Can someone explain relativity to me?

[Traab]

Preferably in layman's terms. Why does traveling at the speed of light, or close to it, make time move slower for you than for the world around you?

[LaZodiac]

The...most laymen way I can explain it is that "gravity slows down time, and going fast increases the amount of gravity on you"

[BaronOfHell]

The premise is that the speed of light is the same for every observer (and that the laws of physics is identical for all speeds, but whatever). From there you can figure out the rest yourself.

Just to clarify, if you travel at the speed of .5 light speed, you'd observe a beam of photons travelling at exactly 1 light speed faster than yourself. So e.g. if it's relative to Earth you're moving at .5 light speed, you'd maybe think that those people down on Earth would see this light beam travel at 1.5 light speed (yours .5 plus the 1 faster than yourself which you're observing the beam travelling), but no they observe it at 1 light speed (0.5 light speed faster than you).

Since speed doesn't change as you'd think, distance and time has to in stead. From a view point of trying to eliminate paradoxes [cause and effect comes to mind], looking at the geometry of the system, etc. you can then figure out how distance and time should change from one speed to another.

[Silverrida]

Baron covered it basically perfectly. Kudos.

[BaronOfHell]

Thank you. :)

[factotum]

As I understand it, all the effects of Special Relativity (which is what you're talking about) derive from the fundamental realisation that nothing can ever travel faster than the speed of light. Everything else follows from that--for instance, if you could somehow keep accelerating indefinitely, there has to be a mechanism which prevents you reaching and exceeding lightspeed; this is where mass dilation comes in (your vessel gets more massive the closer you get to lightspeed, so it would require an infinite amount of energy to actually get there).

[Spiryt]

The premise is that the speed of light is the same for every observer (and that the laws of physics is identical for all speeds, but whatever). From there you can figure out the rest yourself.

Just to clarify, if you travel at the speed of .5 light speed, you'd observe a beam of photons travelling at exactly 1 light speed faster than yourself. So e.g. if it's relative to Earth you're moving at .5 light speed, you'd maybe think that those people down on Earth would see this light beam travel at 1.5 light speed (yours .5 plus the 1 faster than yourself which you're observing the beam travelling), but no they observe it at 1 light speed (0.5 light speed faster than you).

Since speed doesn't change as you'd think, distance and time has to in stead. From a view point of trying to eliminate paradoxes [cause and effect comes to mind], looking at the geometry of the system, etc. you can then figure out how distance and time should change from one speed to another.

That's pretty well put.

Probably hard to put it simpler for our minds. :smallbiggrin:

[Killer Angel]

...and here I was, thinking it was magic...

But yeah, a cookie to Baron. :smallwink:

[Eirala]

As BaronOfHell already mentioned, the speed of light is the largest possible velocity, in any system and for every observer.

The best and vivid explanation i know involves vectors, i hope that still counts als "layman's terms". It's just a little math, i promise.

We start with an x-y-diagram: Picture (http://upload.wikimedia.org/wikipedia/commons/thumb/e/ec/Temporal_velocity_in_relativity.svg/295px-Temporal_velocity_in_relativity.svg.png). The value on the x-axis (below) represents the velocity in time, while the value on the y-axis (left axis) represents the velocity in space.
Now, since the speed of light is the largest possible velocity which counts for all 4 dimensions (3 spacial and one time dimension) the 4 dimensional velocity is always c (the speed of light, represented by the red line).

So, if you do not move in space, you only move in time with the velocity c.
If however you start to move in space, a portion of the temporal velocity becomes spatial velocity, which means you move slower in time (which is represented in the picture, when both parts are somewhat similar). Until at some (theoretical) point you move in space with c, and your temporal velocity is 0. (which you can never actually achieve because your mass becomes infinitely large, but that's another topic)

[Silverrida]

As BaronOfHell already mentioned, the speed of light is the largest possible velocity, in any system and for every observer.

The best and vivid explanation i know involves vectors, i hope that still counts als "layman's terms". It's just a little math, i promise.

