Does Light Experience Time Differently Than We Do?

  • Context: Graduate 
  • Thread starter Thread starter zeromodz
  • Start date Start date
  • Tags Tags
    Light
Click For Summary

Discussion Overview

The discussion centers on the nature of light and its relationship with time, particularly whether light experiences time differently than observers do. Participants explore concepts related to the aging of light, the perspective of photons, and the implications of relativistic effects on time perception.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants propose that if light is timeless, then everything we see is merely the light that has traveled for billions of years.
  • Others argue against the notion of light being timeless, suggesting that this perspective misinterprets the sequence of events as having absolute meaning.
  • One participant asserts that light does not age and that its proper time is constant, leading to the conclusion that from the perspective of light, emission and absorption occur simultaneously.
  • Another viewpoint suggests that discussing the age of light is problematic, as it depends on one's understanding of time and space.
  • A later reply explains that from a photon's reference frame, the time between emission and absorption is zero, while from an observer's frame, the durations differ significantly.

Areas of Agreement / Disagreement

Participants do not reach a consensus, with multiple competing views on whether light is timeless and how it relates to the concept of time. The discussion remains unresolved, highlighting differing interpretations of time and light.

Contextual Notes

Limitations include varying definitions of time, the dependence on reference frames, and unresolved implications of relativistic effects on the perception of time and light.

zeromodz
Messages
244
Reaction score
0
If light is timeless (photons), then doesn't that mean that everything we see is just 13.7 billion year old light?
 
Science news on Phys.org
Light is not "timeless". Your mistaking a perspective dependent sense of a sequence of events as something that has absolute meaning independent of your perspective.
 
zeromodz said:
If light is timeless (photons), then doesn't that mean that everything we see is just 13.7 billion year old light?

Where did you get the idea that photons were timeless? And your conclusion indicates that's not what you believe.
 
Light doesn't age. It's proper time is always a constant, because it moves along null-geodesics.

That means from perspective of light, it's emission and absorption happen at the same time. It doesn't mean all light is the age of the universe. That right there is a strange leap of logic.
 
K^2 said:
Light doesn't age. It's proper time is always a constant, because it moves along null-geodesics.

That means from perspective of light, it's emission and absorption happen at the same time. It doesn't mean all light is the age of the universe. That right there is a strange leap of logic.
Right: it would be closer to reality to say that all light has an age of 0.
 
It depends entirely on what you regard as time.
Space is time and time is space.

From one person's point of view a parsec is a parsec. From someone else's it could be a couple of days.

You can't talk about the age of light any more than you can talk about it's length.
 
Here's an easy way to understand it: from the photon's reference frame, the time between emission and absorption is 0, but from our frame of reference, this is clearly not the case. Light emitted 13 billion years ago (cosmic background microwaves) and light emitted from your computer screen about a nanosecond ago (From memory/really rough estimation, It seems that it should take about one nanosecond for the light coming from your computer to reach your eye), from the perspective of the photon, exists for the same duration, namely zero duration. Now, from our reference frame, they take vastly different amounts of time. Now, if you moved with the photon at a speed really close to its speed, the closer both 13 billion years and one nanosecond would be to each other, and to zero. Your speed in space affects your speed in time.
 

Similar threads

  • · Replies 15 ·
Replies
15
Views
3K
  • · Replies 24 ·
Replies
24
Views
3K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 18 ·
Replies
18
Views
4K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 5 ·
Replies
5
Views
6K
  • · Replies 40 ·
2
Replies
40
Views
5K