Light is always represented with the letter C.Where did you get this formula from?
I don't really understand the decay factor question, but C is the speed of light and as far as I know that's still considered to be an universal physical constant.
The way you are asking the question suggests the following answerable question:
Given a point source, does the intensity of light decrease over distance in the same way the intensity of ripples in a pond from a stone dropped in the center get smaller with distance?
The answer to that is "Yes," and the rate of decrease of the intensity of light over distance from a point source as measured by energy per unit of area perpendicular to the wave propigation is known to follow a formula known as the inverse square law.
The law says that given a total power output from your point source of P, then at a distance of r from the source, the total intensity (power per unit area) is given by the total power at the source, divided by the area of a sphere of radius r centered on the source. In other words, the light energy propigates spherically and uniformally from the point source, and intensity decreases over distance inversely proportional to the square of teh distance. Hence, the "inverse square law."
I just know that with fluorescent light bulbs, it takes them ages to warm up!
Water and air molecules have mass, photons do not.
Light is electromagnetic energy. A photon is a unit of measure of that energy. For the purposes of equations, light can be represented as particles or as wave packets, but those are modeling considerations of how we represent energy.
Sound waves and waves in water are mechanical energy. Mechanical waves degrade over distance because of friction, and the energy is transformed from mechanical energy to heat. Eventually all of the potential energy (represented by whatever is dropped into the water, or making a sound) which has been converted into mechanical energy will be converted again to heat or preserved as potential mechanical energy within a system. That's how mechanical energy functions.
Light waves already are energy.
The rules of conservation of energy tell you that energy can not be created or destroyed. That's why when you release potential energy to kinectic energy, the total energy in a mechanical system remains constant. The fact that mechanical energy tends to convert to heat energy due to friction is why we don't have perpetual motion. However, to have light decay is to destroy energy unless it is converted to something else. But there's nothing to convert it too besides another form of energy.
It is possible that light can be absorbed by some material or another, but what happens then is that light is converted to heat. That process can change the wavelength of the light. What happens when you look at a blue object, after all, is that those wavelengths that are blue are being reflected and other wavelengths are being absorbed. But that is not decay, that is simply energy conversion.
That's misapplying Einstein's equation. Total energy is conserved in a system where energy and mass are being converted, such as a nuclear reaction. It does not say that energy _HAS_ mass.
Mass is related to energy because the invariant mass of an object is defined by the equation: m = sqrt{E2/c4 - p2/c2}
Where E = energy, c- the speed of light, p equals the momentum. It is concievable that you could construct a relativistic frame of reference (a box with perfect mirrored surfaces where absolutely no conversion of light to heat could ever take place), and place within that box some light. In principle the light would add relativistic mass because of the total momentum in the box.
But relativistic mass is not what is meant by 'mass' in the sense of "weighable substance," and the distinction is non-trivial!! What would be being measured in our experiment is not substance, but Energy!
The important point is that E=pc for light. So based on our equation:
m2 = E2/c4 - p2/c2 = (pc)2/c4 - p2/c2 = p2c2/c4 - p2/c2=p2/c2- p2/c2 = 0
E=mc^2 is not the full equation, though. E^2 = p^2 * c^2 + m^2 * c^4 is more complete (E is energy, p is momentum, m is mass, and c is the speed of light). For most objects, p is near enough to zero (comparatively, p << m*c) that we can simplify this to E = m*c^2. For light (and other massless particles), m=0 and E = pc. Light does have momentum (which is related to its wavelength), and it is this momentum which exerts pressure.
Remember, pressure is force over an area and force can be expressed as a function of momentum: F=m*a, but also F=(dp/dt), which if your not familiar with the notation is the basically the change of momentum with respect to time. So if a massless particle changes its momentum when it strikes a massive object, then a force is exerted. And if a force is exerted over an area (even a small area), then there is a pressure.
Cwwiss, yes energy can exert pressure from momentum alone.
Omnipaul's explaination is dead on.
And it's not correct to say a photon doesn't exist. But it is incorrect to think of it as a particle. It can be treated as a particle for some modeling considerations. But it is not a particle. It can also be treated as a wave packet for some modelsing considerations, but it is also not a wave. It is energy. Perhaps the best way to think of a photon is as an irreducable event.
not to be rude but how is that a person who can understand all that has a rating that low? (kingpatzer)
The notion of a rest mass for a photon misses the point that photon is not a particle except for modeling purposes. It is a wave packet of energy.
Our experiments tell us that a very, very small resting mass could be stil be measured. However, that tells us something about our tools, not about photons :)
A photon "at rest" wouldn't be a photon. And if it has any mass at all, it can't move at the speed of light in a vacuum. And the standard model will break. The real question is if photons interact with the Higgs field. If they do, then in some sense they have relativistic mass -- but that mass isn't what one normally means when they talk about mass - it doesn't mean physical substance. It just means that energy is interacting with the Higgs field in some way as the photon moves. If we could stop the photon from moving, without converting that energy in anyway, then the energy would have to do something -- so we'd have some sort of energy/matter conversion in order to conserve energy. But that is entirely a theoretical question that doesn't say anything about reality because we can't remove all momentum from light energy without energy loss in reality.
