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#6733 - 04/27/06 10:03 PM Energy producing light speed.
jjw Offline
Superstar

Registered: 09/07/05
Posts: 636
Loc: USA
Energy source for Light:

A curious circumstance has troubled me about the energy that produces light. The point being why does a greater energy source produce more light, and very likely more heat, but always produces light of the same speed. When dealing with stars we have some interesting comparisons.

http://news.bbc.co.uk/1/hi/sci/tech/4164365.stm

Astronomers have been measuring some distant stars and they find a lot of big guys out there. Our sun has a diameter of about 864,000 miles and we know what it can do. One of the recently discovered red giants is believed by the group to be 1.5 billion km in diameter. Translated into miles that is a diameter of 932,055,000 miles. Forget the difference in volume; the red giant is 1079 times larger in diameter than our sun. This is just one of the larger stars.

I tried to find energy determinative for comparing the outputs between these objects and did not succeed. The point here is why would such a giant start producing so much more energy create light of the same speed as our star produces? I know some one can answer this.

jjw

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#6734 - 04/27/06 10:23 PM Re: Energy producing light speed.
dr_rocket Offline
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Registered: 12/06/06
Posts: 196
Loc: Palo Alto, CA, USA
Greetings jjw004,

I'am not exactly sure what your question(s) is (are.) If I am reading you right, you seem to be asking about a relationship between the brightness, temperature and mass/size of stars.

If that is, in fact, what you are asking about I would suggest having a look at this site:

http://zebu.uoregon.edu/~soper/Stars/hrdiagram.html

This is a good page on the Hertzprung-Russell diagram which deals with the kind of relations you seem to asking about. It also has several interseting links.

It provides a good starting point to learn about the evolution of stars and quite a bit more.

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#6735 - 04/27/06 11:28 PM Re: Energy producing light speed.
DA Morgan Offline
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Registered: 10/17/04
Posts: 4136
Loc: Seattle, WA
jjw asks:
"why would such a giant start producing so much more energy create light of the same speed as our star produces?"

Because all photons, all light, travel at the exact same speed in a particular medium, for example the near vaccuum of space.

This fact is one of the most fundamental assumptions made by Einstein and repeatedly proven by experiment.

Brightness is just more photons per unit of area.

The energy of an individual photon is measured as its wavelength (or color).

Does this help?
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#6736 - 04/28/06 12:40 AM Re: Energy producing light speed.
jjw Offline
Superstar

Registered: 09/07/05
Posts: 636
Loc: USA
Thank you Guys:

dr rockets link was interesting and concluded what common sense would suggest.

"The star's mass determines what the temperature and luminosity is during the star's main sequence lifetime.
More mass -> hotter.
More mass -> more luminous.
Also, more mass -> bigger. "

DA adds, More mass not producing faster photons.

I had a book that provided the formula for calculating the escape velocity and I must get it to figure what the escape velocity would be from a star 1 million times more massive than our sun. This could be hypothetically enlarged to find an escape velocity that was so high it would border on a Black Hole but just miss. In that situation I can better understand why light would blast off instanly at it's top speed with no deterent resulting from the stars gravity.

Thank you fellas. I will keep working on it.
jjw

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#6737 - 04/28/06 12:45 AM Re: Energy producing light speed.
DA Morgan Offline
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Registered: 10/17/04
Posts: 4136
Loc: Seattle, WA
I'll agree with Rocky that bigger determines luminosity but bigger may also be cooler. Many stars, such as red giants, are very large ... and quite cool.

For calculating escape velocity the mass of the star is irrelevant. It is rather tha mass per unit of volume that matters.

Take, for example, a massive star. Light escapes. Compress that star into a black hole and light can not.

HTH
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DA Morgan

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#6738 - 06/02/06 05:23 AM Re: Energy producing light speed.
jhmar Offline
Junior Member

Registered: 05/25/06
Posts: 10
Loc: uk
The point being why does a greater energy source produce more light, but always produces light of the same speed.

Replies to date refer you to Quantum Theory (QT). Open any starter text on QT and in the introduction you will find a comment to the effect that QT has no complete interpretation. QT physicist operate in the belief that if you can compute it, you understand it.
This means that there is experimental proof and a mathematical theory that states the known facts about 'light'; but there is no explanation of how or why it operates in the known manner.
This question of interpretation (reasons stated in words) is the one I am working on. You can see the start on the webpage I referred you to on the waves discussion. I hope to open a discussion on this when I have made a little more progress.

