Naked Science Forum
On the Lighter Side => New Theories => Topic started by: McQueen on 06/04/2024 03:48:31
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Olber′s paradox states that the sky is not uniformly bright although it contains, to all intents and purposes, an infinite number of stars. In other words going strictly by the facts, the night sky should be as bright as day, the paradox lies in the fact that this is not the case. But does the present day explanation that Olber′s paradox exists because the Universe is expanding and that light from distant stars has not yet reached us, make sense?
Imagine walking on a moor on a moonless night, the power is out and only candles are available. Everything around is in darkness, even the path is very indistinct. Suddenly, as you look up you see the light from a candle. There are several weird things about this light, (1) the first is that only the candle flame is visible nothing around it is visible, the reflected light from objects close to the candle cannot be seen (2) if you take a step back the light from the candle disappears, it is no longer visible. What is happening? The first question to ask is: Why does the light disappear? Obviously, the answer is that there is not enough intensity in the candle light to travel further, the light from the candle can travel so far and only so far before its intensity becomes too low to detect. The question is why; power is still available, the candle is still burning, obviously enough tallow and wick is present to keep the candle burning, why then does the light stop at the precise boundary that you have perceived? How is it that given the fact that the light follows the inverse square law as it travels, meaning that it spreads out directly according to the square of the distance travelled (isotropic light), that only the candle is visible, nothing around your immediate surroundings is made visible by the light from the candle. Why? Surely, if light spreads out according to the direct square of the distance travelled, some small portion of the surroundings should be illuminated? But this is not the case, the light seems to be visible as a point of brightness and nothing more. What is happening? For anyone, standing on the circumference of the place where you are standing, and with the candle at the centre, the candle flame is clearly visible, but nothing else? Could this have anything to do with the rectilinear nature of light? Numerous experiments have shown that the energy of the photons detected on the circumference that the light covers all have the same energy and therefore intensity. One thought that comes to mind is that light varies not only in frequency but in intensity and in this particular instance, only the most intense light makes it your location.
Surely, this is a far more cogent explanation for Olber′s paradox than to think that the Universe is expanding so rapidly and so fast that the light from distant stars never reaches us? Namely, that for a given amount of power, light travels a given distance, it cannot go any further than that power allows. Increase the power and increase the distance over which light is detectable, keep the power at a fixed level and it doesn′t matter for how long that light is on, it cannot travel one iota further than the power supplied to it allows.
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Namely, that for a given amount of power, light travels a given distance, it cannot go any further than that power allows. Increase the power and increase the distance over which light is detectable, keep the power at a fixed level and it doesn′t matter for how long that light is on, it cannot travel one iota further than the power supplied to it allows.
That would imply that single photons suddenly poof out of existence for no obvious reason. It's not like photons consume energy to move.
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That would imply that single photons suddenly poof out of existence for no obvious reason. It's not like photons consume energy to move.
Surely one of the implications of everything that has been said and observed is that independent photons do not exist, in the sense of always being detected at a given distance from the source and at every point at that distance with the same energy and intensity?
If your argument for independent photons were true then the inverse square law would not be true.
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Your candle analogy is flawed. The problem is that your eyes have a limited dynamic range, so you cannot simultaneously accommodate the brightness of the candle flame and the very dim radiation scattered from its surroundings. If you eclipse the primary source and use a night-vision scope, you can see the man holding the candle.
Problem with stars is that "the man holding the candle" is much smaller than the star, and a long way away, so searching for distant planets isn't easy, but they are there and they do reflect light.
to all intents and purposes, an infinite number of stars.
is clearly nonsense.
You can see the void between the stars so however many there are, the angular density of stars at any point on a sphere is obviously not infinite.
Rectilinear propagation means that even if there are stars at a greater radius, they will appear less bright and eventually disappear below the noise level of your detector
And stars do not have an infinite life of constant brilliance.
In short: no paradox, because the primary axiom is incomplete.