We start with an x-y-diagram: Picture (http://upload.wikimedia.org/wikipedia/commons/thumb/e/ec/Temporal_velocity_in_relativity.svg/295px-Temporal_velocity_in_relativity.svg.png). The value on the x-axis (below) represents the velocity in time, while the value on the y-axis (left axis) represents the velocity in space.
Now, since the speed of light is the largest possible velocity which counts for all 4 dimensions (3 spacial and one time dimension) the 4 dimensional velocity is always c (the speed of light, represented by the red line).

So, if you do not move in space, you only move in time with the velocity c.
If however you start to move in space, a portion of the temporal velocity becomes spatial velocity, which means you move slower in time (which is represented in the picture, when both parts are somewhat similar). Until at some (theoretical) point you move in space with c, and your temporal velocity is 0. (which you can never actually achieve because your mass becomes infinitely large, but that's another topic)

This explanation assumes that time works as a spatial dimension. I honestly prefer this explanation, but I feel like the one that Baron gives works better with how Einstein first envisioned Special Relativity.

[Traab]

The premise is that the speed of light is the same for every observer (and that the laws of physics is identical for all speeds, but whatever). From there you can figure out the rest yourself.

Just to clarify, if you travel at the speed of .5 light speed, you'd observe a beam of photons travelling at exactly 1 light speed faster than yourself. So e.g. if it's relative to Earth you're moving at .5 light speed, you'd maybe think that those people down on Earth would see this light beam travel at 1.5 light speed (yours .5 plus the 1 faster than yourself which you're observing the beam travelling), but no they observe it at 1 light speed (0.5 light speed faster than you).

Since speed doesn't change as you'd think, distance and time has to in stead. From a view point of trying to eliminate paradoxes [cause and effect comes to mind], looking at the geometry of the system, etc. you can then figure out how distance and time should change from one speed to another.

I think I catch the gist of what you are saying, but i honestly dont understand how that can work. If I am moving half as fast as light, shouldnt I be visually seeing an effect similar to when I am driving 30 mph down the road and some guy going 60 zooms by? Yes he flies by, but because my speed is half of his, I can see him more clearly, and he passes by me slower than if I was standing on the side of the road. So why wouldnt light do the same thing? (I have no idea what light would even LOOK like if it was going by me slower than usual)

Or is it something really weird like, if light isnt traveling past me at light speed, then it is no longer light and becomes something else? Would I even be able to "see" anything if light is no longer traveling at the same relative rate around me? Holy crap, now I am confusing myself even more.

[Silverrida]

I think I catch the gist of what you are saying, but i honestly dont understand how that can work. If I am moving half as fast as light, shouldnt I be visually seeing an effect similar to when I am driving 30 mph down the road and some guy going 60 zooms by? Yes he flies by, but because my speed is half of his, I can see him more clearly, and he passes by me slower than if I was standing on the side of the road. So why wouldnt light do the same thing? (I have no idea what light would even LOOK like if it was going by me slower than usual)

Or is it something really weird like, if light isnt traveling past me at light speed, then it is no longer light and becomes something else? Would I even be able to "see" anything if light is no longer traveling at the same relative rate around me? Holy crap, now I am confusing myself even more.

The difference is that light's speed limit is set. A vehicle and a human's isn't. Nothing can travel past light, so if the light were to be seen going 1.5x the speed of light, from a relative viewpoint, it would be breaking the laws of physics.

[BaronOfHell]

I think I catch the gist of what you are saying, but i honestly dont understand how that can work.
I'd like to be able to answer you on your follow up questions, but I don't understand the nature of electromagnetic wave propagation well enough to be able to do just that.

In my experience, special relativity does not work so much with the nature of light, as with the consequences of the imposed speed limit that is the speed of light in vacuum.

This I can answer though.

Would I even be able to "see" anything if light is no longer traveling at the same relative rate around me?
Yes, you'd be able to see. Light through a medium, such as water, only travels at a percentage of light speed in vacuum, and you can still see stuff just fine.

