:53pm UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160 "2014-02-24T21:53:29Z")\ **Posts on this page:** 20\ **Page:** 2
**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:** [February 25, 2014, 12:23am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/22 "2014-02-25T00:23:07Z")
> [@mythoughts](#): > > Sceptics are by default defenders of the trailing edge and will always oppose the leading edge of science and technology. > Be one if you want, but they always look very stupid and small minded with enough hind sight. These statements (and others in this thread) win you big points values on the [Crackpot Index](http://math.ucr.edu/home/baez/crackpot.html). Just sayin’ ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [February 25, 2014, 12:25am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/23 "2014-02-25T00:25:01Z")
Plus your thought experiment examples tended to document their theories with copious amounts of math. ---
**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:** [February 25, 2014, 12:27am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/24 "2014-02-25T00:27:50Z")
> [@Der\_Trihs](#): > > Actually, no. _c_ is a physical constant; light just happens to move at _c_ in a vacuum. Light in other mediums like air and water moves slower than _c_. If light didn’t exist, _c_ would still be _c._ true enough - c is defined as the constant and is the value of ‘light speed’ in a vacuum - and the point still stands - that while you might slow light down in other mediums - light will never travel faster than light in the same medium. Is it possible our constant is ‘incorrect’ ? sure - unlikely - but possible - but it still stands that light will never be faster than light (in a vacuum). ---
**Author:** ![mythoughts](https://avatars.discourse-cdn.com/v4/letter/m/7993a0/32.png) [@mythoughts](https://boards.straightdope.com/u/mythoughts)\ **Post date:** [February 25, 2014, 12:37am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/25 "2014-02-25T00:37:06Z")
> [@Lemur866](#): > > Simpler experiment. > > A rocket ship travels between point A and point B at 50% of the speed of light. > > Exactly halfway there, it turns on headlights and tail-lights. Does the light from the headlights, with the boost from the spaceship already traveling at a high % of c, hit the detector ahead sooner than the light from the tail-lights hits the detector behind? > > Does light emitted from a traveling object travel faster in the direction of travel and slower in the opposite direction? > > If light always travels at the same speed, regardless of how fast it was going when it was emitted, what does that mean? > > We know that all experiments we can do show that light travels at the same speed coming or going. And for that result to occur–the invariance of the speed of light–other constants have to bend and stretch. Incorrect, I was caught out on that one too! No, the other constants do not bend, you didn’t mean constants there did you, they are constant you know. But what you mean is than inconstant time and length change. Except that it doesn’t, both they can’t explain the speed of light in your example because while they may help light coming from one direction to look right, but they make it even worse the other way. If you are moving with light so it seems to be moving too slow time dilation could slow your perception of time down making the light seems faster perhaps, fixed, but light coming at you too fast now appears to be moving faster! But that is still not the real reason. Because the consistency of the speed of light is an axiom of SR, which means it is an assumption, something assumed to be obviously true that the rest of the theory is based on. If it is assumed to be true, then it doesn’t need to explain it. Pretty tricky, I think I should assume I am president of the world and demand a high tax from everyone. Hey, you don’t have to prove a bold and counter intuitive assumption, Einstein said so! Sadly that is the case, a big big bluff. I can get many replies, negative replies, but none that achieve explaining what will happen in a consistent manner that does not break Relativity. And each reply added that is’t that is as good as saying: Yes, Relativity is broken, but that doesn’t mean you don’t suck somehow! ---
**Author:** ![mythoughts](https://avatars.discourse-cdn.com/v4/letter/m/7993a0/32.png) [@mythoughts](https://boards.straightdope.com/u/mythoughts)\ **Post date:** [February 25, 2014, 1:11am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/26 "2014-02-25T01:11:01Z")
> [@Frazzled](#): > > I think you’re obsessed with trying to find a way around C so you’ve created overly elaborate experiments. But the fact is, if you think you have a workable experiment then do it and let the results speak for themselves. History proves that science LOVES to be proven wrong - it’s where the major discoveries lie and advances our knowledge. But you have to prove your hypothesis with math and experimentation, none of which you’ve demonstrated thus far. Can you tell me when longish standing theory of physics has been accepted as being wrong (not just incomplete like the Bohr model not showing the electron as a fuzzy indeterminate wave function)? And history has shown a long history of persecuting scientists in old and modern times that descented even though they were proven right. The guy who tried to tell people