Astronomy Without A Telescope – Our Inferred Universe

Article written: 2 Apr , 2011
Updated: 24 Dec , 2015
by

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The universe is a big place – and getting bigger all the time – so at a large scale all unbound structures are all moving away from each other. So when we look out at distant objects, we need to remind ourselves that not only are we seeing them as they appeared in the past, when the light that hits our eyes first left them, but also that they are no longer in that location where they appear to be.

This issue reaches an extreme when we consider observations of the first luminous stars and galaxies – with the galaxy UDFy-38135539 currently holding the record as the most distant object observed and one of the youngest, existing 13.1 billion years ago – although UDFj-39546284 may be the next contender at 13.2 billion years old, subject to further spectroscopic confirmation.

UDFy-38135539 has a redshift (z) of 10 and provides no measurable light at visible wavelengths. Although light from it took 13.1 billion years ago to reach us – it is not correct to say that it is 13.1 billion light years away. In that intervening period, both it and us have moved further away from each other.

So not only is it now further away than it appears, but when the light that we see now was first emitted, it and the location that we now occupy were much closer together than 13.1 billion light years. For this reason it appears larger, but much dimmer than it would appear in a static universe – where it might genuinely be 13.1 billion light years away.

So we need to clarify UDFy-38135539’s distance as a comoving distance (calculated from its apparent distance and the assumed expansion rate of the universe). This calculation would represent the proper distance between us and it – as if a tape measure could be right now instantaneously laid down between us and it.

This distance works out to be about 30 billion light years. But we are just guessing that UDFy-38135539 is still there – more likely it has merged with other young galaxies – perhaps becoming part of a huge spiral galaxy similar to our own Milky Way, which itself contains stars that are over 13 billion years old.

The observable - or inferred - universe. Even this may just be a small component of the whole ball game. At this scale, our immediate galactic neighborhood, the Virgo Supercluster, is too small to be seen. And it is extremely unlikely that it represents the center of the universe. Credit: Azcolvin429.

It is generally said that the comoving distance to the particles that emitted the cosmic microwave background is about 45.7 billion light years away – even though the photons those particles emitted have only been traveling for almost 13.7 billion years. Similarly, by inference, the absolute edge of the observable universe is 46.6 billion light years away.

However, you can’t conclude that this is the actual size of the universe – nor should you conclude that the cosmic microwave background has a distant origin. Your coffee cup may contain particles that originally emitted the cosmic microwave background – and the photons they emitted may be 45.7 billion light years away now – perhaps just now being collected by alien astronomers who will hence have their own 46.6 billion light year radius universe to infer – most of which they can’t directly observe either.

All universal residents have to infer the scale of the universe from the age of the photons that come to us and the other information that they carry. And this will always be historical information.

From Earth we can’t expect to ever come to know about anything that is happening right now in objects that are more distant than a comoving distance of around 16 billion light years, being the cosmic event horizon (equivalent to a redshift of around z = 1.8).

This is because those objects are right now receding from us at faster than the speed of light, even though we may continue receiving updated historical data about them for many billion of years to come – until they become so redshifted as to appear to wink out of existence.

Further reading: Davis and Lineweaver. Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the universe.



53 Responses

  1. wjwbudro says

    “Your coffee cup may contain particles that originally emitted the cosmic microwave background – and the photons they emitted may be 45.7 billion light years away now -”
    I’m going out on a limb here and read something into this…
    So, the photons that are emitted by the particles that make up my can of beer (and the beer that was within) are those that didn’t escape re-ionization?
    Conservation of energy rules!
    Photons!, never say die!

    • Member

      A CMB photon has to escape a lot of things to reach your eye 13.7by later.

      Not sure what you mean by ‘those that didn’t escape re-ionization.’ As I understand it, reionization (i.e. splitting stable atoms back into ions and electrons) was largely driven by photons produced by the first stars.

