Speed of Light

[MarkyP05]

If i were to be travelling at the speed of light would i be able to see any other light around me, and would any light visable to me matter if it was based behind , in front or to the side of the direction i was travelling in.

[mimififi]

Don't know? Would you be able to see the light in all its different colours? An interesting question. What would happen if you were in a car travelling at the speed of light and then switched on the headlights ????

I eagerly await replies also.

[Space]

I don't think you would be able to see anything if you were travelling at the speed of light, because time would "stop" for you. Your body would stop ageing and not feel anything. You wouldn't even notice how long your journey lasts.
But then I don't know if it's even possible to travel at that speed.

I wonder what happens if you travel at 90% of the speed of light though...
I suppose you still see light but colors would be shifted.
For example, stars in front of you would seem blue, and those behind you would be red.
(This is just my guess)

[fo3nix]

the question is pointless, because you cannot travel at the speed of light.

[CT]

As you approach the speed of light (in theory) the stars around you would appear to shift closer to point which you are travelling towards. So, if you could look all around you, the stars in the direction from which you are travelling would appear to spread out. The closer to the speed of light you get, the closer paked the stars would become.

[Clanad]

As an overly simplified answer and in accordance with Einstein's special theory of relativity  which states that uniform, non-accelerated motion has no meaning of and by itself. That is, there is, by assumption, no meaning to the idea of moving uniformly at the speed of light in an empty universe. That state is completely equivalent to being at rest in an empty universe. Suppose�to make things easier to understand�that the speed of light is a hundred miles an hour. Now suppose you are standing by the side of the road and see a light beam pass by at this speed. Then you see someone chasing after it in a car at sixty miles an hour. To you, it appears that the light beam is outpacing the car by forty miles an hour. But, the person inside the car must see the beam escaping ahead at a hundred miles an hour, just as one would if one were standing still:  So states Einstein. What if the person guns the engine and speeds up to ninety-nine miles an hour? Now you see the beam of light outpacing the car by just one mile an hour. Yet to the person inside the car, the beam is still racing ahead at a hundred miles an hour, despite his increased speed. Hmmm? you say. Speed, of course, equals distance divided by time. Evidently, the faster one goes in their car, the shorter their ruler must become and the slower their clock must tick relative to mine; that is the only way we can continue to agree on the speed of light. (If I were to pull out a pair of binoculars and look at the speeding car, I would actually see its length contracted and the person inside moving in slow motion.) So, the lights you see while travelling at this speed (impossible, of course) would appear "normal".

Contd.

 

[Clanad]

Mimififi's concept isn't really that far off when the affects of Doppler Shift and Beaming are considered. Again, simply put, if our speed is nearing c out in space,  an approaching star will have its light Doppler shifted into shorter wavelengths, but it is not necessarily true in general that the star will show a bluer colour.  The reason is that the whole spectral energy distribution is shifted, so that a previously invisible infrared part may contribute considerably to a redder colour, and similarly, light from the blue part of the spectrum may be shifted out to the invisible UV. (Thanks to Aleix Brandeker, Physics FAQ). 

Beaming explains that the intensity of the star's light may well be affected, though.  If we consider a steady stream of photons, they tend to arrive more often if one travels towards the source, and less often if one recedes.  This results in higher flux intensity, and causes stars in front to get brighter, and from rear to get fainter.

[mimififi]

Clanad, I would post again, but I'm lost for words. This is me lost for words............................................
.................
...
.........................

How do you know so much?????
(and that is a serious question, I'm not just being a cheeky monkey there, seriously!)

[Clanad]

mimififi, the lady of this house for whom I perform house maintenance duties, gardening, cooking, car repair, livestock care, tractor maintenance, pet care, horse care and a whole list of other duties in exchange for sleeping privileges, says I'm a walking compendium of absolutely useless facts.  Actually, my profession and early upbringing caused a fascination with "things".  Many times, a question will trigger a long dormant bit of knowledge for some reason.  Additionally, I never participate in "advice" types of questions.  In some cases, such as the answer I provided here, I relied on an informal study of relativity done during a study of Geology at a western University, but new facts have been added, hence my attribution to Proffesor Brandeker.  I use good judgement on picking disputes with the likes of Quizmonster (affectionately known as Q) though... It's my firm belief that one is never too old to learn... Thanks for the inquiry, though...