In any case, it's not within the scope of special relativity, I think.

[Gray Mage]

I've always found the "light in a train" (I'm not sure if there's an actual name for it) thought experiment usefull for this.

A train moving. Inside a wagon, one person (A) inside the wagon aims a light source towards the ceiling of the wagon, turns it on and times how long it took for the light to reach the ceiling. The light travelled a distance L and took a time t to do it.

Now, a person (B) outside the wagon sees the light travelling as well and does the same, getting a result of a distance D being travelled and that it took a time t'.

The following image illustrates the above.

http://upload.wikimedia.org/wikipedia/commons/a/a5/Time-dilation-002.svg

It's clear that D is greater than L. You'd usually think that the speed in which B saw the light move would be higher than A saw, but the speed of light is a constant that doesn't depend on the observer (that information is obtained by examining Maxwell's equations), so both saw the light moving at the same speed. This means that since B saw the light moving through a higher distance, it also took longer for the light to reach the ceiling.

The important thing to notice is this (faster things moving slower) happens with everything, but it's only noticeable at high (and I mean high) speeds.

Edit:


Yes, you'd be able to see. Light through a medium, such as water, only travels at a percentage of light speed in vacuum, and you can still see stuff just fine.

In any case, it's not within the scope of special relativity, I think.

I believe the gist is more or less the same.

Note that light has a constant speed due to it being an electromagnetic wave, and an electromagnetic wave's speed depends only in which medium it's travelling.

[TSGames]

Put your hands on a hot stove, a minute seems like an hour. Put your hands on a hot woman, an hour seems like a minute.
Stolen from Deep Blue Sea (http://www.imdb.com/title/tt0149261/).
That about covers it.

[Traab]

Ugh, I dont get it, Its like, I can follow most of whats being said, but no matter how hard I try, I just cant wrap my head around the idea that I am seeing light moving just as fast as it always does despite my speed, and even if I do, that this somehow means time is moving faster outside the vessel I am traveling in. My mind is just not able to make this connection. It doesnt make sense to me that moving fast makes time move slower for me than the people I am leaving behind. Hell, I dont even know if thats whats actually happening. All this proves is I will never be a physicist. I could memorize the formulas from now till doomsday, and I would likely never be able to go, "OOOOOH! Now I get it!"

Hmm, maybe this will help. Lets say, just as an example, that I am capable of traveling at .5 light speed around the earth. Ignore all the ways this is impossible, just roll with it. I am circling the world at .5 light speed. What am I physically seeing as I look out the window? Am I able to see anything but a vast blur? (Not counting the constant flicker of night/day switching)

[Gray Mage]

Well, I believe so. I mean, you're going really, really fast. Or do you mean because of the time dilation?
Edit:
At that speed time dilation isn't that big, sort of. It's about 1.15 times difference. It's not like you'd be out for a little while and years or decades have gone by.

[Rawhide]

Preferably in layman's terms. Why does traveling at the speed of light, or close to it, make time move slower for you than for the world around you?

Albert Einstein's Theory of Relativity in words of four letters or less. (http://www.muppetlabs.com/~breadbox/txt/al.html)

[Traab]

Albert Einstein's Theory of Relativity in words of four letters or less. (http://www.muppetlabs.com/~breadbox/txt/al.html)

Heh, I tried to read that, I got lost about halfway through. I just dont think my brain is wired right to understand this. I guess i will just go back to accepting it as the way things are. I dont ask questions too deep into how gravity works, I just accept that it does. I got to the point where he was talking about two rocks falling and depending on what the fixed point was, it varied as to which object hit the ground first. At that point it sounded like it was saying time is based on perception not on actual reality, and then my head started to hurt because I am pretty sure thats not what he meant.

