Vision at lightspeed?

[sundog]

Hello all

 

My first post, so here goes.

 

I'm interested to know what would be seen as you accelerate to near light speed (if it were possible).

 

I read somewhere once that your eyes would intercept photons from stars to the side of your direction of travel, so your peripheral vision would close in like a tunnel, in effect, what you would see in the corner of your eyes while at rest would be brought to the front of your vision at speed.

 

I can kind of understand this idea, but what about the red shift effect where light from a source moving away from you is slightly shifted to the red end of the spectrum.

 

With this in mind, I tend to think that maybe as you accelerate, everything in front of you would blue shift. Therefore emissions in infra red would become visible as normal red. Emissions in blue or violet would shift into ultra violet thus becoming invisible to us. So would you see the stars and nebulas change color?

 

Would it be a mix of the two ideas?

 

Would the stars stretch, a la 'star trek'?

 

Am I making sense?

 

 

Thanks

 

sundog

[alexander]

You kind of make sense, but i think that you might want to reconsider your color theory...

Another color theory:

I think that instead of your color vision shifting you would instead observe a totally different effect. But first going back to basics: ok, color is nothing more than the reflection of light from the surface area of an object which surface has an ability to "suck up" stop or slow down one or more frequencies of the color wave. Now, taking aprism, and passing light through it you will see a rainbow, or a spectrum of colors making up light (in out case sunlight). The spectrum goes from blue to red and everythin in between. Yet there are colors that we miss in a linear color spectrum, for example magenta or actually all pink related colors. In order to get pink what we need to do is loop the linear spectrum over 360 degrees and what do we get? That's right, a new color. Ok now to the hypothetical part: if by inscribing a linear color spectrum into a 2 dimensional color spectrum we get a new color that we could not recognize before, if we were to add a 3rd dimension we would get ever new colors that we were unable to identify before. Now, if you beleive in 4th dimension being time, and by entering a wormhole, or straight accelerating to the speed of light would bring you to a speed at which you'll be able to observe the dimension at work, a dimension that keeps on moving, then following the precedent set by examples above, wouldn't you if putting our 3d spectrum into the 4th dimension create a new color? But if the 4th dimension progrsses, wouldn't the color progress along with a dimension? Meaning that as the 4rth dimension changes, wouldn't the color change with it, creating an infinite ammount of colors. Or perhaps that at the light speed you will be able to observe the repetition of the change, thus momentarily proving that we live in an infinite loop of time, and our universe would only be able to take so many loops before crashing, thus proving the possibility of Big Bang....

[Freethinker]

Color is a figment of our imagination. It does not exist in nature. Light (photon/ wave/ particle) travel at a given speed. The wave function fluctuates/ vibrates/ ripples... at various speeds. Thus we get various electromagnetic frequencies. Our eyes are non-linear transducers. They only pick up a narrow band of these frequencies and we are not as sensitive to some freqs as we are others. Further there are various elements in our eyes that respond to different frequencies and not others. It is the data that comes from all of the various different elements in our visual system that are compiled in our minds to "create" what we call color. But in nature all there is is varied amplitudes at various frequencies. There is no "color" as such. We see luninance levels (brightness) with frequency info added in our brains to give a subjective image.

 

Magenta IS part of the frequency spectrum, but not as a single frequency. It is a combination of two freqencies (red and blue). Pink is red as far as freq, but contains some levels of blue and green to raise the general luminance level. So the magenta and pink issues are NOT related to some looping of anything. Nor is there any "360 degrees" involved with color spectrum. Red is at the lower end of the visible frequency range and blue the upper end. It doesn't "loop" anywhere. It goes down in freg from red, into freqs we do not SEE (though we can FEEL some of it as heat) and it goes up from blue to freqs we can not detect.

 

One answer to what would we SEE if we were traveling at the speed of light would be "nothing". We would not survive the acceleration.

[sundog]

Freethinker,

 

you said "One answer to what would we SEE if we were traveling at the speed of light would be "nothing". We would not survive the acceleration"

 

you are quite right of course, that's why I said "IF" it were possible.