[mimififi]

Wow, clanad, you're some machine....It's just about all I can do to remember to eat breakfast (then again, I have about amillion children and they have captured my brain cells and are holding them to ransom!)

Keep it up.  I always enjoy reading your posts.

P.S.  Have you ever posted an actual question on AB?

[Greeno]

Not 100% sure about this but the colours wont change. We see colours by registering different wavelengths being reflected by certain materials. If you were to travel at the speed of light things to the side of you would appear the same. Images in front of you would appear the same but there would be a shorter time delay between them happening and you seeing them. Behind you things would be more and more delayed until straight behind you it would seem like time has stood still and nothing would move as the light rays/particles would be travelling at the same speed so newly reflected rays/particles wouldnt reach you. As i said i'm not 100% sure!

[mibn2cweus]

Regardless of our speed in a given direction light photons continue to move towards or away from us at the same speed, however there energy, (and therefore there color), is effected by our relative motion.  This mimics the Doppler effect of sound of which most of us are familiar. 
We are now actually able to observe some of these phenomena.  With powerful space based telescopes we are able to observe light from billions of light years distance. One observation is that as we look further into the past we see the universe is expanding due to light color shift toward the red as we look deeper into space. This phenomenon is also apparent in observing star pairs which are evidently rapidly revolving around each other as there again we observe color shift.

[NetSquirrel]

Ok, sorry, I usually just keep quiet when Clanad posts an answer that he has *obviously* plagiarised from elsewhere, but this is too much.  Please take a look here and tell me if I am out of line in my accusations.  I don't mean to point the finger at Clanad all the time, but most of his "amazing knowledge" is simply lifted from the work of others, with little attempt to disguise the act.  And almost never do I see Clanad give credit to the actual author (unless he suspects that I am "on to him" as he may do now, and therefore mend his ways for, say, a week or two).  It is not the giving of a detailed and relevant answer that bothers me (if only more of us put the Google hours into it that Clanad does), but the fact that he is ripping off the work and ideas of greater minds and claiming them as his own, which I always believed was against AB policy, not to mention downright immoral. 

 

That URL again: http://ny-2.live.advance.net/printable/?critics/050228crat_atlarge

Here's hoping I don't get banned for this...

[mibn2cweus]

Numbers 32:23 (King James Version)  Public Domain
But if ye will not do so, behold, ye have sinned against the LORD: and be sure your sin will find you out.

[Clanad]

Ah... netsquirrel, haven't seen you for ages. Welcome back.  I'm impressed that you have nothing better to do than to Google all the possible sources for information. Actually, it wasn't Tim Holt's review that caught my attention, although the metaphor about a car and its light was excellent, it was an excerpt of this contained in yet another publication and was simpler and easier to understand than the one I was attempting to construct.  Actually, somehow, you missed my attribution to Professor Alexis Brandeker, but that's not entirely unheard of in your past criticisms.

My original reference was obtained from http://www.motionmountain.net/C-2-CLSC.pdf if you'd like to review it.  I'm unclear on what it is you think I have to gain by posting informative, factual responses to questions posted herein.  If I were selling them, then you would have grounds to cast aspersions.  As it is, I don't see any enlightening tidbits with your name attached to them.  Perhaps we could discuss weight and balance shift in the Boeing 727 during flight at mach .82, or pruning requirements for the three varietals of Clematis.  Rest assured, I didn't orignate those ideas either.  But isn't the sum total of our knowledge, other than researchers, gained from others anyway? Again, welcome back!

[NetSquirrel]

Clearly, then, the only logical explanation is that I must have, against all odds, caught you at exactly those times when it "slipped your memory" to credit your sources.  Conveniently, I can Google all instances of the words "NetSquirrel" and "Clanad" cropping up in the same thread, which results in the followling list of all the times (not including now) that I have lost my temper with you:

Feb 05
March 05 (i) 
March 05 (ii)

Funny...there must be more than that, surely?  Anyway, there are two points I must concede to you before I continue.  Firstly, I did overlook your reference to Brandeker, and secondly, your observation that most [advanced] knowledge is gleaned from others is perfectly valid.

