Thought experiment on the nature of light

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SUMMARY

This discussion centers on a thought experiment regarding the nature of light, specifically the behavior of light beams in relation to observers moving at different velocities. The experiment involves three participants: John, who remains stationary, and another individual moving at 60 mph away from a light beam emitted by Jane, who is one light minute away. Key conclusions include that the moving observer will detect the light beam slightly after 1:01 pm and will have traveled slightly more than one mile by that time. Additionally, it is established that photons do not decay over time, which impacts the perceived decay of light between different observers.

PREREQUISITES
  • Understanding of special relativity principles
  • Familiarity with the concept of light speed (c)
  • Basic knowledge of time dilation effects
  • Awareness of photon behavior and properties
NEXT STEPS
  • Research the implications of special relativity on light perception
  • Study the concept of simultaneity in different frames of reference
  • Explore the properties of photons and their behavior in various conditions
  • Investigate the effects of velocity on time perception and measurement
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Physicists, students of physics, and anyone interested in the fundamental principles of light and relativity will benefit from this discussion.

rede96
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There have been a number of very interesting posts lately around the nature of light. So I devised a simple thought experiment to try and understand it a bit more.

Say John and I are next to each other in rocket ships, at rest wrt to Jane, who is 1 light minute away in her rocket ship. All our clocks are synchronised.

We have an experiment planned that at exactly 1pm, Jane will send a light beam towards John and I.

At the same time, I will set off in the opposite direction to the light beam, moving away from it as it were.

My velocity is only slow wrt to John and Jane at 60 mph, therefore I will ignore the very small effects of time dilation between John, Jane and I.

The clock strikes 1pm and Jane fires the light beam and I set off.

I detect the light beam, stop my rocket and head back towards John in order to compare results.

What would I find for the following?

a) John would detect the light beam at exactly 1:01pm. Would I have detected the light beam also at 1:01pm or very slightly afterwards?

b) Would I have traveled exactly 1 mile away from John by the time I detected the light beam?

c) If there was a way to very accurately detect the decay in the photons from the light beam (Assuming the photons do decay with time) would John and I have detected the same amount of decay or would I have detected slightly more decay that John?

Hope that makes sense!
 
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You will detect the light beam slightly after 1:01pm and you will have traveled slightly more than 1 mile when you detect it.

Photons don't decay.
 
ghwellsjr said:
You will detect the light beam slightly after 1:01pm and you will have traveled slightly more than 1 mile when you detect it.

That was pretty much as expected, thanks. Just wanted to make sure :)

ghwellsjr said:
Photons don't decay.

Shame, this was the bit I was really interested in. If photon's did decay, or there were some other matter with zero rest mass that did, I wondered if the measured decay would be the same for both John and me.

I.e. because traveling at c would mean the photon ( or similar ) would not have 'aged' relative to me or John.

Which then made me wonder than if anything that can travel at c would not decay relative to sub-light frames of reference?
 

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