      I am reminded of Yahoo Serious (Young Einstein) splitting the first beer atom 🙂

  2. Lawrence B. Crowell says

    Quote: Similarly, by inference, the absolute edge of the observable universe is 46.6 billion light years away. I must stress that this is the limit to optical observability to the universe. If we do gravity wave and neutrino astronomy we should be able to peer much further out to much closer to or into the inflationary period.

    UDFy-38135539 with z = 10 is currently, which is time defined on the spatial Hubble frame, about 130 billion light years out. That galaxy is in a mature state of development comparable to galaxies we see within 100 million light years from us. There may be intelligent life on some planet there looking out and detecting the progenitors of the Virgo galaxies or our own local cluster. This might be happening right now according to time defined on the Hubble frame.

    The atoms which make up everything around us was up to 380,000 years into the big bang hydrogen and helium in a hot plasma that absorbed and re-emitted photons. Going further back in time up to the first 3 minutes of the universe the atoms around us are just a residue from a hot gas of particles and anti-partilces, where parity violations gave this excess matter over anti-matter at lower energy. Prior to that up to 3 seconds into the big bang you had electroweak unification and broken or partial supersymmetry, prior to that GUTs and supersymmetry in inflation, earlier still quantum gravity and strings and … .

    I will propose something, just to outrage people some. Feynman’s idea of the path integral is that a particle would traverse everywhere, and back in time to cover the entire universe. This was not a tractable thing to work out, so we have this approximate idea of the path integral. If you follow Ed Witten’s work you might be aware of some generalizations of this. The heterotic group E_8 has 248 roots in an irreducible representation. The supersymmetric E_8xE_8 which is isomorphic to SO(32) has 496 element or roots. These represent elementary particles. In a grand partition theory of states or path integral of the universe these are then the only particles that exist, one up quark with color indices, one electron, one photon, one e-neutrino, one … . The electrons which are pushing their way through circuits in your computer are just entanglements of one electron with separate configuration space representations. The same holds for photons, and quarks and … . So that electron pushing through a NAND gate in your computer is the same electron as an electron generating a current in an accretion disk around a black hole, which is the same as all the others. They are all entanglement states with different configuration variables of the same particle state. If you think about it this is rather bizarre.

    LC

    • wjwbudro says

      Damn, my head hurts!

    • Mr Mike says

      LC -> “They are all entanglement states with different configuration variables of the same particle state. If you think about it this is rather bizarre.”

      I agree with Richard “Time is not a measure for the basic particle” I think I got that one right but if not well, my memory is faulty — and now to paraphrase the rest of the statement of conditions he imposed for that thought — if memory serves me today, “certain conditions seemingly grant us a view of these particles, a limited view, which implies duration for the particle which does not seem to be a basic property for any particle.”

      I liked this idea when first I hear it and embrace it still to this day. Thank you for restating this ancient origination of the path integral by Feynman – with Dirac quantum action being the original placeholder.

      If the electrons are not all entangled in this fashion then the universe I see with my minds eye is slightly out of focus. This entanglement extends to any thing we can see and a lot we can not see but know exist as well as those items which have passed our (present) ability to detect (but may be detectable at sometime in the future, in other words.)

      Classical action principles puzzle most all who study them because of their seemingly teleological quality. Us lay-folks find this to be a matter of the utmost importance since it would seem –given a set of initial and final conditions — one is able to find the only unique path connecting them. It is as if the system somehow knows where it’s going to end up and how it’s going to get there.

      With path integral formulations we can see why this works –in terms of quantum superposition being a part of if not the whole of the solution. Every possible path to any possible endpoint works because known interference effects guarantee that only the contributions from the “stationary points” of the action give “histories” with appreciable probabilities.
      Mike C

      • Lawrence B. Crowell says

        Saint Rich got a lot of things right. His original insight into the path integral always intrigued me, and I always found the narrow formulation of path integrals to be a far cry from his original “vision” of things. Last fall I was reading a paper by Ed Witten on path integrals, where the vertex topology of string makes path integrals more sensible. I was struck by how Ed’s paper seemed to march in the direction of Feynman’s idea.