[Eirala]

I just dont think my brain is wired right to understand this. I guess i will just go back to accepting it as the way things are. I dont ask questions too deep into how gravity works, I just accept that it does. I got to the point where he was talking about two rocks falling and depending on what the fixed point was, it varied as to which object hit the ground first. At that point it sounded like it was saying time is based on perception not on actual reality, and then my head started to hurt because I am pretty sure thats not what he meant.

I'm not sure what exactly you're talking about (since i don't know too much about general relativity), but i guess it has to do with the importance of frame of reference.

The thing is, observers in different frames of reference can see different events. For one observer, two events seem simultaneous, and for another one not. But since you can't define "the one true frame of reference" there is no "one truth". Both observers in the example above, one who sees two events simultaneous and one who doesn't, see the reality. The reality just depends on the frame of reference, both perceptions are equally valid.
I hope i didn't confuse you further, and that it was (kind of) ontopic ^.^

[Traab]

I'm not sure what exactly you're talking about (since i don't know too much about general relativity), but i guess it has to do with the importance of frame of reference.

The thing is, observers in different frames of reference can see different events. For one observer, two events seem simultaneous, and for another one not. But since you can't define "the one true frame of reference" there is no "one truth". Both observers in the example above, one who sees two events simultaneous and one who doesn't, see the reality. The reality just depends on the frame of reference, both perceptions are equally valid.
I hope i didn't confuse you further, and that it was (kind of) ontopic ^.^

I can see that happening in the short term, a frame of reference changes how you saw the event take place, what I dont get is how that can translate to what amounts to actual measurable time travel. Lets take the rocks fall example again. Because I stood HERE I saw rock a land first while you stood there and saw rock b land first. Ok, I can accept that. But just because thats what we saw doesnt make it real.

Those two rocks could only have landed in one order, not both, no matter what we saw. Its true that we both observed a different result, but that doesnt mean we were both right. Otherwise this turns into sort of a bastardized version of the schrodeingers cat in a box thought exercise. Its why scientists dont generally try to "eyeball" their tests, they look for precise measurements. So in the rock example, they would solve the dilemma of which rock landed first by repeating the experiment, this time with a pressure sensor mat to record which one actually hit the ground first.

I guess what I am getting at is, again, I dont see how just because due to where I was standing altering which rock I see land first, that means traveling at light speed means everyone will have experienced a buttload more time than I have. I could understand perhaps FEELING like I had experienced less time, but my body should still feel the effects of having existed as long as the outside world. So at best it seems to me that by traveling at close to light speed, I would be like the nazi who picked the wrong grail in indiana jones and the last crusade, and perceive myself as aging rapidly, even though the same actual length of time is passing.

[Salbazier]

Ugh, I dont get it, Its like, I can follow most of whats being said, but no matter how hard I try, I just cant wrap my head around the idea that I am seeing light moving just as fast as it always does despite my speed, and even if I do, that this somehow means time is moving faster outside the vessel I am traveling in. My mind is just not able to make this connection. It doesnt make sense to me that moving fast makes time move slower for me than the people I am leaving behind. Hell, I dont even know if thats whats actually happening. All this proves is I will never be a physicist. I could memorize the formulas from now till doomsday, and I would likely never be able to go, "OOOOOH! Now I get it!"

Hmm, maybe this will help. Lets say, just as an example, that I am capable of traveling at .5 light speed around the earth. Ignore all the ways this is impossible, just roll with it. I am circling the world at .5 light speed. What am I physically seeing as I look out the window? Am I able to see anything but a vast blur? (Not counting the constant flicker of night/day switching)

AFAIK:

Ignoring how medium can affect the speed of light, the speed of light in vacuum is always the maximum speed that it can be. Speed here being relative speed in regard to the observer's frame of reference, be it you or everyone else. No matter how fast how you move the maximum possible speed relative to your frame of reference is C, so you'll always see it as C. Yes, it is not intuitive and hard to wrap around. That just the way it is. Don't give up yet, though. You are hardly the only person who have hard time with it and, no, isn't limited to non-physicist.