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#6739 - 06/02/06 10:25 AM Re: Energy producing light speed.
dehammer Offline
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Registered: 03/23/06
Posts: 1089
light is either a wave that behaves like a particle or a particle that behaves like a wave. either way, it has wave characteristics.

sound is another wave. sound travels the same speed though a given medium, at a given pressure, at a given temp(er)ature.
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#6740 - 06/04/06 01:19 AM Re: Energy producing light speed.
jjw Offline
Superstar

Registered: 09/07/05
Posts: 636
Loc: USA
Energy source of light.

No matter how we approach this issue we are confronted with the standard conclusions.

Namely, Light fro any source in a vacumn will always travel at the same speed.

Suppose a hundred years ago or more some brain claimes that a vacumn placed a limit on how fast stuff could travel. That makes sense. I think it makes more sense than to argue that all sources of energy must produce acceleration of stuff at the same velocity. The vacumn is a constant the sources of energy are no.

Thank you for the input.
jjw

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#6741 - 06/04/06 01:21 PM Re: Energy producing light speed.
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
there is also a theory that we can only measure things in our vicinity, which is not constant in the universe.

imagine a early day Polynesian weather man. at sea level, the air pressure does not change that much, nor does the temperature. the result is that he could only forecast things that are comparative to that area. he could never (unless he was in one of the rare areas with mountains high enough which he is not in this example) predict snow. nor could he predict things that happen with lower air pressure or as a result of the air stream, since it would always be very far north or south of him.

according to this theory (not widely held, mind you) the sun and near by stars create a certain "pressure" in the vacuum and a certain "temperature" within the gravitational field of the sun. we can only measure the speed of light and other things with in the range of measurements
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#6742 - 06/07/06 05:22 AM Re: Energy producing light speed.
jhmar Offline
Junior Member

Registered: 05/25/06
Posts: 10
Loc: uk
light is either a wave that behaves like a particle or a particle that behaves like a wave. either way, it has wave characteristics.

No matter how we approach this issue we are confronted with the standard conclusions. Namely, Light fro any source in a vacumn will always travel at the same speed.

There is an assumption that is open to challenge in that it is being assumed that vacuum is stationary, while something other than vacuum moves.

Look at the other possibility. Consider that vacuum exists in the form of particle fields that move through 'something' (the vacuum force carrier).

Speed is determined by force carrier density. The vacuun field does not loose momentum it slows down and speeds up according to the density of the force carrier. A photon approaching a black hole slows down. If it escapes it speeds up because vacuum field momentum is conserved. But in current interpretation, because the particle is something momentum is lost during deceleration and cannot be replaced without cause. Whereas a particle size vacuum field obeys the rule v=f/d (v=speed; f=field force; d= background density).
In reality particles (gravitons) form the background and their density is determined by the presence of other particles (mass distorts gravity).

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#6743 - 06/07/06 04:58 PM Re: Energy producing light speed.
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
that would explain many things that others cant really explain. such as the fact that the universe appears to be expanding at an accelerated rate.

if the force carrier was affecting its speed light would be traveling faster between the stars, making it appear that they were moving away at accelerated rates. by the rate of speed the photon is traveling in the vicinity of our sun and the earth, the distance stars would constantly be off and the rates would be getting worse.
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#6744 - 06/07/06 10:23 PM Re: Energy producing light speed.
jjw Offline
Superstar

Registered: 09/07/05
Posts: 636
Loc: USA
dehammer?

"there is also a theory that we can only measure things in our vicinity, which is not constant in the universe."

If you have a link for that I would like it.
Note that it sounds like a quote from my book.
I do not deal with temperature, I blame the density of the gravitational field. Curious.
jjw

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#6745 - 06/08/06 05:20 AM Re: Energy producing light speed.
dehammer Offline
Megastar

Registered: 03/23/06
Posts: 1089
Quote:
Originally posted by jjw004:
If you have a link for that I would like it.
Note that it sounds like a quote from my book.
I do not deal with temperature, I blame the density of the gravitational field. Curious.
jjw
no, sorry, it was something i picked up pre internet. i had a science teacher that believe that we should learn about other theories even if there was no other evidence, just so that we would have an open mind about possibilities.
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