        If you follow some of my posts on these astronomy w/o a telescope and Cosmology 101 blog entries you might see where I have talked about finding the eigenstates of the universe. This is in part what I am referring to, where the particle eigenstates are given by these groups, and the entanglements with respect to configuration variables are governed by the Hartle-Hawking states. The HH-states turn out to be due to a duality between the anti-de Sitter space in two dimensions and a field theory on the boundary in one dimension. This gets a whole lot deeper involving partition of states on horizons and some number theory proofs recently accomplished.

        LC

      • Question says

        lawrence,

        as i read this article, i found myself thinking of some of the things you have recently written in other threads. it was most helpful.

        …your comment was helpful too mr.mike.

        thanks!

      • Lawrence B. Crowell says

        The article by Davis and Lineweaver covers a lot more ground than what I write about. The one point in their article which I have a bit of a question about is their distinction between the Hubble sphere and the horizon. This comes about because our universe is not a pure de Sitter spacetime, but has this messy perturbation of matter and radiation. This played a more dominant role in the past, but it is becoming weaker with time. The existence of matter and radiation is the reason the horizon deviates from the Hubble sphere. However, if you look at the diagrams in the paper you see that the horizon and Hubble sphere converge in the future, and in both time and conformal time.

        Conformal time is an issue I have avoided discussing here, for that is bound to cause confusion. However, this paper gives some indication of that.

        The other oddity is the definition of the horizon as the distance light can travel from a time t to a time t = infinity. This is the distance one can send a signal to, where any object inside the c = Hd limit, with distance d = H/c, can receive a signal or light ray we send to it. However, by the time that light ray reaches a receiver, it will have receded out to a far greater distance than d = H/c. We can see any object beyond the horizon d = H/c, but we can never send a signal to them, nor can they send a signal to us from a time on the Hubble frame. We can only see them as they are in the past, but not the present or the future, and any observer there can never know about us in our present state.

        The particle horizon is the limit for “infinite redshift.” The CMB occurs at z ~ 1000, and the particle horizon is the case where z ~ 10^{57}, where infinity is restricted by the Planck length and the size of the CMB radius. In other words this limit indicates how a Planck scale or superstring scale quantum can influence the structure of the CMB. B-modes of gravity waves are such a prospect. The particle horizon is vast, and it does indicate how we can learn a whole lot about the observable universe, far beyond the CMB radius.

        LC

      • Mr Mike says

        Thank you Question.

        Some thoughts on what integral paths would mean in everyday life.

        If all particles are the entangled state of their basic particle; all are derivable from the FPP (future/past/present) of that dumb particle. Yes, dumb, otherwise the particle we analyze would potentially provide intellectively comprehensible data –which condition is contrary to our current understanding of the cosmos via GR. These particle eigenstates are given entanglements with respect to configuration variables we would see as being granted via FPP if we could but see into that condition.

        Those pesky perturbations of matter and radiation and the resultant impressions of duration we experience can be all too true with the concurrent “original” path integral; however, integration vs segregation is not a consideration when duration is subtracted. The tangled web is there, where we perceive it to be, in our slice of duration — but the path to ‘this’ place for any part of that tangle has eluded our perception — because we experience duration in one ‘forward’ direction, rather than as unity. If we segregate what is integral a path can not be perceived.

        The fuzziness of the cosmos as show in these thoughts may well exist in actuality at lengths greater than the Planck length, the QM foam may provide a head to the beery glass as it were, rather than be un-notable to us on this macro level as we posit. The cosmos may well have a backbeat we can use .

        Mike C

    • Torbjorn Larsson OM says

      I’m not sure why it should be outrageous, unless you think mathematical presentations must represent reality. But then you have bigger beef to stew. (Tegmark’s ultimate ensemble multiverse for one.)

