If infinite, would the Universe be too hot?

[tdamskov]

<blockquote><font class="small">In reply to:</font><hr /><p>Who is to tell us that light doesn't become part of the background noise after having travelled in its own right for some 13,5 bio. years? <p><hr /></p></p></blockquote><br /><br />It does. But probably not in the way you imply. The cosmic background radiation (CMB) has a limited frequency spectrum which science interprets as visible light stretched across distance and time. Since the cosmic background does NOT spread across a large spectrum it must originate from a specific point in time when the universe was opaque, and not from a deep starfield of galaxies (which we for some reason couldn't observe). Additionally the CMB is almost completely isotropic, meaning it has the same temperature everywhere to within 100.000 in one part. An infinite universe theory completely fails to explain this.<br /><br />And so far all experiments and observations imply that light behaves the same at extreme distances as in our own galaxy or laboratories. Light doesn't "dilute", it falls off predictably.<br /><br />If the universe contains an infinite amount of matter/energy at infinite distances, why isn't it visible? Why does the CMB exist?<br /><br />Or are you suggesting an infinite expanding universe?

 

[oscar1]

"Or are you suggesting an infinite expanding universe?"<br /><br />An expanding universe yes, but not necessarily infinitely. As I see it, it has to be expanding in order for gravity and time to exist (time being the 'stretchor' and gravity being the 'contractor'). But perhaps I am 'stretching' it a bit here; this is merely my personal belief.

 

[witgenestone]

I am not inspired by science fiction, I haven't read a single story.<br /><br />Yes, your statement was blunt. That's why I posted. It's okay to not believe in "immortal" intelligence/life, but you can't falsify this with science. I agree however that my post had little to do with science, but I was not the first one.<br /><br />I posted the mind in nothingness stuff to object against that imagination is limitless. It was crappy, but hey that's life. Imagination IMO is limited to what we observe (indirectly and directly), feel and to the language that we use. I would like to see an example of unlimited imagination. Imagination is derived from imagery, see if you can imagine anything else than just a new combination of what you have experienced through the years.<br /><br />In acknowledging limits to the mind one must accept that there might be many things that we can't comprehend. But that doesn't necessarily say that we can expect something that we want. So many people here, even those criticising idealists, are in my opinion idealists. <br /><br />And Bonzelite has som good points which you can't explain away that easily. <br /><br />

 

[kmarinas86]

<font color="yellow">I am not inspired by science fiction, I haven't read a single story.</font><br /><br />NOW THAT'S WHAT I'M TALKING ABOUT!!!!

 

[kmarinas86]

<font color="yellow">Black holes won't be the solution to Olbers Paradox.<br /><br />In an infinite universe, each black hole would keep receiving light and cosmic particles for an infinite time amount of time, which means they would keep growing in size/weight.<br /><br />Black holes cause lensing which should be detectable if they were obscuring light. Unless one assumes that the universe only contains large amounts of black holes at extreme distances (a backdrop). Oops. There goes the basic scientific assumption of an isotropic universe </font><br /><br /><br />http://x60.xanga.com/8c8d0ae62763295026275/w66438082.jpg<br /><br /><br />What would a Gamma Ray Burst from two colliding 1 billion light year black holes or gravastars look like?

 

[alkalin]

This is my understanding of how light is comprehended by the eye. Through our aperture of the eye, the iris, there are large numbers of photons that get through, and the more of them the brighter will be the light. The retinal cells collect about one thirtieth of a seconds worth of photons at a time and this is sent to the brain. But it is also true that if there are not enough photons, then the scene will be dark, although there could still be a few getting to the retina we cannot detect, a cut off, if you will. <br /><br />As some may point out here is we can compensate with collecting more through a large aperture telescope, so we can see very dim objects nonetheless, especially if we let the telescope dwell so that photons are accumulated over time, something the eye cannot do. But this argument does not address the issue.<br /><br />So far this does not have much to do directly with olbers paradox, but these are important considerations for this issue. There are other important yet fairly straightforward physical laws to consider. Why do objects such as stars appear dimmer the further away they are. It’s because the number of photons entering a given aperture will decrease inversely by the square of the distance an object is away from us. To give more detail let’s say a star at a certain distance puts through our iris an amount of photons we label as P. Place this same star twice the distance from us and our iris is now collecting one fourth of P in the same time period. The reason this is true is that light is traveling out from a star in ever increasing photon separation so increasing the volume the light occupies yet decreasing photon density. So far this should be easy for you to follow.<br /><br />There are other things going on that needs considering also, but are more speculative. But the following notion does have some fact to back it up. The universe has in many regions a thin gas that is available for forming new and small galaxies. These gala

