Light

[astrolabe]

Hello All,

If I in anyway aided in the decision to lock the DE/DM thread then I apologize. For me it's sometimes irresistable to throw in a quip or two whenever I feel like it, sometimes this Forum can get wound up pretty tight- call me impulsive but that's the way I am. Mr. Diffuser, yep, that's me alright. Now for the topic:

1.) Can there be light without heat?
2.) Would there be light without DM?
3.) There are free electrons, is DM free Gravitons (as elusive as they are)?

Einstein believed that space and the matter in it was an extension of visible matter. How would one perceive DM differently if his statement was valid- and is it valid?

[bystander]

1.) Can there be light without heat?
2.) Would there be light without DM?
3.) There are free electrons, is DM free Gravitons (as elusive as they are)?

1. If by light you mean electromagnetic radiation (emr) and not just that narrow band we humans call visible light, and if by heat you mean energy (of which heat is just one form), then I would say no, light can not exist without heat.

2. Since DM only interacts with baryonic matter through gravity and not emr (DM by definition has no emr), then I would say yes, light can exist w/o DM.

3. Gravitons have not been demonstrated to exist, so their properties aren't really known. As to what DM is made of, we don't know that either. It has mass and affects gravity. Could it be free gravitons? Maybe, I certainly don't know.

Just my opinion, not a definitive answer.

[astrolabe]

Hello bystander,

It maybe just your opinion as you say but I value it.

In a previous thread it was brought out that Large BH are cold places which allowed me to pursue the idea of that being one of the factors in why light is not emitted from them. I of course realize that the EM spectrum is wide with visible light being a narrow band and that energy takes many forms, heat being one form with a gradient from theoretical absolute zero to many millions of degrees and perhaps beyond. I certainly have no issues here. So I was mostly curious about the narrow visible light band.

It is without doubt that variations in heat energy do cause light to shift within the visible band from near ultraviolet to near infrared. So obviously I skipped a lot of steps in my mind and ended up asking a very pared down version of that huge, beautiful and self gratifying image that I had of the cosmos- it was GLORIOUS....AND THEN I WAS GOING TO RULE THE WORLD!!!!.........(cough,cough,wheeze)..ugh!...(pant,pant,pant) whew, (puff,puff,puff) man, (puff,pant,puff) wow, where did all that come from? I need a nap.

Anyway, the idea that visible light needs a heat source was what I was getting at along with DM's possible role as a medium even though I know it does not interact with it. I imagined it to be along the same concept as needing molecules to transmit sound waves. but it would not seem to be the case.

My last question was in hopes of solidifying the idea of a light/DM connection because of the phenom of lensing and therefore connect a strong gravity well and its associated Dark Matter concentration with the redirection of the light path originating from behind the Coma Cluster or the Abell group for example.

Just my thoughts really, wandering.

[makc]

the decision to lock the DE/DM thread

I locked it because it went off topic, if enough people want it back, I will re-open. This lockage stuff is pretty random, but I had the feeling noone is going to say anything new any way... but this can be said about half of threads.

[neufer]

There are free electrons, is DM free Gravitons (as elusive as they are)?

Gravitons have not been demonstrated to exist, so their properties aren't really known. As to what DM is made of, we don't know that either. It has mass and affects gravity. Could it be free gravitons? Maybe, I certainly don't know.

Gravity and electromagnetism act over very long distances; hence, their quanta must be massless and travel at the speed of light.

1) Being massless means that any gravitons & photons left over from the big bang stopped contributing significantly to the gravitational field of the universe a long time ago.

2) Being massless and traveling at the speed of light means that gravitons & photons cannot significantly contribute to the gravitational field of galaxies which has provided the best evidence for DM.

[astrolabe]

Hello neufer,

Good. Thanks.