      A time tested variant was that anti-particles were particles that travel towards the past. In a similar vein here we have entanglements not with actual particles (or fields) but with their representations.

      An analogy would be the model that there is only one rotation, so every particle or particle assembly participates in it (or not) irrespective of their individual position and spin orientation.

      But each and every instance is real, so responds with a unique reaction to every action (observation). Or in other words, rotation or entanglement doesn’t work that way, or at least hasn’t been observed to do as of yet AFAIK. (Theoretically I guess you could say that the parsimony of the idealized representation is sunk by its unparsimonious actual representation.)

      • Lawrence B. Crowell says

        Tegmark’s proposal is “way out there,” and so far out that I am not clear that it can ever have any bearing on science as an observational or experimental science.

        The prospect that the universe only contains one electron, and one of each elementary particle, but where each exists in an entanglement of configuration variables could in principle be tested in black hole physics.

        LC

      • Torbjorn Larsson OM says

        I accept that distinction, good catch!

        However, it seems we will have to agree to disagree on that one. My reasons as per my previous comment, I can’t see how the observed nature of entanglement isn’t already constraining such physics.

    • snm359 says

      Lawrence, I have been a long time lurker on this site and I have never felt the need to respond previously but I had to comment on what you’ve put here, I think its just a typo but no one else as pointed it out, “130 billion light years out”. If this is in fact the case I have some serious reading to catch up on, please point me in the right direction. By the way I really enjoy reading your views, you have given me a great deal to think about.

      • Lawrence B. Crowell says

        This has been something I have explained a number of times. The paper referenced above discusses this as well. It sounds strange that a galaxy might be almost time times outwards than the distance of 13.7 billion light years in time as the age of the universe. However, space itself is expanding. Point in space are moving apart from each other, and they move apart at a rate proportional to their distance of separation. Space can dynamically evolve in such a way that particles on the space can be frame dragged to arbitary velocities. In this way an observer who falls into a black hole exits this observable universe faster than light, for space itself if “flowing inwards.”

        LC

  3. wjwbudro says

    Weren’t there two re-ionization periods?
    http://www.universetoday.com/75234/hubble-helium-reionization-was-a-hot-time-in-the-ol-universe/
    I was referring to the first, following the dark ages after the inflation era before the first stars when the soup was cooling and aggregating.
    I’m sorry I keep beating this drum but you all keep pinging my interest every time UT reports a new discovery.

    • wjwbudro says

      Sorry LC, this should have been posted as a reply to Steve.

    • Member

      Yes. I had assumed you meant the first. But it is driven by photons from new stars/objects forming after the dark ages, see:
      http://en.wikipedia.org/wiki/Reionization

      The formation of these luminous objects (stars etc) is what brought the dark ages to a close.

    • Lawrence B. Crowell says

      After the first PopIII stars ignited they threw off lots of X-rays and UV that ionized a lot of the gas in the universe.

      LC

    • wjwbudro says

      Again Thanks Steve and LC., sorry this is late and thanks for the link. I have read it before as well as a number of other differing explanations. That is why I am fishing here and hopefully not wasting any ones time.

      “The formation of these luminous objects (stars etc) is what brought the dark ages to a close.”

      Yes, I know but, these early stars/object weren’t the source of the CMB, or, because of their stretched distance, they are the “later and a tad hotter” part of the source? IOW the CMB is time/distance event layered so to speak; it started out smooth and isotropic and later the matter phase created the nooks and crannies anisotropies. Sorry my questions may be poorly worded and I won’t be offended if I don’t get a reply. lol

      • wjwbudro says

        Sorry, if I see my Q’s vague, you must.
        By matter phase I meant the stars/objects following; did some of the photons produced by the hot early POP III stars escape re-absorption and become the part of the CMB surface?
        I really appreciate your patience and I’ll keep researching, i promise, lol

      • Lawrence B. Crowell says

        The CMB surface is in the past. Photons generated subsequent to that propagate into the future. The PopIII stars pumped out lots of UV and X-rays into space, which was much denser then than intergalactic space is now, and these photons ionized neutral atoms.