Remember models aren't the universe. The upper limits of mass that you are seeing are the result of the lower limits of our precision in measuring effects predicted by Coulomb's law. That is, the model doesn't say the photon can have mass. The experimental limits of measuring extremely small events is simply what it is.
And no, it isn't the decay factor you're looking for. The decay factor you're looking for can't exist an the law of conservation of energy hold.
not to be rude but how is that a person who can understand all that has a rating that low? (kingpatzer)
ROFL - not rude, good question :)
Well, unlike math, which I've been doign all my life, I only have really been playing chess seriously for a few years. I played a little bit in my 30s and got myself up to 1400 after 2 or 3 years of playing occassionally. I took a decade off due to other interest, and then came back when my OTB rating plummetted to 1200. I am getting better though, my OTB rating has gone from 1200 to over 1500 in the last year. And I'm playing seriously for the first time in my life.
So I'm going through all the learning curve stuff one would expect. And I suck, 'cause, well, relatively novice players suck!
And anything that approaches blitz is simply too much for my old adled brain to deal with :)
As you are a relative novice to chess I am to Physics (pretty obvious I suppose)and I just can't get my head around the idea that a photon of light can travel for billions of years without experiencing some 'decay' .To me that would be perpetual motion which is impossible.
You are confusing Newtonian and Einsteinian models of thinking. Don't think of light as a thing. It's not a thing. It's electromagnetic energy. You already accept that energy can't be lost.
A machine can't have perpetual motion because there is always some friction in reality. That friction means energy comes out of the system as thermal energy.
The question you have to ask is what would happen to the energy that woud be lost by the light's "perpetual motion," it would have to be converted to some other form of energy. But light isn't interacting with anything. It's not experiencing friction which would cause it to slow down (again, potential interactions with the Higgs field not-with-standing, but if light does interact with the Higgs field in a meaningful way, we don't know how or what that implies yet), what would be the mechanism for energy loss, and where would that energy go?
Einstein suspected the big bang model based on the 'red shift' was flawed.Carl Sagan posed the question that all the 'red shift' may not be due entirely to bodies moving away from us. Dark matter,Dark Energy, string theory all seem to have been born out of the need to prop up the big bang theory.
Einstein noted that his model didn't allow for a stable Universe. We have no experimental data to suppose the Universe is stable. Einstein added the famous cosmological constant in order to achieve a stable universe. When it was discovered the universe was expanding, the need for the cosmological constant went away.
Dark Energy and Dark Matter have been proposed to account for various observed phenomenon. Basically, there is reason to suspect that space is stretching, that is, the Universe expansion is accelerating, and we don't know why or how. "Dark Energy" is the proposed means of solving this observed phenomenon. "Dark Matter" is proposed to account for observed gravitational behaviors on a large scale that can't be explained by other means. Basically, it's a fudge factor in the model. We know there's mass out there, or something that behaves like mass with respect to the bending of space-time, but we can't observe what it is yet.
These aren't born out of a need to prop up the big bang. They are born out of a need to explain observed events.
We have no idea what they might be..not even a clue! Isn't it much more logical to say that the 'red shift' is due to light decaying and that there aren't distant galaxies moving away from us at nearly the speed of light? That the only reason over 90% of the universe is 'missing' is because we just can't see it ?That the universe is many times larger than the observable universe? That the universe is much older than 13.7billion years?
The thing is we do have a clue what these things might be. We can observe the effects of dark energy and dark matter.
Humour me - IF the red shift was due to light decaying in the way I have suggested ,based on observable measurements for 'red shifts' is it possible to formulate an equation to calculate that decay factor and if yes what would it be ?
No, because it breaks the standard model. You have to start back and square one and explain why we observe what we observe in the experimental data at the quantum level. In other words, you can't just say "let's pretend that energy disappears from the Universe over time, but nothing else changes," and then still have anything else work right beyond Newtonian level phenomenon.
One more thing. My old maths teacher said after every question look at it the answer you've got and ask yourself "does it look right"?
Whatever the maths says..whatever the Theory says..to me ,
it just don't look right !
Again, you presume that energy can be treated the same as mechanical motion with respect to expected outcomes, and it just isn't so.
Kingpatzer wrote -
The question you have to ask is what would happen to the energy that woud be lost by the light's "perpetual motion," it would have to be converted to some other form of energy. But light isn't interacting with anything. It's not experiencing friction which would cause it to slow down (again, potential interactions with the Higgs field not-with-standing, but if light does interact with the Higgs field in a meaningful way, we don't know how or what that implies yet), what would be the mechanism for energy loss, and where would that energy go?
But surely light does interact and lose energy..gravitational lensing for example shows it does react with it's surroundings...there's your 'friction'.
That isn't what gravitational lensing is. Gravitational lensing is simply the effects of gravity as expressed in the shape of space, it is not a substance that induces friction. It doesn't convert light from one form of energy to another.
