How long does a ray of light travel for based on ITS time scale

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Discussion Overview

The discussion revolves around the concept of time experienced by a ray of light traveling from the sun to the Earth, particularly in the context of relativity. Participants explore the implications of traveling at the speed of light and the nature of time in different reference frames.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant expresses confusion about how long a ray of light takes to travel from the sun to the Earth, questioning the experience of time if one could travel with the light.
  • Another participant explains that time passes more slowly in a moving frame and asserts that time does not pass at all for a light beam, suggesting that if one could travel with it, they would experience no time passing.
  • Some participants argue that it is impossible to travel along a beam of light due to the requirement of infinite energy to reach the speed of light.
  • A participant mentions that the question may be considered meaningless, emphasizing that the correct interpretation is that the question does not make sense in the context of relativity.
  • Another participant counters that while the question may seem meaningless, it is true that all events along the light beam are simultaneous in any reference frame, suggesting that "time stands still along the light beam." However, they acknowledge that this perspective may be overly simplistic.
  • There is a disagreement regarding the simultaneity of events along the light beam, with one participant asserting that events are not simultaneous in any inertial frame.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of the question posed. There are competing views regarding the meaning of the question and the implications of simultaneity along the light beam.

Contextual Notes

Some discussions highlight the limitations of the question based on assumptions about traveling at the speed of light and the nature of time in different reference frames. There is also mention of the need for clarity regarding the consciousness of photons, which remains unresolved.

swraman
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Hi,

Ive been readin about relativity, I am a little confused.

The faster speed an object has, the faster time passes on the object.

So how long does say a ray of light take to get from the sun to the earth? It is ~8.5 of our minutes, but say I were on the ray of light; traveling with it as soon as it left the sun towards . How long would my trip to the Earth be?

thanks
 
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Actually, time passes more slowly in a moving frame by a factor of Gamma=1/sqrt(1-v^2/c^2). Since a light beam travels at c, time does not pass at all. You can't "travel along with the light beam" , because you have mass and it would take an infinite amount of energy to accelerate you to the speed of light. However, if you could travel along with the light beam, you would experience no time passing at all. In other words, the light beam leaving the sun and the light beam arriving at the Earth are simultaneous events.
 
You can't travel along a beam of light; it goes with the speed of light.
 
We've been getting this question twice a week lately. Please check out some of the other threads, e.g. this one (which is still only half-way down the first page). The correct answer isn't "zero" as phyzguy is suggesting. It's that the question doesn't make sense. I explained the reasons in several of the other threads.
 
While you can say that it is in some sense a meaningless question, since you can't travel along the light beam (as I said in my post), it is clearly a true statement that all events along the light beam are simultaneous in any reference frame.

So in the simple context in which the questions was asked, I think the correct answer to the OP's question is that "Time stands still along the light beam". I've read some of the other posts on this topic, and IMHO they are simply too pedantic.
 
phyzguy said:
While you can say that it is in some sense a meaningless question, since you can't travel along the light beam (as I said in my post), it is clearly a true statement that all events along the light beam are simultaneous in any reference frame.
Actually they're not simultaneous in any inertial frame.

phyzguy said:
I've read some of the other posts on this topic, and IMHO they are simply too pedantic.
Some of them might be (in particular the ones that point out that photons aren't conscious), but I don't think mine are.
 

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