about these invisible creatures that spread disease. Or in modern times the persecution of the guy who said it is Homocystine not Cholesterol that was the major factor in heart disease, now increasingly considered correct, he and is family almost starved as no one would hire him. Sure, once it has happened the new model will be embraced, but don’t think scientists want to admit 109 years of science has been embarrassingly on the wrong course until we get there! Like trying to intervene in the drug use of a meth addict, if they ever clean up for good they may love you for the life saving intervention, but until then avoid them if they are holding anything sharp! > [@](#): > > Consider the galaxies at the far end of what we can see in the universe. Those galaxies are moving away from us at close to the speed of light due to expansion of the universe. The light that hits us from those galaxies is still measured at C. The difference is that the light is “red shifted” - the light from those galaxies is so far shifted that the light is no longer in the visible spectrum, it’s in the radio spectrum. If something was approaching us close to the speed of light the light would be blue shifted, but still coming at us at C. > > I think this is where you get confused - I think what you would see would be light shifted from red to blue, not speed differences. No, that is not confusing, I understand everything you just said. Though I still argue that it does not work when you get to the finer details, if light has a definite agreed upon location in space to all observers in any moment in time (all observers at that location would detect it simultaneously no matter their state of motion/acceleration) then SR fails by not even attempting to explain how that can happen, even as an axiom it fails by being an absurd one. But the broad strokes seem fine. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [February 25, 2014, 1:24am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/27 "2014-02-25T01:24:45Z")
> [@mythoughts](#): > > And if a mistake has pulled wool over everyones eyes for so long, how can we let anyone know we are on the wrong track now? What do you mean “we” Paleface? ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [February 25, 2014, 1:30am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/28 "2014-02-25T01:30:38Z")
> [@mythoughts](#): > > And history has shown a long history of persecuting scientists in old and modern times that descented even though they were proven right. > The guy who tried to tell people about these invisible creatures that spread disease. Which “guy” did we persecute? Redi, van Leewanhoek, Semmelweis, Pasteur, Lister? > [@](#): > > Or in modern times the persecution of the guy who said it is Homocystine not Cholesterol that was the major factor in heart disease, now increasingly considered correct, he and is family almost starved as no one would hire him. [Jury’s still out on](http://en.wikipedia.org/wiki/Hyperhomocysteinemia#Effectiveness_of_lowering_Homocysteine) the benefit in trying to fight high levels directly, so it’s possibly a nice screening tool but not necessarily a fix. Needs more research. Got a cite on the “guy” who discovered this and how no one would hire him? And I hate to tell you, but it’s really easy to starve in science, because getting grant money even for **proven** research areas is a bitch and a half, and I say that from experience. Know what? This just means science works. We [del]“persecute”[/del] criticize all research. We have to test and retest stuff, with multiple researchers and in different labs and such, before we accept it wholeheartedly and jump in with both feet. Insufficient research means you risk stuff like [thalidomide being used in pregnant women](http://en.wikipedia.org/wiki/Thalidomide#Birth_defects_crisis) without sufficient testing, and causing massive birth defects - something that a pharmacologist in the US FDA managed to avoid happening in the US when she insisted further testing was needed before approval. (Thank goodness you’re just going on and on about the speed of light rather than able to actually do something about implementing the physical change. 😉 ) ---
**Author:** ![standingwave](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@standingwave](https://boards.straightdope.com/u/standingwave)\ **Post date:** [February 25, 2014, 1:42am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/29 "2014-02-25T01:42:45Z")
> [@Ferret\_Herder](#): > > Call me crazy, but submitting to a peer-reviewed scientific journal is a pretty neat means of doing stuff like that. Unlikely that it would be published because, sadly, the world has more respect for the status quo than it has a love for the truth. Intellectual dishonesty and zealot are the name of the game. Better to write a letter to the [President of Physics](https://xkcd.com/675/). ---
**Author:** ![mythoughts](https://avatars.discourse-cdn.com/v4/letter/m/7993a0/32.png) [@mythoughts](https://boards.straightdope.com/u/mythoughts)\ **Post date:** [February 25, 2014, 2:10am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/30 "2014-02-25T02:10:45Z")
> [@Simplicio](#): > > Einstein had a PhD in Physics Yes, But I thought they were all Honorary. Looking it up, it is only clear he did poorly in school (and was home-schooled) and has Honorary degrees. It is not clear if he actually attended classes or did tests and the like to gain a degree earned. Maybe he did though? But I had heard he didn’t. update: Ok, it seems he did attend a college. ---