        LC

      • wjwbudro says

        Your making me work hard LC, I wished I had a better grasp of science speak. lol
        I hope the folks here don’t mind but I will try and compose my question a better way and post later. lol.

  4. Manu says

    Highly interesting paper that you linked, thanks Steve!

    I was not aware of the ‘supernovae time dilation’ studies ruling out no-expansion redshift explanations. This is a very important confirmation for the Big Bang model(s)!

  5. Split_Infinity says

    Can we ever look back far enough to actually see to the point where galaxies don’t exist, that would be conclusive proof of theories, but from what I gather it is just out of reach? I have a feeling we’re being trolled, the proverbial carrot on the stick.

  6. Torbjorn Larsson OM says

    Nice article, makes you think and feel at the same time.

    The way to remember the gist may be: as cosmological redshift acts, sooner or later our observations will tend towards infer-red.

    … no, no, that is all right, I can take my coat and leave now. (\_/)

  7. “…..when the light that we see now was first emitted, it and the location that we now occupy were much closer together than 13.1 billion light years. For this reason it appears larger, but much dimmer than it would appear in a static universe……. ”

    I believe this explanation is logically invalid. Regardless of how close our galaxy and UDFy-38135539 were together at the time the light that we are observing now was first emitted, the light supposedly has traveled 13.1 billion light years in the interim to reach us. The effect should be consistent with this distance even though the galaxy accordingly would be farther away now or closer then. The galaxy should appear as red as the appropriate redshift for that distance and should have a brightness according to the inverse square law according to the BB model. I also believe that if the valid interpretations of observations differ from this then there is a different explanation for the galaxy appearing larger and/ or dimmer than it should. If this “larger” appearance is valid alone then I think that the correct explanation for this observation could overturn the standard model by itself.

    • Hon. Salacious B. Crumb says

      “….could overturn the standard model by itself.”

      Sigh¡

      • Lawrence B. Crowell says

        My sentiments exactly. I am not sure what to do. I can’t write endlessly about this.

        Everyone who is a layman on these topics who reads a popular book on them, and then thinks they have found a flaw in modern physics and an idea of how to fix it should do a mental halt! You are 99.999% certain to be wrong about this. People should not assume they are some budding Einstein after they read a book by Carroll or Randall or others.

        LC

  8. @Lawrence B. Crowell,

    For more than 50 years I have believed the BB to be the wrong cosmological model; the alternative theory that I adhere to is my own model. It’s called the Pan Theory and can be found by using any search engine. Whether or not my model is the correct model/ answer, I think you will find that the BB model will continue to be contradicted by very old, large appearing galaxies at the greatest distances and that the Big Bang model will be replaced, probably in no more than a few decades. The subject galaxy/ observation is just another in a great number of examples.

    • Hon. Salacious B. Crumb says

      Peter Pan : “I do believe in fairies. I do. I do”
      Sprinkle a bit more fairy dust… here, and here and over there.
      Whack job, more likely.

    • Hon. Salacious B. Crumb says

      “Whether or not my model…”
      Are you in the fashion industry?
      Hope she’s pretty.

    • Hon. Salacious B. Crumb says

      According to your “Pan Theory” or your written work “The Pan and Ipan Theories A Wholly Unified Model of Cosmology and Physics” (a personal theory if I’ve ever heard of one), “The galactic red-shift: is not an expansion of space or a Doppler-shift.” Eh? You are kidding aren’t you?

      Your Pan Theory is truly hilarious! Wow, you even profess and have the audacity of your own version of Relativity!!!