Light's only known interactions with matter are pretty straight forward -- reflecting off of something and thus converting some energy to heat and being absorbed by something and thus converting some energy to heat.
When it was discovered the universe was expanding, the need for the cosmological constant went away.
The 'observable events' are seen from the perspective of the 'standard model' . What if the 'standard model' is wrong? All of the observable data suggests a steady state universe to my eyes. And if not exactly a steady state certainly not a big bang.
While I understand this stuff, I'm a really just a diletante. However, my brother-in-law got is Doctorate from Jesus College Cambridge as a Marshall scholar, and he's currently a tenured professor of astronomy. I know he's always looking for his next paper topic, so if you have actual observational data that is explained by a steady state universe and in no other way, and are really serious, PM me and I'll get you in touch with some very respected astronomers to co-author a paper.
The thing is, with the Higgs Boson having been observed, if you really have something, you do realize that you'd be in the running for a Nobel prize, right? Because you'd have data that demanded a paradigm shift on par with the fallout from MIchelson-Morley.
My guess is that what you're really saying is that you can't wrap you head around what the current state of physics implies on these topics so you want it to be wrong, but that you're coming at it from a very non-expert position and that's ok. But if I'm wrong, and you really have something, and you're looking for co-authors, PM me.
I have enjoyed our discussion on this topic.You have helped me fill in some of the gaps in my understanding for which I thank you.Your knowledge is obviously far more extensive than mine on the subject.Thank you for your time and patience it's much appreciated.
Pity you can't humour me and create that equation which is beyond my maths...perhaps your's too?
While I'm a reasonably competent guy, creating an entirely new make-believe model of the universe is a tad beyond my capability :)
I think i'll go and play some 1 minute chess..much easier,I don't have to think about that..I can smell my way :D
"Light doesn't "decay", it attenuates".
Something I just read, but don't remember if it was discussed above.
Why do you want the universe to be steady-state?
I have been trying to give this some serious thought, rather than rejecting it outright, but I can't think of anything that would create this decay factor that you want.
Would it be intrinsic to the light? The problem with this is that then the light would have a time-dependent energy in its own reference frame. But from the reference frame of the light, no time passes, so there is no opportunity for any kind of time-dependent decay.
So then the decay would have to be imposed on the light from somewhere else. But where would that come from? Escaping a gravitational well produces a red-shift, but that is already a known property and is already incorporated into current models, so it wouldn't really work for your purposes. I can't really think of anything else that we know about that might affect light in such a way.
So now we're left with some still-to-be-determined outside force that does this to light and not affect anything else. Now, that might seem unlikely, but light is the only massless particle that operates on macroscopic scales (gluons are also massless, but they operate on sub-atomic scales). If gravitons exist (we have no current evidence for them), they would also be massless.
What you're effectively talking about, then, is the Aether - a concept whose death knell arrived when the Michelson-Morley experiment failed. Admittedly, the Aether as theorized back then operates differently than what you're proposing.
If I might ask, what exactly are your problems with the big bang theory? What are these "illogical and counter intuitive precepts" that you mention? And I might mention that there is a lot in physics that is counter-intuitive, but that's mainly because our experiences are so limited. When was the last time you experienced extreme gravity or traveled at speeds near that of light? Similarly, when have you ever experienced what things are like at the extremely tiny (sub-atomic) scales? Obviously those are rhetorical questions as we aren't capable of such experiences on a personal level, but things operate very differently than we're used to in those situations.
I appreciate your not rejecting this question as it has become important to me over the years. I can well understand you wanting to as i'm sure most astrophysicists would . How can a particle like a Photon which has no apparent mass decay when it can't interact with anything? Well, we don't know how it reacts with the Higgs field..it's possible that could lengthen light's wave length?
Carl Sagan suggested in a throw away comment in one of his broadcasts many years ago now that the 'red shift' may be due to something other than a fast receding body which echoed my own scepticism .I'm just trying to find what that 'other something' might be. In my twenties I read in a book that some galaxies are receding at close to the speed of light! When Carl Sagan expressed the possibility that there maybe another reason for this 'red shift' it planted the seed that the Big Bang theory may be wrong.
Einstein was sceptical of the BB theory (taken from Wiki)
“
Einstein, while not taking exception to the mathematics of Lemaître's theory, refused to accept the idea of an expanding universe; Lemaître recalled him commenting "Vos calculs sont corrects, mais votre physique est abominable"[11] ("Your math is correct, but your physics is abominable."
Now I know there have been many experiments and many observations to 'confirm' this model but I believe there is a fundamental flaw in our understanding when it comes to light. There are many observations which seem to be at variance with the Standard Model.
If light has some kind of decay over distance then we could have a steady-state universe or something 'non big bang', at least.
I posted this question here because there might be some open minded well educated people who might be able to help me with this theory of mine and so it's proved to be.Both you and KIngpatser have helped a great deal.
Has light got a decay factor in exactly the same way as ripples in a pond get longer over distance and time?
There you go. :) ;)