As for your example, the blur that you see when you are moving fast are just matter of your eyes cannot see things that are moving fast clearly. Assuming you have the eyes of The Flash/Superman, well, I'm actually a bit sketchy on this, but I remember reading somewhere that you'll end up seeing things have their dimensions distorted somewhat.



Those two rocks could only have landed in one order, not both, no matter what we saw. Its true that we both observed a different result, but that doesnt mean we were both right. Otherwise this turns into sort of a bastardized version of the schrodeingers cat in a box thought exercise. Its why scientists dont generally try to "eyeball" their tests, they look for precise measurements. So in the rock example, they would solve the dilemma of which rock landed first by repeating the experiment, this time with a pressure sensor mat to record which one actually hit the ground first.


To my understanding they are both true, hence 'relativity'. If you several sensors, they would give same measurement if they are have same frame of refence (moving at the same speed). Otherwise, they can give different resluts and each would be equally valid.

[Gray Mage]

Those two rocks could only have landed in one order, not both, no matter what we saw. Its true that we both observed a different result, but that doesnt mean we were both right. Otherwise this turns into sort of a bastardized version of the schrodeingers cat in a box thought exercise. Its why scientists dont generally try to "eyeball" their tests, they look for precise measurements. So in the rock example, they would solve the dilemma of which rock landed first by repeating the experiment, this time with a pressure sensor mat to record which one actually hit the ground first.


Actually, the rocks always land on one particular order that is the same for both. The thing is that you may see a diferent order then what happened, but if you take into account the time that the light reflected from each rock to reach you, you'll get the correct order, no matter where you're at.



I guess what I am getting at is, again, I dont see how just because due to where I was standing altering which rock I see land first, that means traveling at light speed means everyone will have experienced a buttload more time than I have. I could understand perhaps FEELING like I had experienced less time, but my body should still feel the effects of having existed as long as the outside world. So at best it seems to me that by traveling at close to light speed, I would be like the nazi who picked the wrong grail in indiana jones and the last crusade, and perceive myself as aging rapidly, even though the same actual length of time is passing.

Well, it'd be the opposite, actually. The other'd be the ones to age "faster". But the thing is, it's not the same lenght at all, that's kind of the point. There isn't some sort of absolute timeframe, only relative ones.

[factotum]

Hmm, maybe this will help. Lets say, just as an example, that I am capable of traveling at .5 light speed around the earth. Ignore all the ways this is impossible, just roll with it. I am circling the world at .5 light speed. What am I physically seeing as I look out the window? Am I able to see anything but a vast blur? (Not counting the constant flicker of night/day switching)

If you were flying in a straight line at 0.5c, all the stars in front of you would have their light shifted up toward the blue end of the spectrum, while the ones behind would be headed toward the red end. If you were going fast enough (and I don't know if 0.5c would be sufficient for this to happen) the light coming in from the front would all be shifted to ultraviolet frequences, so the stars would disappear; the ones behind would disappear as their light got shifted into the infra-red. You'd end up travelling down a "tunnel" of stars, which I reckon would be a way cool effect!

[SanguisAevum]

Another common example of relativity....

Take two people
Put one on a bus with a ball.
Put the other on the side of the road.
Have the bus drive by the person at the side of the road.
Whilst the bus passes, the person sat on the bus throws the ball up and catches it as it comes back down.

Relative to the person on the bus, the ball goes up and down in space, as it travels only vertically.
Relative to the person on the side of the road, the ball describes an arc through space, as it travels both vertically and horizontally.

[BaronOfHell]

I think I catch the gist of what you are saying, but i honestly dont understand how that can work.

I was pondering this question some more, and I can give a more philosophical answer. It may not be how the world works, but it can give a more intuitive idea of why the premise of special relativity makes sense.


The premise is that the speed of light is the same for every observer (and that the laws of physics is identical for all speeds, but whatever).



If I am moving half as fast as light, shouldnt I be visually seeing an effect similar to when I am driving 30 mph down the road and some guy going 60 zooms by? Yes he flies by, but because my speed is half of his, I can see him more clearly, and he passes by me slower than if I was standing on the side of the road. So why wouldnt light do the same thing?

