The size of this universe

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Saint, Jan 14, 2014.

  1. brucep Valued Senior Member

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    Wow. Those numbers are mind boggling. The proton half life is in the 3x10^43 slot. The beginning of the black hole era.
     
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  3. wellwisher Banned Banned

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    I made a point nobody wanted to address because I am right and this is an inconvenient truth. There is no preferred reference. That means that each reference within the universe will see the universe its own way. A black hole will see the universe differently, than the surface of the earth. Most of the analysis of science use the earth reference and act like this is the absolute reference, and ignore that fact that all other references are also valid. Don't you need to average all references to get a more accurate picture.

    The black hole will see the universe as being much smaller and with its time so slow, the universe it will be younger. The size of the universe from this reference is different from what is see from the earth. The smaller universe of the black hole reference, with the same mass will have a universe that will appear much denser with less space-time expansion.

    Dark matter, in our earth reference, is simply an artifact of averaging denser references, like black holes. These see a smaller universe with more gravity due to closer distances. When all such references are averaged in, this appears as dark matter in our reference.
     
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  5. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    "This surface is what is called the last scattering surface." http://ned.ipac.caltech.edu/level5/Glossary/Essay_lss.html

    "The CMB comes from the surface of last scattering of the Universe. When you look into a fog, you are looking at a surface of last scattering. It is a surface defined by all the molecules of water which scattered a photon into your eye. On a foggy day you can see 100 meters, on really foggy days you can see 10 meters. If the fog is so dense you cannot see your hand then the surface of last scattering is less than an arm's length away. Similarly, when you look at the surface of the Sun you are seeing photons last scattered by the hot plasma of the photosphere. The early universe is as hot as the Sun and similarly the early universe has a photosphere (the surface of last scattering) beyond which (in time and space) we cannot see. As its name implies, the surface of last scattering is where the CMB photons were scattered for the last time before arriving in our detectors. The `surface of last screaming' presented in Fig. 9 is a pedagogical analog." http://ned.ipac.caltech.edu/level5/March03/Lineweaver/Lineweaver7_2.html

    "Similarly, looking back in time at the CMB radiation runs into a similar problem. Prior to the "last scattering," matter was so densely packed together that energy couldn't move anywhere in the universe without colliding with matter. We can only see back to about 380,000 years after the initial big bang moment. At this point, the universe had cooled to about 3,000 degrees Kelvin. The microwave radiation prior to this barrier isn't visible to us, because none of it actually made it out of that period. It all collided with other matter! This barrier to our view into the past is often called the "surface of last scattering." " http://physics.about.com/od/astronomy/ig/History-of-the-Universe/CMB-Scattering.htm
     
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  7. paddoboy Valued Senior Member

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    You have made no point at all. Yes all FoR's are valid, so???
    A BH will though see nothing....But if you mean a person who falls into a BH will see the Universe differently, then yes...But again, so??
    He will never be able to communicate what he saw to the outside world anyway.






    Again, a BH will see nothing. But a person falling into a BH, will see the whole Universe squashed into a sphere above his head, before he is torn to shreds and broken down into our most basic fundamentals.




    That is a whole lot of codswallop...
     
  8. brucep Valued Senior Member

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    "pedagogical analog". That's what the 'surface' in surface of last scattering is. A pedagogical analog. "Eventually the Universe cooled to a temperature at which electrons could begin to recombine into atoms, and this had the effect of lowering the rate of scattering. This happened at what is called the recombination era of the thermal history of the Universe. At some point, when recombination was virtually complete, photons ceased to scatter at all and began to propagate freely through the Universe, suffering only the effects of the cosmological redshift. These photons reach present-day observers as the cosmic microwave background radiation (CMB). This radiation appears to come from a spherical surface around the observer such that the radius of the shell is the distance each photon has travelled since it was last scattered at the epoch of recombination. This surface is what is called the last scattering surface."

    Which is a "pedagogical analog" for the lightlike surface of the light cone. Another "pedagogical analog". As Grumpy said there isn't a 'surface'. It's a pedagogical analog associated with events immediately following recombination. They're lots of 'pedagogical analogs' associated with cosmology.
     
  9. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    If you read that website, it was presenting a pedagogical analog of the surface of last scattering for light to a sound that ceases simultaneously, but that you could continue to hear it for awhile if the numerous noise emitters (people shouting) were in a very large room, due to the finite speed of sound. it was, in my estimation, a poor analog. the surface of last scattering is actually a surface from which the photons of the CMB last had contact before thereafter travelling unimpeded to us. the better analog, in my view, is the thick fog one; or the surface of the sun one (to which it is also likened as an analog; including previously in prior threads).
     
