Another Speed Of Light Travel Scenario

In summary, the conversation discusses the idea of traveling at the speed of light and how it would affect one's perception of time and space. The participants also touch upon the concept of relativity and the limitations of trying to imagine what it would be like to travel at the speed of light. The conclusion is that such hypothetical scenarios do not have definitive answers and can lead to paradoxes.
  • #1
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If i were traveling on a train going at the speed of light and looking at the window on my right side, photons emitted by objects on the right side of the train would still collide with my retina, causing me to see something, probably a blur or continuous flash because I'm traveling so fast. A more interesting scenario is when the train is traveling in space, with two very big objects on the right side very far away. Here's a picture:
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[COLOR="White"]..........[/COLOR]O
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[COLOR="DarkGreen"]( )
(x)
( )[/COLOR]
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[COLOR="White"]..........[/COLOR]O
Where the train is shown in green, x is were i am, and the Os are the two very large objects. Suppose the Objects have the same size, are as far away from each other as they are from the rails of the train (this distance being about a light year) and that they are big enough so that to me, sitting in the train, they look like two small moons. The train starts in the middle of the tracks so that in the beginning i see these two objects as being of the same size. If the train starts to move up at the speed of light, with me looking over my shoulder at the two objects, as mentioned above the photons reaching me from these objects would still reach my eyes, though rather than two objects i might just see the line created by the blur of these objects.
Finally, suppose i had suffered some brain damage in the optical regions of my brain such that i was only able to see for a very short interval of time T every S seconds. Suppose T is very, very small, and S = 5. Then, every 5 seconds i would have a clearer view of the two objects, in fact, we may say that there is a sufficiently small T such that, every S seconds i would be able to see the two objects very clearly. Under this scenario, even though i am traveling at the speed of light, i would see one of the objects get bigger and the other get smaller, apparently going against the stipulation that time comes to a halt at when you reach the speed of light. Any thoughts on this?

EDIT: Even if i hadn't the brain damage, assuming the two objects are the only visible ones on the side of the train, would they be blurred at all?
 
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  • #2
-Job- said:
If i were traveling on a train going at the speed of light and looking at the window on my right side,

Whoa! You can't be on a train traveling at the speed of light - not if you are applying relativity.

If you arrive at a paradox, it is because your initial assumptions (that you were on a train traveling at an impossible velocity) were bad.
 
  • #3
Oh, come on, how can i argue against that? Isn't there something about the validity of irrefutable theories? So much work making the picture look pretty for nothing. :smile:
 
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  • #4
-Job- said:
Oh, come on, how can i argue against that? Isn't there something about the validity of irrefutable theories? So much work making the picture look pretty for nothing. :smile:
If you are going to "refute" relativity, it is going to be by experiment, because the theory is mathematically self-consistent. What you are doing is akin to the old mathematical "paradox" that shows 1=2, i.e.

1*0 = 2*0

divide both sides by zero and you get

1=2

Sorry, but you can't divide by zero, nor can a material body travel at the speed of light if one is using the special theory of relativity.

This is well-known, see for instance the sci.physics.faq
http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/headlights.html" [Broken]

Sadly this question and all others about experiences at the speed of light do not have a definitive answer. You cannot go at the speed of light so the question is hypothetical. Hypothetical questions do not have definitive answers. Only massless particles such as photons can go at the speed of light. As a massive object approaches the speed of light the amount of energy needed to accelerate it further increases so that an infinite amount would be needed to reach the speed of light.

Sometimes people persist: What would the world look like in the reference frame of a photon? What does a photon experience? Does space contract to two dimensions at the speed of light? Does time stop for a photon?. . . It is really not possible to make sense of such questions and any attempt to do so is bound to lead to paradoxes. There are no inertial reference frames in which the photon is at rest so it is hopeless to try to imagine what it would be like in one. Photons do not have experiences. There is no sense in saying that time stops when you go at the speed of light. This is not a failing of the theory of relativity. There are no inconsistencies revealed by these questions. They just don't make sense.
 
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  • #5
I'm not trying to go against GR, just the traditional word-of-mouth idea that if you were traveling at the speed of light time would stand still, which actually comits the same error (how is the person traveling at the speed of light?). I'm making the same erroneous assumptions because I'm starting from the given scenario.
I think a better question is what does it mean that time comes to a halt for a given photon and what are the implications of this?
 
  • #6
-Job- said:
I'm not trying to go against GR, just the traditional word-of-mouth idea that if you were traveling at the speed of light time would stand still, which actually comits the same error (how is the person traveling at the speed of light?). I'm making the same erroneous assumptions because I'm starting from the given scenario.
I think a better question is what does it mean that time comes to a halt for a given photon and what are the implications of this?
Photons don't have valid rest frames, because one of the postulates of relativity is that the laws of physics should work the same way in all inertial frames, so if light moves at c in some frames, it must move at c in all valid frames. So, it doesn't really make sense to talk about what things look like from a photon's point of view. You can take the limit of what an object would see as it approached a velocity of c relative to most of the rest of the universe--say, relative to the rest frame of the galaxy--and in this limit it is true that clocks in the galaxy approach being stopped, and the length of the galaxy along the direction the object is traveling approaches zero, so the time it sees to cross the galaxy approaches zero too. So you could sort of get the idea from this that a photon would see all clocks frozen, and that it would see lengths compressed to zero along the direction it's traveling so its entire path through spacetime would be a point which takes zero time to cross. Unfortunately a lot of things don't have a well-defined limit as you approach c, like the velocity of other objects moving at c--depending on how you take the limit you could either conclude they're still moving at c or that they're at rest. So there's really no way to give any sort of answer to the question of what one photon would look like to another photon.
 

1. What is a "Another Speed Of Light Travel Scenario"?

A "Another Speed Of Light Travel Scenario" is a hypothetical concept that explores the possibility of traveling faster than the speed of light, which is currently considered to be the maximum speed limit in the universe.

2. Is it possible to travel faster than the speed of light?

According to our current understanding of physics and the laws of the universe, it is not possible to travel faster than the speed of light. The theory of relativity, proposed by Albert Einstein, states that the speed of light is a fundamental constant and cannot be exceeded.

3. How does the theory of relativity affect the concept of "Another Speed Of Light Travel Scenario"?

The theory of relativity is the basis for our understanding of the universe and the laws of physics. It states that as an object approaches the speed of light, its mass increases and it requires infinite energy to reach the speed of light. Therefore, the theory of relativity makes it highly unlikely that "Another Speed Of Light Travel Scenario" is possible.

4. What are some proposed theories for "Another Speed Of Light Travel Scenario"?

Some theoretical concepts for "Another Speed Of Light Travel Scenario" include wormholes, which are hypothetical tunnels through space-time that could potentially allow for faster-than-light travel, and the Alcubierre drive, which proposes the use of negative energy to warp space-time and travel at superluminal speeds.

5. How does the study of "Another Speed Of Light Travel Scenario" impact our understanding of the universe?

Exploring the concept of "Another Speed Of Light Travel Scenario" allows scientists to push the boundaries of our understanding of the universe and challenge our current theories and beliefs. It also opens up new possibilities and potential advancements in technology that could one day lead to breakthroughs in space travel and exploration.

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