# Those Crazy Photons?

**URL:** <https://boards.straightdope.com/t/those-crazy-photons/83266>\
**Category:** Factual Questions\
**Created:** [September 23, 2001, 12:21am UTC](https://boards.straightdope.com/t/those-crazy-photons/83266 "2001-09-23T00:21:11Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![erislover](https://avatars.discourse-cdn.com/v4/letter/e/71e660/32.png) [@erislover](https://boards.straightdope.com/u/erislover)\
**Post date:** [September 23, 2001, 12:21am UTC](https://boards.straightdope.com/t/those-crazy-photons/83266/1 "2001-09-23T00:21:11Z")

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Do photons “experience” time, or does everything happen simultaneously for a photon?

I swear I read about a physicist who commented that all light in the universe could be the result of a single photon bouncing back and forth throughout time, and drew a 2-D “world sheet” to demonstrate the point.

Was I dreaming?

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**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\
**Post date:** [September 23, 2001, 2:46am UTC](https://boards.straightdope.com/t/those-crazy-photons/83266/2 "2001-09-23T02:46:51Z")

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> [@](#):
>
> "Do photons “experience” time, or does everything happen simultaneously for a photon?

Photons do not experience time. A photon cannot have a frame of reference because light must travel at c wrt to all frames of reference and light cannot travel at c with respect to light. And therefore no photon can be emitted unless it’s absorbed. In more conventional terms the time dilation of a photon is infinite. 1 / sqrt (1 - c[sup]2[/sup] / c[sup]2[/sup]) = infinity.

All subatomic particles’ Feynman diagrams (a worldline of sorts) are symmetric wrt to time, and therefore _all_ subatomic particles could be the result of one of those types bouncing back and forth throughout time

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**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\
**Post date:** [September 23, 2001, 5:00am UTC](https://boards.straightdope.com/t/those-crazy-photons/83266/3 "2001-09-23T05:00:58Z")

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> [@](#):
>
> \*Originally posted by erislover \*  
> **I swear I read about a physicist who commented that all light in the universe could be the result of a single photon bouncing back and forth throughout time, and drew a 2-D “world sheet” to demonstrate the point.**

I don’t remember hearing that, but it brings to mind an idea that Wheeler briefly held: that all the electrons and positrons in the universe might be a single particle going back and forth in time. That would explain why all electrons have the same rest mass and charge, anyway.

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [September 23, 2001, 5:41am UTC](https://boards.straightdope.com/t/those-crazy-photons/83266/4 "2001-09-23T05:41:25Z")

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It’s an interesting notion, that bouncing through time, but it’s disprovable. You can use a couple of gamma rays to produce an electron-positron pair, observe the two particles, and then let them re-annihilate into gammas. There you have it, an electron definitely disconnected from all other electrons.