  10. Grumpy Curmudgeon of Lucidity Valued Senior Member

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    Walter L. Wagner

    No, it is not a surface. it is a radius in time, there was never any surface that released that radiation. Every point in spacetime released that radiation simultaneously, it was all plasma and then it wasn't because until then the Universe was obeying gas laws, all the matter in the Universe simultaneously underwent a phase change from plasma to normal atoms as we know them. That was the last time that any event happened to the whole Universe at once, prior to that the Universe was one single thing in physical contact with all mass. Up until that moment the Universe was nearly perfectly uniform throughout, a hot dense plasma. After that moment in time it was gas collapsing when the radiation that kept it separate escaped and all that radiation energy separated from the mass. That is the radiation we see 13.7 billion years in our past in all directions. As time goes by we will see that same radiation from other areas further and further away. It is not an actual surface, it is simply the distance at which we see it being released(as it was released right here 13.7 billion years ago). The surface is an illusion.

    The sun has an actual surface of last scattering. But to be like the Universe the sun would have to suddenly become completely transparent to light, where would the surface of last scattering be then? It's radiation pressure would disappear and it would collapse into a White Dwarf if it didn't just detonate and blow itself to pieces. And that's pretty much what happened to some of those galaxy sized gas clouds and the first supermassive black holes formed along with their associated galaxies. We see some of them within just a few hundred million years of the CMB. It may be found that some of those SMBHs may have formed within the late plasma era(BHs eat anything), we may find out soon.

    Grumpy

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  11. wellwisher Banned Banned

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    You are dealing with something analogous to the saying, if a tree falls in the woods and there is no human around to hear it, does it make a sound? The answer is yes, since sound is defined a vibrations that will exist human observer or not. The light we see will become modified differently by the space-time of different references (based on math). I am not concerned if there is a human observer since it does not alter reference or the laws of physics on grand scales like the universe. We may impact the tiniest scales but this will not change the result of the biggest picture.
     
  12. Fraggle Rocker Staff Member

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    This dovetails nicely with current macrocosmology, which tells us that the space-time continuum is only as large as our Hubble volume, on the premise that the space-time continuum is part of the universe, as are the laws of nature as well as arithmetic and logic. This leaves the possibility open that other universes have come into existence, with their own space-time continuums, with such different "natures" that we could not observe them or understand how they operate.

    But previous macrocosmological models postulated the space-time continuum as infinite. If this universe is merely a temporally and spatially local reversal of entropy, as permitted by the Second Law of Thermodynamics, then there may be/have been/will be other universes that popped into existence the same way, elsewhere in this space-time continuum, which has no spatial or temporal limits.

    Bear in mind that mathematics consists entirely of abstractions. This is why its theories can be proven absolutely true, unlike the theories of science which can only be proven true beyond a reasonable doubt, always pending the discovery of new evidence.

    Mathematics uses the concept of infinity as a matter of course; it's a necessity in calculus, for example--not to mention number theory! This doesn't mean that every abstract instance of infinity corresponds to a real infinity in the real universe.

    Uhhh..... I think you're getting ahead of yourself and ahead of the scientific community. To quote Wikipedia--not because Wikipedia is the standard of science, merely because in this particular article it's done a good job of presenting a consensus:

    The Big Bang theory is the prevailing cosmological model for the early development of the Universe. [emphasis added by me]

    The Big Bang has not yet been elevated to the status of a canonical theory. Probably because all the details haven't been worked out yet, but also because 25 years from now, scientists with instruments that haven't been invented yet may discover something that disproves the Big Bang hypothesis.

    Ah! So there is a PaddoGirl.

    "Ignorance" is a touchy word that raises a lot of hackles. Even a faithful adherence to the dictionary definition is guaranteed to make people angry when it's applied to them.

    And indeed it is commonly used hyperbolically as an insult, like "moron," "idiot,""retard," etc. It's best to choose a different, less offensive word, rather than spending the next three days explaining what you really meant.

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    If I understand the current model (a big "if"), the "universe" is nothing more or less than "everything there is." So if you build a rocket fast enough to travel to the boundary of the universe ("edge" implies that it is flat, and one of the few things we know for sure about the universe is that it is not flat

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    ) during a single lifetime, and then poke your little rocket nose through that boundary, what you have done is merely increase the size of the universe. You're still inside it.