 

[bonzelite]

i don't understand this obssession with the sanctity of olber's paradox. let's get off that train and flush it away. <br /><br />the near galaxies and nebulae do not presently reveal from behind their dust lanes all of their stars. visilbe evidence of all local stars is not occurring as they are obscured. the notion, too, that all of this dust and matter, if existing for infinity years, would then have infinity time to absorb all of the infinite radiation and then begin glowing radiant visible light in one instant is not necessarily true whatsoever and is erroneous. there is no proof or indication that the nature of interstellar dust and debris is to absorb enough light to then begin emitting it. as well, infinity dust and infinity debris in a constant state of evolution from one state to the next can infinitely obscure an infinite star field. <br /><br />stars not yet existing must coalesce into birth; this process is ongoing and could be as such in an infinite universe. a star in the process of forming today would not be seen for billions of more years were a world such as ours beyond reach of it's light source. and given the perpetuity of this process, could have infinitely yet more stars in such a condition that cannot be seen. particularly if obfuscation by dust and debris is present, which is clearly evident by observation of our local space. <br /><br />all bets are off when introduction of an infinite entity is afoot. regardless, the cosmos is not figured out but interpreted through a human vantage point of perception and invention. what is considered "impossible" is challenged year to year by even what our own technologies reveal, "baffling" us. for example, if we are so "right" about our own solar system, then Enceladus should not even exist as it does. but instead we are just "baffled" and call that world "impossible" yeah, right <img src="/images/icons/rolleyes.gif" />

 

[weeman]

<blockquote><font class="small">In reply to:</font><hr /><p> this realm can be argued to be larger than the physical cosmos. <p><hr /></p></p></blockquote><br /><br />I like how you put this about the limits of the human mind.<br /><br />I have stated in other posts that our knowledge of the Universe will always be limited to the speed of light. If it could travel through space instantaneously, we might see a Universe that exists in a completely different manner than we see today. However, due to the limits of the speed of light, we will never know if the material Universe is infinite. If indeed there are new galaxies forming at an infinite distance from Earth, we will never see them, because their light will take an infinite amount of time to reach us. Our galaxy sits in the center of a perfect sphere, that sphere is our observable universe. If humans could live for billions, trillions, or even quadrillions of years from now, the observable universe will grow bigger and bigger. However, it will always be referred to as the observable universe. This is the reason why there will always be questions unanswered about our Universe no matter how long we live for.<br /><br />I would have to say that trying to understand what lies beyond our observable universe is impossible. It would be like standing in a room with no doors and no windows and trying to come up with a plausible theory for what might exist beyond the walls. <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>

 

[bonzelite]

i hear what you are saying. <br /><br />as well, consider, too, even as pure conjecture, that <i>c</i> may not be a speed limit whatsoever. and that our knowledge of the universe, even if <i>c</i> is exceeded, may not necessarily be subject to knowing the limits, if any, of our universe's physiology.<br /><br />this is well put, by the way, actually very excellent:<br /><br /><i>"I would have to say that trying to understand what lies beyond our observable universe is impossible. It would be like standing in a room with no doors and no windows and trying to come up with a plausible theory for what might exist beyond the walls."</i>

 

[tdamskov]

<blockquote><font class="small">In reply to:</font><hr /><p>i don't understand this obssession with the sanctity of olber's paradox. let's get off that train and flush it away.<p><hr /></p></p></blockquote><br /><br />First of all, Olber's Paradox is at the core of the thread question. It's one of the basic questions cosmologists must consider. The argument of dust obscuring start doesn't work to solve Olver's Paradox since energy absorbed by dust eventually re-radiates. Here's an analogy for you. Imagine a bottle of hot water. It's perfectly (infinitely) insolated from the surroundings and does not radiate any of the heat away. What do you propose happens to the water in that bottle, if it has an infinite amount of time yet CANNOT bleed away the heat?<br /><br />Here's one of the loopholes to Olber's Paradox. The universe could be unlimited in size yet limited in age and expanding at rate which dilutes the amount of energy faster than it can propagate. Oops. For that to work, the universe must have been smaller. What's the logical consequence of a universe which is smaller the younger it is?

 

[oscar1]

I reckon Black Holes could actually create the room/space needed for continued expansion. Then, at some point in space and time, two or more BHs may collide, and 'bang', there we have a fresh and again expanding [part of the] universe; this could go on forever.