So talking out of my butt here.. the entire universe is a bunch of reactions happening at different rates. A reaction is basically energy transfer between two particles in an unfathomable large amount of particles.

What determines the rate of these reactions? The macroscopic clue an reaction had occurred is some kind of consequence, such as a color change. The amount of particles which needs to interact before this color changes happens is to a large degree what determines the speed of this reaction.
There are more stuff, like how easy these particles are to move through space, the energy at which they're held to other particles, etc., but while it's still in the scope of special relativity, it does not concern your question currently.

So interaction is basically a transfer of information, and how does information transfer? Through radiation, i.e. light and all other waves on the electromagnetic spectrum. In other words, light is the carrier of information and light speed is the speed at which information travels!.

In the car example, the car goes fast as the friction between the wheels and the car itself makes it go forward. The particles on the ground and in the tire interacts and this interaction happens at the speed of light. Since the car is also moving forward, relative to the ground it moves on, the light beam which has to travel between the ground and the tire (a very small distance), has to also travel a very very very ... very small distance in the cars direction, because the car is moving.

So what does this matter? Since due to the geometry of the system, the information carrier, i.e. the light beam, has to travel a longer distance than when the car is at rest, the reaction itself slows down.

The guy outside the car "observes" this, but it's so small a difference, because the car moves so slowly compared to the speed of light, he can't tell, hence the marks around "observe".
So why do the guy in the car not observe this? Well I'll come back to this, but now we'll change the car with a beam of light to make it more clearly.


if you travel at the speed of .5 light speed, you'd observe a beam of photons travelling at exactly 1 light speed faster than yourself. So e.g. if it's relative to Earth you're moving at .5 light speed, you'd maybe think that those people down on Earth would see this light beam travel at 1.5 light speed (yours .5 plus the 1 faster than yourself which you're observing the beam travelling), but no they observe it at 1 light speed (0.5 light speed faster than you).

Back to the example I gave and the difference between a beam of light and a car. Recalling the beam of light is the carrier of information between components in reactions, a person is on Earth and another person is moving at .5 light speed relative to Earth.
The person on Earth observes a light beam passing the guy moving at .5 light speed, at exactly light speed, .5 light speed faster than the person moving.
However the person moving is observing the beam at 1 light speed faster than himself. What is going on?
Because light is the carrier of information, and thereby determines the speed of reaction, when on person is moving at .5 light speed, all his inner and outer particles is moving at .5 light speed. But they're still at rest relative to one another. Therefore, from your perspective, defined through the particle reactions taking place inside of you, light behaves as it always do, moving at light speed, your reactions are happening as the usual speed, you don't feel "slow", because every mean you've of observing yourself (particles reacting within you) is at rest relative to one another.
On the other hand, and now this is compared to the car example, from the perspective of the person on Earth, all your particles are moving, and like the tires relative to the ground when the car was moving, the information has a longer distance. The guy moving at 0.5 light speed doesn't observe this, because all information is travel is slowed down equally, thereby everything seems normal, all reactions seems to go at the usual speed. From the perspective of the person on Earth, all the reactions are going slower on the guy moving.

The net result is that the guy moving experiences less time, which is a physical phenomena, not a mental one like:

Put your hands on a hot stove, a minute seems like an hour. Put your hands on a hot woman, an hour seems like a minute.
Similarly, as less time is experienced, so is a smaller distance, hence the observed world shrinks for the guy moving relative to the Earth and everything adds up.

So how does this relate to the car example? The car moving at 60 mph, all the particles in the drivers body, in the car, etc. is slowed down relative to the ground where the other guy is standing, because light, as the carrier of information, has to travel longer from the perspective of the guy on the ground. From the perspective of the guy in the car, everything is normal at his speed (his frame of reference), since everything is slowed down equally, he can't tell the information is travelling slower, because the entire world of his is slower. He can only tell by looking at a system moving at a different speed. The same goes for the guy on the ground. Only because the speed is so low compared to the speed of light, there's no macroscopic effect a human can observe, but the guy in the car does age a tiny tiny bit slower, i.e. he's in a lousy time machine moving forward in time a little faster than the guy on the ground in his time machine. (We're all in a time machine moving forward through time in this sense).

