# No light without electrons? **URL:** \ **Category:** Factual Questions\ **Created:** [October 10, 2001, 8:15pm UTC](https://boards.straightdope.com/t/no-light-without-electrons/86649 "2001-10-10T20:15:40Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![howardsims](https://avatars.discourse-cdn.com/v4/letter/h/e8c25b/32.png) [@howardsims](https://boards.straightdope.com/u/howardsims)\ **Post date:** [October 10, 2001, 8:15pm UTC](https://boards.straightdope.com/t/no-light-without-electrons/86649/1 "2001-10-10T20:15:40Z")
As I understand it, an atom emits a photon when one of it’s electrons moves to a lower energy state. Now if an atom has had all of its electrons stripped off as happens in a plasma (and I think this is the case in the sun) the atom can’t emit a photon? So the sun should be dark? Where am I going wrong with this? ---
**Author:** ![Bob\_Scene](https://avatars.discourse-cdn.com/v4/letter/b/e19adc/32.png) [@Bob\_Scene](https://boards.straightdope.com/u/Bob_Scene)\ **Post date:** [October 10, 2001, 8:31pm UTC](https://boards.straightdope.com/t/no-light-without-electrons/86649/2 "2001-10-10T20:31:05Z")
There are other ways for light to be produced besides by an electron changing energy levels in an atom. Any accelerating (or decelerating) charge gives off electromagnetic radiation. Free electrons and/or protons radiate if they’re being accelerated in a particle accelerator, for example. ---
**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\ **Post date:** [October 10, 2001, 9:54pm UTC](https://boards.straightdope.com/t/no-light-without-electrons/86649/3 "2001-10-10T21:54:16Z")
Photons are also emitted in many nuclear reactions, including many of those going on the Sun’s core. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [October 10, 2001, 11:17pm UTC](https://boards.straightdope.com/t/no-light-without-electrons/86649/4 "2001-10-10T23:17:04Z")
The photons produced in the fusioning core are gamma rays, which of course are invisible, and can do bad things to a person. (Ionizing radiation) However, it takes about 10^7 years for this radiation to escape from the star and during this time the gamma ray photons will have interacted with other particles countless numbers of times, and on the whole they will have lost most of their energy. When this energy is finally on its way to Earth most of it will have a frequency in the visible light band. ---
**Author:** ![JS\_Princeton](https://avatars.discourse-cdn.com/v4/letter/j/57b2e6/32.png) [@JS\_Princeton](https://boards.straightdope.com/u/JS_Princeton)\ **Post date:** [October 10, 2001, 11:28pm UTC](https://boards.straightdope.com/t/no-light-without-electrons/86649/5 "2001-10-10T23:28:53Z")
Ring, I don’t think you have your facts straight. As I understand it, most of the visible light we see comes from ionization of H-, a bizarre molecule (to all but organic chemists) that sits in the chromosphere of the sun and happily emits the visible light that illuminates our world. In fact, though there is plasma in the sun, the entire sun isn’t plasma! That would be ludicruos. Photons are not exclusively emitted by electrons changing energy (though that is certainly a big bunch of them that we see). Other ways to get light are expounded upon in previous posts. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [October 11, 2001, 12:08am UTC](https://boards.straightdope.com/t/no-light-without-electrons/86649/6 "2001-10-11T00:08:42Z")
> [@](#): > > JS Princeton wrote: > > Ring, I don’t think you have your facts straight. > > As I understand it, most of the visible light we see comes from ionization of H- And what do you think causes this ionization? > [@](#): > > Ring wrote: > > However, it takes about 10^7 years for this radiation to escape from the star and during this time the gamma ray photons will have interacted with other particles countless numbers of times, and on the whole they will have lost most of their energy.