Planck time at the speed of light

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SUMMARY

The discussion centers on the misconceptions surrounding Planck time and the behavior of massless particles, specifically photons, at the speed of light. It is established that objects with mass cannot reach the speed of light, and thus, the concept of time stopping for them is fundamentally flawed. The smallest unit of time, Planck time, does not imply that massless particles experience time in the same way as massive objects. The thread concludes that the assumptions made in the original question are incorrect and highlights the need for clarity on these concepts.

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  • Understanding of special relativity and its implications on massless particles
  • Familiarity with Planck time and Planck length concepts
  • Knowledge of reference frames in physics
  • Basic grasp of dimensional analysis in theoretical physics
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Adgorn
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I know that if an object moves at the speed of light, from its persepctive time will stop to a halt. However the smallest unit of time should be the plank time. So my question is, will the object (say a photon) experience throughout its life a single still "frame", or will it experience 5.39121e-44 seconds?
 
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I had the same thought some time back and I was reminded here that Plank time / Plank length are numbers that arise from dimensional analysis, and they do not necessarily have specific physical significance.

Unless I misunderstood what I read at the time - there is no theory that says the smallest unit of time is the Plank time or that the smallest distance is the Plank length.
 
Adgorn said:
I know that if an object moves at the speed of light, from its persepctive time will stop to a halt.

No, it's not true at all, because:
1. objects with mass cannot move at the speed of light
2. only massless objects can move at the speed of light and for that objects there is no "perspective", there is no reference frame connected with them (that would violate the fact that light moves at c in all FORs) - and with that, you can't say that time will stop for them. Probably you've read that in some pop-sci book, you shoud totally forget about it :)
So, your question is based on totally wrong assumptions, so there is no answer to it.
 
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Adgorn said:
if an object moves at the speed of light, from its persepctive time will stop to a halt.
However the smallest unit of time should be the plank time.
Both of those statements are wrong, although these misunderstandings are so pervasive that we have FAQ and Insights articles explaining why they're wrong.
https://www.physicsforums.com/threads/rest-frame-of-a-photon.511170/
https://www.physicsforums.com/insights/hand-wavy-discussion-planck-length/ (although this discusses the Planck length, similar considerations apply to the Planck time)
This thread is closed because it is completely based on false premises.
 
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