    Again, will you guys please damp down the personal insults. Phrase your complaints in such a way that you're talking about the topic, or at least the points of view on the topic... not about the people.

    This is a long discussion that gets a lot of posts every day. I find it very difficult to keep up with, so I have surely missed some of the points you and others have made. If I don't respond to them, it doesn't mean that you're right, I'm wrong, and you have discovered an "inconvenient truth."

    It merely means that we all have a finite amount of time and energy to devote to SciForums, so we can't read and answer everything that's posted.
     
  13. Grumpy Curmudgeon of Lucidity Valued Senior Member

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    Fraggle Rocker

    I have mentioned these things in previous posts but made the point then that we just don't know(and likely never will)anything about conditions outside of our Universe. The Universe had a beginning, it had a source, it's just that all information about those things is destroyed or scattered by the BB singularity and cannot be sensed on this side. But any speculation about any characteristics of the "Metaverse" is not based on any evidence, we do not know that it is infinite, for instance. I doubt that it is, it too may be finite and have a source, as that source has it's own, etc. ("Turtles all the way down")and the only real infinity is the number of sources, if that.(yes, I know I have a problem when it comes to "infinity", but it is a word and concept that gets thrown around and misapplied constantly but is never actually observed in Nature. It's important to use words and concepts precisely or not to use them at all.)

    Like I said before, why posit infinity when everything we know about Nature tells us they do not and cannot exist? I don't know, but it seems to be presumptuous. I agree that our Universe is more likely NOT to be all of existence(though it is all of OUR existence). We don't know what spatial or temporal limits there might be there, but my bet would be on there being such limits. Given the instant of Inflation here at the very first moment in time it might be a hint that those limits are set at very high values of density, temperature and speed, but not infinite ones.

    Yes, infinity means different things to different reference frames. You have outlined what it means in math, it actually exists there, but math is a completely artificial "reality" of rules and premises, not the real world.

    In science infinity has a very precise definition and a rigorous requirement to not use infinity when you mean "very large number" or "continuing into the future forever", etc., which is the meaning laymen use. It's a similar situation to the meaning of Theory, which means "guess" to a layman and "confirmed provisional explanation supported by the evidence" to a scientists. A "hypothesis" is the scientific term for "informed speculation" or "provisional explanation not yet confirmed by evidence", even that is still above the quality that laymen give the word "theory". When Buzz Lightyear used the phrase "To infinity and beyond!" in Toy Story I cringed, it bothers me that much. I need professional help.:facepalm:

    Grumpy

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  14. Fraggle Rocker Staff Member

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    Considering everything we learned in the 20th century, it seems foolish to presume that there is a specific area of knowledge that we'll never plumb. To say that we won't ever know everything, well okay. "Everything" is probably infinite. But that doesn't tell us which things we will be able to figure out and which we won't.

    The fact that we can't observe it doesn't mean that it's not out there. The currently fashionable version of the Big Bang model (with a finite universe) has not been proven true beyond a reasonable doubt, which explains why it's only a model and not a canonical theory.

    Don't try to get away with that assertion on the Linguistics board! Language is one of many arenas of human activity in which "doing the best we can" is the rule. Words, in particular, simply don't have the "precision" you long for. Their meanings change subtly and constantly.

    You're still hung up on the glittering new cosmology, in which f=ma, 1+1=2, nothing can travel faster than light, if all A's are B's and all B's are C's then all A's are C's, and the familiar space-time continuum with one temporal and three physical dimensions, are characteristics of the space-time within our own Hubble volume. You know that could turn out to be wrong, don't you?

    We absolutely do not "know" that there's no such thing as infinity.

    You just conceded that there could easily be something beyond our Hubble volume--assuming that the word "beyond" means something in this context. What makes you so sure then, that there are not an infinite number of things out there? Your allergy to infinity could use some medication.

    Please present the evidence and logic that supports your bet.

    In our universe, perhaps. But what if our universe is simply a tiny part of something larger? What information or reasoning do we have to suggest that "larger" cannot be "infinite"?

    I'm really curious as to why your world-view (universe-view? cosmos-view?) is so constrained. Humans are famous for having imagination with no limits. I guess it's that allergy.

    Huh??? Last time I had a plate with one doughnut on it, and put one more doughnut on it, I counted very carefully and was quite certain that I ended up with two doughnuts. Naturally, after this amazing observation, I was determined to attempt subtraction. And after removing the two doughnuts and placing them in my stomach, sure enough, the plate contained exactly zero doughnuts.