My basic problem is that most of us simply can't distinguish a genuine Clanad answer from one that appears as such but for an inconspicous "With help from..." at the end.  Or, more commonly, just three dots - "..." - to indicate a Googled answer, or the classic no-hint-at-all.  It is more conventional, and much clearer, to place all copied material within single or double quotation marks, convert to italic, and credit your source underneath.  E.g.

"Actually, my profession and early upbringing caused a fascination with "things"."

- Clanad

[Continued]

[NetSquirrel]

As for what you have to gain, well only you can truly know that.  But if I am not mistaken, the respect and admiration of ones peers are often much sought after, are they not?  This being the AnswerBank, praise is handed to whoever responds with the best answer, and praise feeds the ego.  If truth be told, it's what motivates us all.

Reading back, I realise I may have exploded on you over quite a petty offence, but please, separate your words from your sources or we don't know who's saying what.

[Clanad]

So, netsquirrel let me be sure I understand... you object to the style I employ to construct answers as well as define attribution.  Everyones style must comport with yours to be valid.  Hmmm, unique concept.  Do you check other's style or only mine?

As to what I may gain... "respect and admiration of one's peers"... Let's be a little realistic here... you and me are both a series of 1's and 0's... there's no possible way I could gain 'respect and admiration' from anyone (nor do I seek either). I live half a world away, for one thing. I do enjoy posting answers to those relatively few questions within a relatively narrow scope, on some of which I refresh my memory and understanding by reference.  Many times, if you care to check, I leave, as do many others, only a web link.  Fact is, most people whose questions are answered don't respond with anything other than a cyber shrug of the shoulders... and that's OK to, as far as I'm concerned.  I think you may need to examine your motives.  I've not received criticism from other sources and your's seems to me to border on the obsessive.  This is, after all, basically an entertainment site.  Finally, I would disagree, at least in my view, that praise is what motivates me, but then I can only speak for myself.  At any rate, have a nice evening...

[NetSquirrel]

Please, I know you are intelligent enough to understand that I did not mean to criticise your "style" - nor anyone else's - unless plagiarism is considered a style.  And don't try to bundle yourself in with a larger group (a classic defence mechanism):

"Everyones[sic] style must comport with yours to be valid.  Hmmm, unique concept.  Do you check other's[sic] style[s] or only mine?"

Scroll up to mimififi's comment ("How do you know so much???")  In your response, you imply that your answer is your own work, but with "new facts" courtesy of Professor Brandeker.  Now, most people are going to understand this to mean: oh, Clanad wrote that answer himself, but got some of his information from Brandeker.  The real case is that you copy-pasted Brandeker's words and merged them with your own, to make the whole passage appear as your own.

Now, you have made it very clear that you consider this a minor point, a mere technicality, but it is not so to me.  Please see here for an accurate definition of plagiarism, taking particular note of the paragraph beginning "Note that if the writer had used these phrases..."

[Continued]

[NetSquirrel]

I stand by my opinion that I believe you do this to enhance your image and win the approval of fellow ABers (it's basic human instinct and I can hardly blame you for it). And this tactic has worked for you most of the time, yielding plenty of ego-boosting compliments; but if, like you said, praise is not what motivates you, then one can only surmise that you do not realise when you are quoting a source, and when you are plagiarising.  Certainly, you did not draw the distinction when you so modestly replied to mimififi's comment.  If this is indeed a simple case of misunderstanding, then I apologise for my harshness.

Well...we could probably continue our exchanges until the AB Ed politely asks us to spare their bandwidth, but I think I will call an end to the pettiness, at least for myself.  And as for who else's answers I "check", well, I do it in your case whenever an answer seems, shall we say, "un-Clanad-ish", and you make take that as you like.

[blinkyblinky]

In my humble opinion (and if you don't want to know it, skip the next paragraph)...

It seems a bit naughty of Clanad to segue from his own words into the lifted piece without making it clear, and especially to receive the compliments from mimififi without mentioning the fact.

Can somebody just give me a quick explanation of why, if you are traveling at 60 mph chasing light traveling at 100mph, the light seems to be moving away at 100mph? Surely it would appear to be moving at 40mph (100 - 60 = 40). Obviously I'm missing something.