 

Thanks for your explanation of color, this is also how I understand it. I was baffled by the idea Alex gave about looping linear spectrum over 360 degrees. I thought maybe I was misinterpreting what he was trying to say or just lacked knowledge on some aspect of light. (there's much in science/physics that go way over my head). Anyway...

 

I have found a site with an answer.

But bare in mind the main page states "Its purpose is to provide good answers to questions that have been discussed often in sci.physics and related usenet newsgroups. The articles in this FAQ are based on those discussions and on information from good reference sources. That does not mean that they are always perfect and complete."

 

 

This following link gives a brief overview with images of what you would see, according to the theory of special relativity.

 

http://math.ucr.edu/home/baez/physics/Relativity/SR/Spaceship/spaceship.html

 

It is (according to the above site) a mix of effects: Doppler shift (or red shift), Aberration (the tunnel effect, as I poorly explained it) also "Beaming" (brightening of light due to increased flux intensity.

 

Here's an excerpt -

 

"Starlight consists of light in a wide range of wavelengths, so while it is true that an approaching star will have its light Doppler shifted into shorter wavelengths (except for very high and inclined velocities), 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."

 

"Considerations of the flux lead to what is generally called beaming. Beaming is related to aberration in that flux intensity is increased in the forward direction due to the squeezing of the total flux. In addition, 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."

 

Well I was on the right track it seems, although I had not thought about the stars getting brighter. Well I am only a lay person striving to get a better concept of these things

 

Anyone else have a different (or additional) idea of what you might see?

 

 

 

I'd just like to say Thank you to Tormod for hosting these forums. There's some fascinating topics here. Much food for thought.

 

Thanks

 

sundog

[Freethinker]

Originally posted by: sundog

Freethinker,

 

you said "One answer to what would we SEE if we were traveling at the speed of light would be "nothing". We would not survive the acceleration"

 

you are quite right of course, that's why I said "IF" it were possible.

 

I just like being a wise *** once in a while. :-)

 

 

Thanks for your explanation of color, this is also how I understand it. I was baffled by the idea Alex gave about looping linear spectrum over 360 degrees. I thought maybe I was misinterpreting what he was trying to say or just lacked knowledge on some aspect of light. (there's much in science/physics that go way over my head). Anyway...

 

My guess was he has familar with color tables shown for color displays. Esp the "color picker" which tends to be circular. It is typically based on a HSV system Hue, Saturation and Value. Hue being the color (as identified by it's vector around the wheel, thus perhaps the "looping around") Saturation being how strong the color and Value how bright. In TV they also show color based on a similar "Vector" display. In it, Magenta resided between red and blue, which of course we know it can't in a linear (logarithmic actually) color scale.

 

It is (according to the above site) a mix of effects: Doppler shift (or red shift),

 

"Starlight consists of light in a wide range of wavelengths, so while it is true that an approaching star will have its light Doppler shifted into shorter wavelengths (except for very high and inclined velocities), 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."

 

Yes, in a true blackbody radiator (white light source) the energy is spread evenly across the spectrum. Doppler shifting would not be noticable. The entire smooth spectrum would shift and there would be nothing to serve as a marker of it happening. Star light has markers in it. There will be brightness differences, appearing as dark bars in a spectrum anaylzer which correlate to specific elements. e.g. Carbon has a specific signature of bars when it is heated. By knowing the various widths and seperations of the bars, as the frequency is shifted red or blue, the bars width and relative seperations will stay the same. The frequency reference points of the bars will have shifted though. And that is how you can tell the relative speed.

 

This is why I understood in General Relativity that the speed of light was constant, even at the speed of light. At least relative to light waves infront or behind. But the cone would narrow to the sides as you approach the speed of light.

 

I just did not want to step out on the limb with this one. I don't like making claims unless I check things out first. Just to keep the ole brain in line.

 

So I make wise *** cracks instead. Like my last post :-)