  9. danthony930 says

    I disagree with the universe diagram. I do not believe that the Virgo Cluster (Milky Way) is in the center of the universe. I would think it is more likely that we are closer to one side thereby being farther from the other.

    The above diagram could lead many to think that we are the center point of The Big Bang.

    • Hon. Salacious B. Crumb says

      …but we are the centre point of the Big Bang, and by all accounts it is in a house that is painted white in Washington D.C. (or at least rumour has it.)

      akljgkowkrg fkopakf;k ;l;k’o kk ‘k’gk;wf makes far more sense.

      Thank you for your brilliant insight. Ta¡

      • Hon. Salacious B. Crumb says

        Probably a bit cruel. The answer is of course that the universe is expanding at the same rate from the point of view of other galaxies in the universe too. I.e. If the universe is 13.7 billion years old or so, therefore, every other galaxy in the universe sees the same age. There is no favoured geocentric centre in the entire universe from any galaxy. (except for my earlier comment, and that IS debatable!)
        [If you know this and still believe your words are true, then shame on you! ]

    • Uncle Fred says

      No geocentric center. The diagram is purely illustrative regarding how the Universe appears from our perspective. Pick any point in space on that diagram and the viewer will have the same perspective (.e. they too will have a diagram like the one above). This is called the Cosmological Principle. We know from observations that show the universe is both homogeneous and isotropic.

      • Torbjorn Larsson OM says

        Another version, stronger since less assumptions, is to notice that it is a depiction of _our_ observable universe. Other observers will have _theirs_.

        On your more qualified and informative version, it is noteworthy that the old principle as first stated by Newton, a first and good to boot assumption, is now transformed. I believe he would have called it a law as per the standard cosmology that embodies it.

        [Of course both the law and the cosmology are very recent and still put to many tests, especially the former as described in a UT post last week.]

        Undoubtedly we will continue to call it “principle” in the same way that “law” has lost some of its original glamor. It is all in theory, if not “a theory”, nowadays. I wonder what an old observer like Newton would have said about that.

  10. Hon. Salacious B. Crumb says

    I have resisted to make any comment, at last until the nutters like Peter Pan turned up! It seems to have taken a while before the conversation descended into hell this time. Needless to say, I enjoyed very much the discourse here, and have little to add except that I have appreciate for the considered comments. Sometimes you can learn much about cosmology by watching. Thanx.

    • Uncle Fred says

      My sentiments exactly. I read nearly every article, and do a hell of a lot more listening then commenting. I’m still on my training wheels here (more like my training wheels have training wheels) so often I have nothing worth adding – usually just questions.

      Thanks goes out to those who input their expertise. As for Forest Noble and droves of others, If you don’t agree, it’s likely you don’t understand something. Ask questions! People here are generally helpful (yes even Salacious). It’s the I’m right and you’re wrong, here’s my personal theory that irks the heck out of our resident experts.

      Cosmology is not an easy or intuitive subject. As LC wisely stated, you are 99.999% likely to just not understand something. Please don’t make up personal theories!

  11. Lawrence B. Crowell says

    There is a common misperception that spacetime singularities are points. In Euclidean spaces this is the case. Euclidean space has a distance d^2 = x^2 + y^2 + … +z^2, which is just a form of the Pythagoras theorem in n-dimensions. Spacetime is pseudo-Euclidean and has a distance s^2 = -(ct)^2 + x^2 + y^2 + … +z^2. This has a number of profound consequences, some of which are not entirely understood. However, it is a general conclusion that singularities are not points in space, but a space with a large curvature in the past for future. Singularities are associated with changes in space with time, what we call a diffeomorphism, and with black holes points of space slide into the black hole, and with cosmologies points slide apart from each other. However, the singularity is not a point,

    This confusion with singularity and points is a part of why people think there must be a center to the cosmological spacetime. The diagram which places the Virgo cluster at the center is just a coordinate choice. The Virgo cluster, being about 15.5Mpc or 50.5 million ly away, is for practical purposes in our cosmic black yard. So our coordinate origin is then centered in the Milky Way galaxy, which is on cosmological distance scales practically in the Virgo cluster. Now on the Hubble frame, observers a billion light years out will put the coordinate origin on their galaxy. Where that central point is placed is due to a coordinate choice, which is permitted freely in spacetime physics. This coordinate origin has neither anything to do with the spacetime singularity of the big bang, nor a center to the universe.

