# Why is light speed the limit? **URL:** \ **Category:** Factual Questions\ **Created:** [December 30, 2003, 10:48am UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742 "2003-12-30T10:48:52Z")\ **Posts on this page:** 10\ **Page:** 3
**Author:** ![MC\_Master\_of\_Ceremonies](https://avatars.discourse-cdn.com/v4/letter/m/bb73d2/32.png) [@MC\_Master\_of\_Ceremonies](https://boards.straightdope.com/u/MC_Master_of_Ceremonies)\ **Post date:** [January 1, 2004, 5:30pm UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/41 "2004-01-01T17:30:23Z")
With a wormhole the speed locally never exceeds the speed of light. Infact in genral relativity special relativity only really applies locally. ---
**Author:** ![askol](https://avatars.discourse-cdn.com/v4/letter/a/53a042/32.png) [@askol](https://boards.straightdope.com/u/askol)\ **Post date:** [January 1, 2004, 11:21pm UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/42 "2004-01-01T23:21:26Z")
**Ring** , in my solid-state electronics course we talked about the longitunidal and transverse masses of free electrons in semi-conductor crystals - but then again, we also talked about the longitudinal and transverse masses of an absence of an electron, so I guess it is a silly idea. 😛 ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [January 2, 2004, 1:56am UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/43 "2004-01-02T01:56:01Z")
It’s not really a silly idea it’s more of an outmoded idea. The concept of relativistic mass can be very confusing as can be readily seen from the many posts on this board claiming that the gravitation of a massive object increases as its velocity increases. **Askol** you might find it interesting that relativistic mass is equivalent to transverse mass – not the longitudinal mass as I think most people would guess. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [January 2, 2004, 2:05am UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/44 "2004-01-02T02:05:11Z")
> [@](#): > > \*Originally posted by eburacum45 \* > \*\*In our imaginary SF universe wormholes are permitted, as they may be in the real universe; > however if the configuration of the wormholes ever approach the state where time travel and closed timelike curves are possible, one or both of the wormholes collapse. > > This does not occur as the wormholes arecarefully controlled. > > FTL travel is therefore enabled by geometry. > > [http://www.orionsarm.com/main](http://www.orionsarm.com/main) \*\* It’s possible to have FTL communication or travel under “constrained” circumstances- that is, you carefully limit when and where FTL is permitted so as to avoid the classic paradoxes. But doesn’t that abolish the axiom of “no privileged frames”? In other words, what’s to stop someone ffrom creating a second FTL link that closes a time loop? ---
**Author:** ![DanBlather](https://avatars.discourse-cdn.com/v4/letter/d/f4b2a3/32.png) [@DanBlather](https://boards.straightdope.com/u/DanBlather)\ **Post date:** [January 2, 2004, 3:26am UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/45 "2004-01-02T03:26:21Z")
> [@](#): > > \*Originally posted by chaoticdonkey \* > \*\*I thought of an exception ot the speed of light = max for anything, ever theory today. Imagine a mirror. Move that mirror towards a point-source of light. Shouldn’t the velocity of the resultant beam be \>C? \*\* Yes, logically it should, but it isn’t. The return beam will be at C but it’s frequency will be blue shifted. ---
**Author:** ![Bookkeeper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bookkeeper/32/281_2.png) [@Bookkeeper](https://boards.straightdope.com/u/Bookkeeper)\ **Post date:** [January 2, 2004, 5:42am UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/46 "2004-01-02T05:42:20Z")
IIRC the blue glow seen around water-moderated reactors (“swimming pool” types) is caused by particles exceeding the speed of light (which is slower in water than in vacuum). So it is possible to exceed “the speed of light” but not to exceed **C**. ---
**Author:** ![DanBlather](https://avatars.discourse-cdn.com/v4/letter/d/f4b2a3/32.png) [@DanBlather](https://boards.straightdope.com/u/DanBlather)\ **Post date:** [January 2, 2004, 5:48am UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/47 "2004-01-02T05:48:55Z")
> [@](#): > > _Originally posted by Bookkeeper \* > **IIRC the blue glow seen around water-moderated reactors (“swimming pool” types) is caused by particles exceeding the speed of light (which is slower in water than in vacuum). So it is possible to exceed “the speed of light” but not to exceed**C_\*. \*\* Cherenkov radiation, the blue glow, is cuaed by particles exceeding the speed of light in water. ---
**Author:** ![MFitz](https://avatars.discourse-cdn.com/v4/letter/m/ce7236/32.png) [@MFitz](https://boards.straightdope.com/u/MFitz)\ **Post date:** [January 2, 2004, 9:05am UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/48 "2004-01-02T09:05:00Z")
I always find it funny when someone says that relativity is “the way it is”. If it were correct, quantum mechanics and cosmology would mesh and there would be a unified field theorem. There isn’t. Ergo, it’s not “the way it is”. Even Superstring theory is a mathematical nightmare. It’s certainly interesting stuff, and it has the multi-dimensional components that I think has a certain appeal, but None of these theories are right. Ever watch an old Nova program? The “experts” often talk about how the unified field theory will be found in the next few years (80s, 90s, etc.) Usually, these are only math nerds convinced that what they love is the ultimate solution to everything. (I remember reading a hysterical article in Japan about a man who figured out how to tell everything about a person’s personality by their teeth. The article was, of course, written by a dentist.) Bottom line: We all know what a circle is, but they don’t really exist. Mathematics is a tool whereby mental symbols represent reality. That only works in the “middle universe.” At the very small or very large, math breaks down. The solution is not going to be found by this species, maybe once we re-invent ourselves, but not by us. In the meantime, it’s only Menza society puzzles (useful for many things) but still just mental games. [For anyone who cares, read about how a recent discovery MAY show how the “light barrier” is regularly broken:](http://news.bbc.co.uk/1/hi/sci/tech/841690.stm) Just my 2 cents. MFitz ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [January 2, 2004, 1:03pm UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/49 "2004-01-02T13:03:28Z")
_originally posted by Lumpy_\*\* In other words, what’s to stop someone from creating a second FTL link that closes a time loop?\*\* Hawkings Chronological Protection Conjecture; the universe conspires to prevent time travel. it might happen that the creation of a closed timelike loop creates a virtual particle feedback effect, which extracts energy from the wormholes and makes them, or at least one of them, collapse. So you keep them far apart and all pointing away from your home system. [http://www.orionsarm.com/whitepapers/wormholes.html#4](http://www.orionsarm.com/whitepapers/wormholes.html#4) ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [January 2, 2004, 1:20pm UTC](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742/50 "2004-01-02T13:20:59Z")
Sending supraluminal waveforms withiin a beam of light does not break the speed limit; the light itself still only travels at lightspeed. That is just playing with harmnics in my opinion. In the same way the shadows within Hubble’s variable Nebula move faster than light- but they are only shadows. [http://www.psiaz.com/polakis/n2261/n2261\_1999.html](http://www.psiaz.com/polakis/n2261/n2261_1999.html) [Previous page](https://boards.straightdope.com/t/why-is-light-speed-the-limit/221742.md?page=2)