 

[vandivx]

Olbers' paradox is explained in standard astronomy by the recessional redshift which in turn is explained as caused by the Big Bang expansion...<br /><br />redshift is here regardless if one chooses to believe the BB theory or not, those who do not have the problem to explain it by other mechanisms<br /><br />one such suggested cause for the observed redshift is the so called 'tired light' phenomenon which simply says that light gets tired and so is redshifted as it travels long distances, however nobody has yet been able to come up with plausible reason and or mechanism how the light gets tired <img src="/images/icons/smile.gif" /> like people get tired as they travel in time<br /><br />point is we know next to nothing what happens to or with light in its travels (appart from it being absorbed and reemited and it direction of travel altered - bent) and I personally am fan of the tired light non explanation because it keeps all avenues open for potential new discoveries <br /><br />I also believe that the 'radiation heat' or temperature of cosmos would be the problem needing explanation even if the universe were finite<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[tdamskov]

<blockquote><font class="small">In reply to:</font><hr /><p>I reckon Black Holes could actually create the room/space needed for continued expansion<p><hr /></p></p></blockquote><br /><br />Not sure how that pertains to Olbers Paradox. Black holes are just stellar remnants with the same gravitational properties as the star it replaced. Black holes don't have any theoretical ability to create space, they just bend the surrounding spacetime into a "knot" around themselves.<br /><br />When black holes collide the should simply merge according to theory.

 

[alokmohan]

Red shift are of two types ,DOPPLER SHIFT AND GRAVITATIONAL SHIFT.

 

[tdamskov]

<blockquote><font class="small">In reply to:</font><hr /><p>I also believe that the 'radiation heat' or temperature of cosmos would be the problem needing explanation even if the universe were finite<p><hr /></p></p></blockquote><br /><br />Why, please explain?<br />

 

[kmarinas86]

<font color="yellow">Red shift are of two types ,DOPPLER SHIFT AND GRAVITATIONAL SHIFT.</font><br /><br />But there is another one: Cosmological redshift (due to the expansion of space). Doppler shift of light comes from special relativity, but gravitational redshift and cosmological redshift come from general relativity, which is the particular Einstein theory used to support the big bang (i.e. not special relativity).

 

[Mee_n_Mac]

I originally mentioned Olbers' paradox because "rfoshaug" basically asked the same question as Olbers did those many years ago. I took no position as to how to resolve the "paradox" but gave the link in case "rfoshaug" (and others) might be interested. <br /><br />Since I'm in a contrary mood today, let me play contrarian (hopefully in a good and fun way) and propose the following. <br /><br />The universe is static and infinite as She commanded it to be ! <img src="/images/icons/smile.gif" /> So to answer Olders I would say;<br /><br />1) Let me followup on a prior post(s) and say due to the inverse square law and quantum nature of light, we don't see other stars in the dark sky because the light is too dim. The probability that a photon exceeds our ability to detect it is so small that a potential detection occurs very infrequently. Indeed it may have happened but we dismissed the flicker as noise in our equipment.<br /><br />2) The interstellar gas absorbs the light from distant stars but doesn't emit BB radiation like most other matter would because it's "special". I don't know what it is but if we can speculate about dark matter being some exotic particles to solve our gravity/rotational speed problems then I can speculate about other absorbtive exotic matter to solve my distant light problem. <img src="/images/icons/tongue.gif" /> Perhaps such matter doesn't relax to the lowest energy state in "normal" timeframes. Instead it keeps receiving photons until it emits, I dunno, a x-ray. Again it only happens at infrequent intervals so we miss detecting it. Ha, so there ! <img src="/images/icons/smile.gif" /><br /><br />Now I've not explained red shift but I'm tired so that's enough to play with for now. Where am I wrong and accepted theory right ?<br /><br /> <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

 

[oscar1]

I tend to agree with you somewhat. In fact, I can't quite see where the 'paradox' comes into it. Olbers' Paradox might only be a paradox if we would know perfectly how light behaves after having covered a distance of more than 13,5 bio. light years, how exactly gas clouds absorb light, how large Big Holes can get (if they exist), etc.