**Author:** ![Simplicio](https://avatars.discourse-cdn.com/v4/letter/s/c37758/32.png) [@Simplicio](https://boards.straightdope.com/u/Simplicio)\ **Post date:** [February 25, 2014, 2:18am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/31 "2014-02-25T02:18:51Z")
> [@mythoughts](#): > > Yes, But I thought they were all Honorary. > > Looking it up, it is only clear he did poorly in school (and was home-schooled) and has Honorary degrees. > It is not clear if he actually attended classes or did tests and the like to gain a degree earned. > > Maybe he did though? But I had heard he didn’t. Where did you look it up? The wikipedia article on Einstein details on Einsteins early life and academic career. None of the things you posted here appear to be true. ---
**Author:** ![mythoughts](https://avatars.discourse-cdn.com/v4/letter/m/7993a0/32.png) [@mythoughts](https://boards.straightdope.com/u/mythoughts)\ **Post date:** [February 25, 2014, 2:26am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/32 "2014-02-25T02:26:36Z")
> [@Ferret\_Herder](#): > > Which “guy” did we persecute? Redi, van Leewanhoek, Semmelweis, Pasteur, Lister? Ignaz Semmelweis > [@](#): > > Got a cite on the “guy” who discovered this and how no one would hire him? Google: Dr. McCully, homocysteine and Harvard. ---
**Author:** ![mythoughts](https://avatars.discourse-cdn.com/v4/letter/m/7993a0/32.png) [@mythoughts](https://boards.straightdope.com/u/mythoughts)\ **Post date:** [February 25, 2014, 2:38am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/33 "2014-02-25T02:38:41Z")
> [@Simplicio](#): > > Where did you look it up? The wikipedia article on Einstein details on Einsteins early life and academic career. None of the things you posted here appear to be true. That he did poorly in school is both well known and turned up in my search. Maybe it is an urban legend but it is a pretty common one. Here are examples of people trying to answer that question. Plenty of them say honorary only, and he did poorly in school > **[Yahoo Search - Web Search](https://search.yahoo.com/)** > > The search engine that helps you find exactly what you're looking for. Find the most relevant information, video, images, and answers from all across the Web. > **[Yahoo Search - Web Search](https://search.yahoo.com/)** > > The search engine that helps you find exactly what you're looking for. Find the most relevant information, video, images, and answers from all across the Web. > **[Yahoo Search - Web Search](https://search.yahoo.com/)** > > The search engine that helps you find exactly what you're looking for. Find the most relevant information, video, images, and answers from all across the Web. > **[Yahoo Search - Web Search](https://search.yahoo.com/)** > > The search engine that helps you find exactly what you're looking for. Find the most relevant information, video, images, and answers from all across the Web. And: In 1895 Albert Einstein’s teacher said to his father: “It doesn’t matter what he does, he will never amount to anything.” ---
**Author:** ![Simplicio](https://avatars.discourse-cdn.com/v4/letter/s/c37758/32.png) [@Simplicio](https://boards.straightdope.com/u/Simplicio)\ **Post date:** [February 25, 2014, 2:48am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/34 "2014-02-25T02:48:55Z")
Yahoo answers is basically a of random bored people guessing. I’d strongly recommend against using it for anything. Einstein attended primary and secondary school in Germany. He got a teaching degree and then a PhD in Zurich. He got decent marks in school, and while he failed an entrance exam for the secondary school he wanted to get into, seems to have had a generally successful, if not exactly stellar, pre-relativity academic career. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [February 25, 2014, 3:05am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/35 "2014-02-25T03:05:51Z")
> [@mythoughts](#): > > Plenty of them say honorary only, and he did poorly in school People say lots of things that aren’t true. Einstein got his doctorate (a real one) from the University of Zurich in 1905. ---
**Author:** ![cerberus](https://avatars.discourse-cdn.com/v4/letter/c/71e660/32.png) [@cerberus](https://boards.straightdope.com/u/cerberus)\ **Post date:** [February 25, 2014, 3:32am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/36 "2014-02-25T03:32:50Z")
It would be awesome if there were some sort of natural mode of language amenable to the discussion of physics. Mathematics? ---