Sorry about this getting so long, I might try later to shorten it, or write it differently. In any case, just to answer a typical following question: How come the guy moving at .5 light speed is the one experience the effects of relativity, when the guy on the Earth is also moving .5 light speed, compared to the first guy? As far as I know, it has to due with who's accelerated into a different speed, but I believe acceleration to a speed, and not what happens at a given speed, is outside of the scope of special relativity and has more to do with general relativity. Though I do believe that the guy moving at .5 light speed relative to the Earth sees smaller distances, so to him the Earth is not moving .5 light speed relative to him, etc.

Edit: TL;DR version:
Even when we're at speed relative to the Earth, we can't observe a light beam ever moving faster than light speed, because at our own speed, as a biological system part of the universe like any other particle, our inner processes are slowed down equally.

[The Rose Dragon]

By the way, it sort of helps if you stop thinking of time as the passage of seconds (which is a constant that relies on the speed of light in vacuum) and start thinking in terms of reaction rates (which are, at least in chemistry, so fickle that almost anything can alter them).

[Feytalist]

If you were flying in a straight line at 0.5c, all the stars in front of you would have their light shifted up toward the blue end of the spectrum, while the ones behind would be headed toward the red end. If you were going fast enough (and I don't know if 0.5c would be sufficient for this to happen) the light coming in from the front would all be shifted to ultraviolet frequences, so the stars would disappear; the ones behind would disappear as their light got shifted into the infra-red. You'd end up travelling down a "tunnel" of stars, which I reckon would be a way cool effect!

I sorta-kinda understand the concept of time dilation/expansion itself, but red-shifting and blue-shifting has always boggled my mind. It seems like such a weird but wonderful concept. Like you say, I'd love to see it in action just for the view.

[Gray Mage]

I sorta-kinda understand the concept of time dilation/expansion itself, but red-shifting and blue-shifting has always boggled my mind. It seems like such a weird but wonderful concept. Like you say, I'd love to see it in action just for the view.

Well, it's the Doppler effect in action. Should be a sight to see, though.

Edit: This (http://apod.nasa.gov/apod/ap111018.html) video might help show some of the things that happen when you travel near the speed of light.

[Gravitron5000]

MIT created a game (3D, 1st person) in which you are able to slow down the speed of light by picking up orbs. It is a neat tool to help you visualize relativistic effects.

http://gamelab.mit.edu/games/a-slower-speed-of-light/

[Traab]

Well, it's the Doppler effect in action. Should be a sight to see, though.

Edit: This (http://apod.nasa.gov/apod/ap111018.html) video might help show some of the things that happen when you travel near the speed of light.

The doppler effect is what I was thinking of when I talked about "seeing" light differently way back in my posts. Now, the part that confuses me is many fold. But here is the big one for me. If I will always perceive light as moving at light speed relative to me no matter how fast I am going, why would the doppler effect even happen? Woudlnt that, by definition, mean that light is not moving around me at the same speed relative to me?

[Gray Mage]

The doppler effect is what I was thinking of when I talked about "seeing" light differently way back in my posts. Now, the part that confuses me is many fold. But here is the big one for me. If I will always perceive light as moving at light speed relative to me no matter how fast I am going, why would the doppler effect even happen? Woudlnt that, by definition, mean that light is not moving around me at the same speed relative to me?

The key word here is perceive. The doppler effect changes the apparent frequency of a wave, not its speed or the actual frequency.

Edit: Although note that redshift/blue shift would still happen without the theory of relativity, although the equation would be a little different.

Edit 2: Also, the Doppler effect doesn't change the apparent speed of a wave, but it's frequency and wave number.