    Every time I apply the "artificial reality of rules and premises" of mathematics to the real world of bosons, leptons and quarks, I discover that those rules and premises are just as valid here. What planet do you live on, where you have a different experience?

    Our great-great- to the thousandth power grandparents invented arithmetic specifically because it was useful in dealing with the counting and manipulation of actual real objects. It was not an "artificial reality" to them--nobody was trying to build a Klein's Bottle out of reeds and mammoth tusks. On the contrary, it was a real reality. (Since language was most probably invented around 70,000 years ago, I took the liberty of assuming that arithmetic is somewhat younger.)

    I bet you don't get invited to a lot of parties. As a linguist and a once-upon-a-time math major, I thought that was hilarious.

    You need to spend a couple of months with Beaker and Dr. Honeydew in the Muppet Labs.
     
  15. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Well, your semantic useage differs from the majority, such as the web-cites I referenced discussing the "radius in time" as being the 'surface' of a spherical shell at that radius (12.7 billion lightyears or thereabouts). Agreed, within each reference frame, the decoupling (last-scattering) took place relatively simultaneously. But because we are not in the other reference frames simultaneously, but rather in our own reference frame of the Milky Way, we see the decoupling of only a small portion of that matter, that portion which is now, in our Milky Way reference frame, at a radius of about 12.7 billion light years away. That is what the WMAP shows, those photons that have travelled 12.7 billion light-years at c. And it shows that the Milky Way is moving, relative to that background spherical radius (which most writers describe as a 'surface', at a high rate of speed, leading to the dipole anisotropy I've written about before. http://www.astro.ucla.edu/~wright/CMB-dipole-history.html http://apod.nasa.gov/apod/ap010128.html
     
  16. Boris2 Valued Senior Member

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    what you're saying is that our theory of relativity, GR, would be different if we lived on a far higher gravity world? i don't think so. if we went through the same scientific processes there as we have on earth then our conclusions about the universe would be the same. after all we can theorise what the universe would be like if we did live on a higher gravity world and theorise what the universe would look like from there so why not vice versa?
     
  17. brucep Valued Senior Member

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    You're trying to make it impossible to acknowledge nonsense trolling for what it is. Trolling nonsense in these threads. You can't say it's ignorant nonsense without hurting the trolls feelings. What about how we feel about the bullshit that gets thrown in the face of every thread. It's not kindergarden. Find one post wellwhisher has made that isn't bullshit nonsense? You moderators need to figure out what constitutes trolling these threads and do something about it. It's getting pretty bad. Whoever is moderating the science threads needs to do some work.
     
  18. Boris2 Valued Senior Member

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    i agree. i haven't seen anything in this thread that could be construed as a personal attack, and if there has been then it is mild. people posts have been called ignorant. compared to what has happened elsewhere on these boards i think some consistency policy needs to be thought out by the mods.
     
  19. paddoboy Valued Senior Member

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    I do tend to agree....
    Once again, in another forum I was partaking in [no not that one Boris] they have a specific alternative theory section, and anyone with an alternative theory have one month to supply evidence that invalidates the incumbent theory, and/or describes the subject in question better.
    If they fail to do this, the thread is closed.
     
  20. paddoboy Valued Senior Member

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    The problem here as I see it, alternative theorists and their ilk, are doing their damdest to put their theories into mainstream science sections, and wellwisher appears to be a master at that game.
     
  21. paddoboy Valued Senior Member

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    As an example Beaconator has succeeded in doing that in physics and maths under "Possibility of star formation around black holes" thread
     
  22. wellwisher Banned Banned

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    Depending on your frame of reference will have an impact in what you see. The earth only provides one reference. If we model from the earth, unless this is the absolute reference of the middle ages, this is only one of many.

    Relative to observational reference, earth reference did not exist at the BB and for some time thereafter. The early universe average reference was much different that it is in the present. The dark matter and dark energy where more visible.
     