 

[vandivx]

when I said problem, I didn't mean the same type of problem as when the universe would be very large in extent (excessive radiation heat) but rather that the book keeping of radiation heat that there should be won't square with the size/temperature of the finite universe (going by current or even new estimates)<br /><br />I didn't mention that tired light for nothing, I have some idea how radiation could loose heat (in effect store it converted into some other form) by means of some 'heat sink/converter' the mechanism of which would act as a kind of cosmic temperature regulator and because the nature of this sink is not yet known and therefore taken into account the book keeping won't jibe and there will be problem...<br /><br />but that is only hypothetical, take it as teazer <img src="/images/icons/wink.gif" /><br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[tdamskov]

No problem with being contrarian once in a while <img src="/images/icons/wink.gif" /><br /><br />1. If you take a closer look at the maths behind Olber's Paradox you will notice that although the amount of light is reduced by the square of the distance, so is the angular area of the star. The intensity per area stays constant. Olber's Paradox assumes an infinite amount of stars which means every (EVERY) area of the sky must contain a star. The result? Black body radiation from every point in the sky with a temperature of the surface of a star.<br /><br />2. Finding that interstellar gas has "unknown" properties would contradict current observations that it behaves quite predictably. It IS possible future observations will reveal new particles capable of reproducing red shifting.

 

[alkalin]

Doppler and cosmological, now that is getting rather shifty. Sorry Km but this is a bit too much for me to try to keep on top of the shaky handle. Neither of these occurs if the universe is not expanding per the BB theory. There definitely is Doppler and maybe gravitational shift in the universe, but we can find another effect other than Doppler to explain the red shift we see in the distant universe. That just might be the Wolf effect.<br /><br />If you have a straightforward answer to the combination of Doppler and cosmological shift that can indicate the age of the universe, I would like to hear it.<br /><br />Here is the way I see it: Guth proposed the idea of inflation to put everything where it is because the expansion theory does not explain a very unacceptable situation and so as a theory would have failed. The main expansion theory problem was how could the distant universe be observe way in the past were the supposed big bang occurred, yet we are billions of light years from this event and have been for at least 15 billion years?<br /><br />According to the mystical notion of inflation, everything got where it is today by inflating space, but this had to occur in a very short period of time at near the beginning. Inflation is not supposed to affect matter but space only. After this inflation event, expansion is now the ongoing process and causes the Doppler red shift, so from that alone we can figure out the age of the universe. Well, good luck to you. In order to do so you will need many mystical assumptions.<br />

 

[tdamskov]

<blockquote><font class="small">In reply to:</font><hr /><p>.. but we can find another effect other than Doppler to explain the red shift we see in the distant universe. That just might be the Wolf effect. " <p><hr /></p></p></blockquote><br /><br />Perhaps. I'm not saying the Wolf effect doesn't contribute to the red shifting observed. But reading up on the Wolf effect, it seems to manifests itself only within very narrow parameters. For example it needs coherent light to work, which you generally won't find in nature.

 

[tdamskov]

<blockquote><font class="small">In reply to:</font><hr /><p>Olbers' Paradox might only be a paradox if we would know perfectly how light behaves after having covered a distance of more than 13,5 bio. light years, how exactly gas clouds absorb light, how large Big Holes can get (if they exist), etc.<p><hr /></p></p></blockquote><br /><br />Olber's Paradox is obviously based on the assumption that we <b>do</b> understand how light works. Here's a similar non-argument: We don't understand perfectly how silicon and light interacts, so perhaps some quantum effect in silicon causes redshift? Or... We don't perfectly understand how our brains work; perhaps we emanate a distorting "brainfield" around Earth, which interferes with lightwaves....<br /><br />See how removing all basic assumptions and trust in empirical science opens up the road to mystical non-science? <img src="/images/icons/smile.gif" /><br />

 

[tdamskov]

<font color="red">Stevehw</font> I am often annoyed by the amount of nonsensical and mystical claims in Bonzelite's post. But instead of writing several ranting posts, could you please just ignore him like everyone else? Or at least keep your posts to the thread topic? <img src="/images/icons/wink.gif" /><br />

 

[alkalin]

<font color="yellow">But reading up on the Wolf effect, it seems to manifests itself only within very narrow parameters. For example it needs coherent light to work, which you generally won't find in nature.</font><br /><br />But my understanding is that many sources, especially quasars, are partial-coherent sources?<br /><br />Well anyway, black body reradiates at the temperature of the matter that has absorbed it. This is very well understood in physics and has several associated laws such as Wien and Kirchoff. <br /><br />Yes, how is it possible to see every star in the universe? Even galaxies similar in size and brightness to Andromeda do not appear to our naked eye if they are somewhat further away. This is right there in front of us. Olber’s notions are not valid. <br /><br />Another possible issue you mention is that a stars output is in regard to an area of a stars surface which includes a second inverse square law, but stars are so far from us they only appear as a point source. So only the distance square law would apply.<br /><br />Energy coming from the stars everywhere and being absorbed and reemitted through black body are a very likely source of the CMB. <br />