Question about the speed of light and relativity

In summary, the discussion revolves around the concept of time dilation and its implications on the eternal existence of light. It is argued that if light does not experience time dilation, then it could potentially exist forever as long as it does not interact with anything. However, the idea of eternity is questioned and it is suggested that only in a classical Newtonian sense can something be considered truly eternal. The conversation also touches on the concept of consciousness and the potential implications of time dilation on the aging process.
  • #1
Carnivroar
128
1
If light always travels at the speed of light,

and at the speed of light, time stops --

does this mean that light is eternal?

In other words, if you were a particle of light, you would exist forever?
 
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  • #2
Well, if light doesn't follow the rules of having to travel below the speed of light, then it's likely to say that they don't experience time dilation. If they did, we would literally see every photon everywhere at once.
 
  • #3
Carnivroar said:
If light always travels at the speed of light,

and at the speed of light, time stops --

does this mean that light is eternal?

In other words, if you were a particle of light, you would exist forever?
Yes, as long as it didn't interact with anything. The cosmic microwave background consists of photons from the big bang (after about 300,000 years, when the universe cooled down enough so the photons would stop interacting). The long wavelength results from the expansion of the universe since then.
 
  • #4
Carnivroar said:
If light always travels at the speed of light,

and at the speed of light, time stops --

does this mean that light is eternal?

In other words, if you were a particle of light, you would exist forever?

What do you mean by exist forever? Time dilation of relativity means time measurement is dilated i.e. what a man travels near the speed of light would be extremely long via the measurement of a resting man. But there's no point in eternal, eternal is quite like a classical sense. If you can live 90 years, whatever the speed you are travelling, you would live 90 years. Only in classical Newton's "time", there would be "eternality".
 
  • #5
ZealScience said:
What do you mean by exist forever? Time dilation of relativity means time measurement is dilated i.e. what a man travels near the speed of light would be extremely long via the measurement of a resting man. But there's no point in eternal, eternal is quite like a classical sense. If you can live 90 years, whatever the speed you are travelling, you would live 90 years. Only in classical Newton's "time", there would be "eternality".

I see what you mean. I'm having trouble swallowing the idea of eternity myself.

Let me see if I can rephrase this. Suppose light had consciousness and it was moving at the speed of light (where time supposedly stops?), would it then experience existence forever as long as it's speed remained undisturbed? It would never "age"?

Anyways looks like I found a thread on precisely this, https://www.physicsforums.com/showthread.php?t=235132, I'm going to read it now.
 
Last edited:

1. What is the speed of light and why is it important?

The speed of light is a fundamental physical constant measuring the speed at which light travels in a vacuum. It is represented by the letter "c" and has a value of approximately 299,792,458 meters per second. It is important because it is the fastest possible speed at which energy, matter, and information can travel, and it plays a crucial role in many aspects of modern physics, including relativity.

2. How does the speed of light relate to Einstein's theory of relativity?

Einstein's theory of relativity, specifically the special theory of relativity, states that the laws of physics are the same for all observers in uniform motion. This theory is based on the constant speed of light in a vacuum, which is the same for all observers regardless of their relative motion. This means that the speed of light is a fundamental and unchanging aspect of the universe and is necessary for understanding the relationship between space and time.

3. Is the speed of light the fastest possible speed in the universe?

Yes, according to our current understanding of physics, the speed of light is the fastest possible speed in the universe. This is because as an object approaches the speed of light, its mass increases infinitely and requires an infinite amount of energy to accelerate further. This makes it impossible for any object with mass to reach or exceed the speed of light.

4. What is the significance of the speed of light in everyday life?

The speed of light is not significant in our everyday life as we do not usually encounter situations where we need to consider or measure it. However, our understanding of the speed of light and its role in relativity has greatly influenced technologies such as GPS, satellite communication, and nuclear energy, which affect our daily lives.

5. Can anything travel faster than the speed of light?

Based on our current understanding of physics, it is not possible for anything to travel faster than the speed of light in a vacuum. However, some theories, such as wormholes and the concept of warp drive, suggest that it may be possible to exceed the speed of light by warping or bending space-time. These ideas are still purely theoretical and have not been proven or observed in our physical reality.

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