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Olber′s paradox states that the sky is not uniformly bright although it contains, to all intents and purposes, an infinite number of stars.
No.
It does more or less the opposite.
Here's what WIKI says
"Olbers's paradox, also known as the dark night paradox, is an argument in astrophysics and physical cosmology that says that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. "
Olber was clever enough to recognise the importance of the most commonplace observation; it gets dark at night.
That tells you that either the universe is not infinite in physical extent or it's not infinitely old or we live in a very weird bit of it- the only bit with stars.
Other observations say that the resolution of the "paradox" is that the universe is finite in age- about 14 billion years.
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Namely, that for a given amount of power, light travels a given distance,
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No.
It does more or less the opposite.
Here's what WIKI says
"Olbers's paradox, also known as the dark night paradox, is an argument in astrophysics and physical cosmology that says that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. "
Olber was clever enough to recognise the importance of the most commonplace observation; it gets dark at night.
While I appreciate all of the comments made so far, they are unfortunately rather dated, and also miss many of the significant points that were made about the propagation of light. Some comments have been, made without thinking at all, a consequence I suppose of age. Granted Olber′s paradox IS old and IS based on Isaac Newton′s premise that the Universe was both static and infinite in extent. Today the view (well supported by empirical evidence) is that the Universe is both finite in age and extent. But what is the modern take on Olber′s paradox?
Olber′s paradox was the question of why the night sky is dark if the universe is infinite and filled with an infinite number of stars. A fairly understandable point of view. However, in modern cosmology, this paradox is resolved by the understanding that the universe is not only expanding (i.e., not static), but also finite in age. This means that given the fact that the Universe is expanding, that light from distant stars has not had enough time to reach us, and also that the universe has not yet had enough time to fill with light from all the stars. Additionally, the universe is filled with cosmic dust and gas that absorb and scatter light, contributing to the darkness of the night sky.
My OP merely pointed out that there may be other contributing factors, which it is surprising to note, have not received the notice due them.
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My OP merely pointed out that there may be other contributing factors, which it is surprising to note, have not received the notice due them.
It is not surprising at all considering that the "other contributing factors" you talk about are directly counter to established physics. If you had a better understanding of physics you would see that your ideas are seriously flawed.
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Olber′s paradox was the question of why the night sky is dark if the universe is infinite and filled with an infinite number of stars.
To which the obvious answer is N < ∞.
A less obvious answer is that there are different sizes of infinity. The number of stars may be a denumerable infinity but (by observation) they are sparsely embedded in a nondenumerable continuum that is necessarily larger. Nothing new here - think integers embedded in real numbers.
Either way there is no paradox.
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Calverd's Paradox: If I am infinitely sexually attractive, how can I walk to the shops without fighting off hordes of lustful women?
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and also miss many of the significant points that were made about the propagation of light.
I think I made the only point needed.
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Surely one of the implications of everything that has been said and observed is that independent photons do not exist, in the sense of always being detected at a given distance from the source and at every point at that distance with the same energy and intensity?
If your argument for independent photons were true then the inverse square law would not be true.
Photons have been detected, so we know they exist. The inverse square law is still approximately true because there are lots and lots of photons being emitted by stars.
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Photons have been detected, so we know they exist. The inverse square law is still approximately true because there are lots and lots of photons being emitted by stars.
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always being detected at a given distance from the source and at every point at that distance with the same energy and intensity?
They aren't. An isotropic source emits equal intensities in all directions on average (definition of isotropic) but at very low intensities you can see their random arrival. Obviously if they are all generated by the same process they will have the same energy. Think machine gun bullets - all identical, all independent, and statistically distributed as 1/r^2 if you pan the gun around smoothly.
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If one just panned said machine gun the distribution function would be 1/r. If one panned and tilted it then 1/r^2 would be correct. As regards the OP's original question I have heard that under ideal circumstances the human eye can detect a candle flame at 20miles(ie complete darkness+perfect vision), don't know how true this is.