# Photon Speed **URL:** \ **Category:** Factual Questions\ **Created:** [September 10, 2001, 11:07pm UTC](https://boards.straightdope.com/t/photon-speed/80767 "2001-09-10T23:07:26Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![BuddhaDog](https://avatars.discourse-cdn.com/v4/letter/b/ea5d25/32.png) [@BuddhaDog](https://boards.straightdope.com/u/BuddhaDog)\ **Post date:** [September 10, 2001, 11:07pm UTC](https://boards.straightdope.com/t/photon-speed/80767/1 "2001-09-10T23:07:26Z")
How do emitted photons instantaneously travel at the speed of light since they were not accelerated? At one instant there is no photon, and at the next instant, it miraculously is already travelling at the speed of light. ---
**Author:** ![xash](https://avatars.discourse-cdn.com/v4/letter/x/c6cbf5/32.png) [@xash](https://boards.straightdope.com/u/xash)\ **Post date:** [September 11, 2001, 12:28am UTC](https://boards.straightdope.com/t/photon-speed/80767/2 "2001-09-11T00:28:20Z")
something like kicking a football…it starts at 0 and goes into the air real fast…only kick it real hard 😃 interesting question…hope someone will shed some light on this soon…i’d like to _see_ an answer… ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [September 11, 2001, 12:48am UTC](https://boards.straightdope.com/t/photon-speed/80767/3 "2001-09-11T00:48:10Z")
I think it just a property of a photon. When the photon pops into existance it is at the SOL. ---
**Author:** ![bouv](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@bouv](https://boards.straightdope.com/u/bouv)\ **Post date:** [September 11, 2001, 1:04am UTC](https://boards.straightdope.com/t/photon-speed/80767/4 "2001-09-11T01:04:26Z")
It might have something to do with the fact that is has no mass, and therefore doesnot need to be accelerated. (remember, newtonian physics don’t apply to these sort of things.) ---
**Author:** ![Chocobo](https://avatars.discourse-cdn.com/v4/letter/c/898d66/32.png) [@Chocobo](https://boards.straightdope.com/u/Chocobo)\ **Post date:** [September 11, 2001, 2:22am UTC](https://boards.straightdope.com/t/photon-speed/80767/5 "2001-09-11T02:22:26Z")
> [@](#): > > \*Originally posted by xash \* > **hope someone will shed some light on this soon…** No pun intended, right? =) I think that **bouv** had it right. IANAPE (Photon Expert) but, since a photon has no mass I would think it would not need to be accelerated. ---
**Author:** ![SPOOFE](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@SPOOFE](https://boards.straightdope.com/u/SPOOFE)\ **Post date:** [September 11, 2001, 3:02am UTC](https://boards.straightdope.com/t/photon-speed/80767/6 "2001-09-11T03:02:20Z")
> [@](#): > > How do emitted photons instantaneously travel at the speed of light since they were not accelerated? It _does_ accelerate, just really, really quickly. And since it weighs, like, nothing, the energy needed to get it going is just about nil. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [September 11, 2001, 3:16am UTC](https://boards.straightdope.com/t/photon-speed/80767/7 "2001-09-11T03:16:12Z")
When an electron in an atom drops to a lower energy level it does so instantly. It doesn’t actually move from a higher orbital to lower one – it all of sudden is just there. This “quantum jump” phenomenon provoked Schrodinger to say “Jeez I wish I’d never got involved with this QM crap” (or something like that.) In any case when an electron does this trick the drop in the electron’s energy manifests itself as a photon. And the energy of the photon has to be exactly equal to the energy difference between the orbitals. Since the energy is released instantly the photon must instantly have this energy and the only way an electron can have any energy is to travel at c.