**Author:** ![mythoughts](https://avatars.discourse-cdn.com/v4/letter/m/7993a0/32.png) [@mythoughts](https://boards.straightdope.com/u/mythoughts)\ **Post date:** [February 25, 2014, 3:42am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/37 "2014-02-25T03:42:23Z")
For those who don’t bother to read the experiment, here is a shortened version. For brevity, I will explain it essentially in one sentence. and the possible results in a few more, But the longer form solves questions and objections: Take 2 light sensors separated at an appropriate distance, the censors are shaped like CD and are transparent, designated A and B, rotate them at high enough velocity so that the time dilation associated with General Relativity (GR) applying (gravitational equivalence time dilation) can be measured, and let sensor A send a signal to both clocks, and sensor B also sends a signal to both clocks. If we expect light to be seen as C (assuming a vacuum) by both clocks we have a problem since there are only 2 sensors, not 2 sets of sensors and one close is slow. If light is somehow seems to be moving less than C by the non time dilated clock, then if additional non-rotating sensors A2 and B2 are placed right next to sensors A and B less than a mm apart then we would then expect to find these sensors A2 and B2 to give the right answer to our normal clock to get the expected velocity? But then censors B and B2 which are almost in the same exact place would not see the photon at the same time, the second sensor B2 would see it first, and later the slightly closer censor would! And it gets worse, from the rotating sensors and rotating clocks view light is not taking the most direct path between the 2 censors, it is on an angle, so the light is moving further in the rotated (slow clock) frame and doing it in less time than the shorter distance would be expected to take provided you assume that the previous example of B2 detecting something before the ever so slightly closer B censor is not possible. About the only half way sensible way out of these impossibilities is to assume that all the space between any 2 co-moving objects that could be measuring light also gets time dilated?? And that is the most sensible but still obviously wrong conclusion I can find. If you object that the time dilation means finding light the be faster than C is fine, then read on, but note that even without time dilation the light would still exceed C from taking a longer path… ---
**Author:** ![Yumblie](https://avatars.discourse-cdn.com/v4/letter/y/76d3ee/32.png) [@Yumblie](https://boards.straightdope.com/u/Yumblie)\ **Post date:** [February 25, 2014, 3:52am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/38 "2014-02-25T03:52:48Z")
> [@mythoughts](#): > > That he did poorly in school is both well known and turned up in my search. > Maybe it is an urban legend but it is a pretty common one. > > Here are examples of people trying to answer that question. > Plenty of them say honorary only, and he did poorly in school > > [Yahoo Search - Web Search](http://answers.yahoo.com/question/index?qid=20091022065543AA6ljqb) > [Yahoo Search - Web Search](http://answers.yahoo.com/question/index?qid=20081209175757AAXFfEk) > [Yahoo Search - Web Search](http://answers.yahoo.com/question/index?qid=20080519070911AAa5BU9) > [Yahoo Search - Web Search](http://answers.yahoo.com/question/index?qid=20100423232358AARKtFE) > > And: In 1895 Albert Einstein’s teacher said to his father: “It doesn’t matter what he does, he will never amount to anything.” Einstein didn’t do poorly in school. His primary school teachers hated him because he had a bad attitude toward authority, likely because school bored him. He got excellent grades, _especially in mathematics_. Why does everyone want to disprove relativity? There are lots of other areas of physics that are on far shakier ground than relativity. If you can find an exception to the speed of light rule, you not only break relativity, but you break all of quantum physics as well. It’s not impossible, but it’s going to take more than a few thought experiments to undo decades of actual, physical experiments. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [February 25, 2014, 4:08am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/39 "2014-02-25T04:08:19Z")
> [@mythoughts](#): > > . . . Take 2 light sensors separated at an appropriate distance, the censors are shaped like CD and are transparent, designated A and B, rotate them at high enough velocity so that the time dilation associated with General Relativity (GR) applying (gravitational equivalence time dilation) can be measured, and let sensor A send a signal to both clocks, and sensor B also sends a signal to both clocks. . . . Rotate them, how, exactly? And where are the clocks? Are the clocks part of the sensors? You say, “Send a signal to both clocks,” but that is the first mention in your set up of clocks at all. What does the shape of the sensors matter? They could be shaped like rubber duckies. Why “shaped like CD?” Why are they transparent? What does that matter? They could be opaque, and colored green. You’re putting in unnecessary details…and leaving out necessary ones! ---
**Author:** ![Count\_Blucher](https://avatars.discourse-cdn.com/v4/letter/c/c5a1d2/32.png) [@Count\_Blucher](https://boards.straightdope.com/u/Count_Blucher)\ **Post date:** [February 25, 2014, 4:15am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/40 "2014-02-25T04:15:46Z")
> [@cerberus](#): > > It would be awesome if there were some sort of natural mode of language amenable to the discussion of physics. > > Mathematics? Mathematics as a discussion is at best… difficult. Still, it makes a nice dictionary to a physics-esque game of conversational Scrabble. 😉 ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [February 25, 2014, 4:29am UTC](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160/41 "2014-02-25T04:29:50Z")
Have light’s mother shame him. [Previous page](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160.md?page=1) [Next page](https://boards.straightdope.com/t/how-to-have-light-move-faster-than-c/682160.md?page=3)