  23. Grumpy Curmudgeon of Lucidity Valued Senior Member

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    Fraggle Rocker

    In this sentence I agreed with what you said until the last seven words. YOU have no evidence conditions on the other side of the singularity have no spatial or temporal limits. I have never claimed to KNOW that infinities do not exist, but once a few hundred years of no sightings having occurred one should not invest in unicorn hunts. No evidenced candidate for an actual, physical(not conceptual)infinity has ever been shown. I would not posit one sans extraordinary evidence anymore than I would posit that UFOs are alien spacecraft. I have an aversion to infinities being offered, as I do for the Alien spacecraft explanation of lights in the sky. No, one cannot say that infinities are impossible, that's why I just say they have never been seen, that the evidence of Nature seems to preclude their existence, just like alien spacecraft. In science , if your calculations lead to an infinity, you need to go back and look again, because they are never seen in reality(so far). Even the one type of candidate where infinities are postulated for (BHs)are just speculation at this point, it occurs on the other side of the event horizon and is technically outside of the Universe. Even there Quantum effects come along and disrupt the singularity(we think).

    Actually, the expansion of the Universe is undeniable. At some point in the past there was a much smaller and denser Universe, and a way to stop from coming to some form of Big Bang theory is hard to see, logically. And then there's the direct evidence. We don't know everything, probably never will, but Relativity and the Hubble expansion are clues leading to something that is going to come out looking like current theory. It's like Darwin and the modern synthesis, we may write a few more verses, but Hubble wrote the tune long ago.

    They do if used correctly, something I try to do at all times. A scientist needs to precisely define the terms he uses in his logic and the way a scientist defines theory, spacetime, infinity and many other terms is precise. It isn't the only definition, it is the only scientific definition. In most cases the scientific definition is the same in math, infinity is an exception, it is accepted as real and can be used in equations, that is not true in science. Get back to me on that if you ever find a real infinity.

    But it was what we learned in the 20th century that showed us some of those limits. A simple one is that we will never see most of the present Universe. We will never know a thing about the other side of the BB, we will never see a naked singularity, we will never travel at or above lightspeed. There are lots of limits we will never exceed. But that in no way limits our ability to learn and finding a limit in one direction allows you to expend your energy in others. We will probably never be able to fly in Earth's atmosphere with flapping wings like the birds do(a physical limit imposed on you by the Universe), but that don't mean we can't fly.

    You mean the current best understanding we have given current evidence? I suppose unicorns will finally be found, but the evidence leads to not putting a lot of energy into the hunt. So far, the evidence supports the current synthesis, new information or understanding may modify it, but it doesn't seem likely to all turn out to be false.

    .

    Like we do not "know" anything at all. If no valid instances have ever been found the likelihood keeps going down. Currently infinity occupies the same level of credibility as unicorns, alien spacecraft and vampires, none have ever been seen(though many have been claimed). I know infinity is a serious question(unlike the other three)but the same rules of evidence apply.

    When it comes to things outside of our Universe, no one knows anything, including you or I. But everything we see within our Universe is finite, we've never seen anything matching the scientific definition of infinity. Why posit an infinity? The evidence suggest that no such thing exists. Why posit it for a situation you have absolutely no information about? I need no medication, it seems mine is the more logical position, we've never seen one, why invent it?(except as it is useful in math, that is. A zero has never been counted either, but math has one anyway)

    The fact that no infinity has ever been found outside of the mind of man. If no infinities here, none expected there unless and until contradictory evidence is presented. I don't know what the hole card is, but if we've been playing all night and no Joker has been played yet, I doubt the hole card is a Joker and would bet as if it was not a Joker. This is really simple logic, you know. I could turn out to be wrong, but the odds are with me.

    Not "cannot' but not in evidence. Why posit something never seen here existing at all? What if the other side of the BB singularity is a single mustard seed in another Universe? We can imagine a lot of things, but that does no mean they are real.

    As a teen I loved Star Trek, I used to dream about visiting alien worlds. Then I learned just how limiting physical reality is. Now I don't think of travel between stars as being on an interstellar airplane for a few hours, or an interstellar ship taking a few years, I think of travel to another star as being a desperate, centuries long, multi-generational trip requiring most of the resources of a solar system to escape our dying solar system because that is the only thing that could or would force such a trip. Once you start gaining knowledge you may have to change your view of the world. Some don't, they reject reality in favor of their beliefs, I do change my world view, even though I miss that naivety and childhood flights to other planets in my mind. And my allergy to woo is a result of that lifelong learning, not a hindrance to it. All my life I've heard "infinite this" and "infinite that", but on looking in to it it turns out that throwing "infinite" into your work means your work is probably wrong and you don't understand something or everything about which you are talking. Without a single verified instance of any infinity the logical position is not to posit them until valid evidence of their existence is found. That is the current state of infinity, so the question becomes why are you so free with an unevidenced concept? How about a little rigor here?

    Grumpy

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