    Singularities in spacetime are in a more general setting quantum gravity processes, or Dp-brane or M-theory transformations, and so forth. The singularity is due to the incompleteness of classical description of physics and spacetime.

    LC

  12. damian says

    Well if you ask me the universe exists in a jar of Nuttella. Pffttt. 🙂 Full of entertaining nutty goodness. Even goes with popcorn when reading comments. !

    It is a fascinating subject. Thanks Steve. Hat off to informed discussion following too. Makes me wonder what the Universe looks like right at this very moment. It almost seems cruel to realize that we are trapped in one frame of time.

    Stares into jar of Nuttella….. Muses on the purpose of entropy again. 🙂

    • Mr Mike says

      Now damian, I must take exception to your use of a person choice of universes in your post. If you call dibbs on nuttella then hundreds of others will want to use their favorite butter or jelly, spread or sauce… any of thousands of countless items to describe their views as opposed to the ‘correct’ view, err, mine I mean.

      The universe exists because of the nut, because of the jelly. They called out to the past and were granted fulfillment in the due course of time leading to what we see around us. It all exists for that singular purpose or cause, the expansion of jellies and butters — since nature abhors a naked bit of toast. I know this because me mum told that to me and she never lied while she lived, or at least I never caught her in a lie before she died, what she is doing now in death is anyone’s guess, I guess.

      Yes, toast & crumpets, and maybe some other delectables (I have yet to finish my experiments which would diffidently prove something one way or the other) –are the sole reason and I defy anyone to say different. This is NOT a theory — this is proven fact as anyone could see if they just took the time to do as I did; read the internet carefully, paying attention to all the side trails and seemingly dead ends. Nature speaks and we must listen. Even if the voice you don’t hear didn’t come from that direction!

      Oh, and what do you mean entropy, there is NO such thing, any tool, err, fool, can see that the universe has no winding key, no mainspring to catch on the door edge and spill the beans out on the floor and with the chamber maid still blaming me from last week, well, I guess she’ll never do that again!

      Mike C (I think, therefore I… what was I saying again?)
      -grins-

      • damian says

        haha, Your right of course, My theory is biased commercialism. Even though I read about it on the inter web and naturally assumed it must be so. The theory, validated by observed and repeatable practice was most compelling. Especially on toast. 🙂

        I have seen the error of my ways, no more will I study the Internet, but instead get my facts from books. So where to start, hmm, who is this Fred Hoyle guy ? 🙂

  13. Member
    Jon says

    One question seems obvious to me and I’ve thought about it for a while. Why not take all of our observations about relative velocities and distance and write a predictive simulation of the universe that tells us what is happening “now” at any given place in the universe? No small task, but it would certainly help us understand the bigger picture. Once some semblance of that is gathered together, what’s to stop us from running the simulation to it’s conclusion? Something like that also seems necessary for travel outside our solar system at high rates of speed.

  14. As to a center of the universe:

    Most measurements and observations concerning the observable universe have concluded that it is Euclidean and flat or close to it. Despite these observations most theorists believe that the universe on a much larger scale curves according to Riemannian geometry and GR. If so then the universe could curve around on itself and would have no center to it. This is the presently preferred configuration by many or most theorists.

    If the universe is entirely flat, on the other hand, then it would have a central geometric location to it. In such a model the density of matter would seemingly decrease toward outbound locations. In an expanding but finite universe the overall density of the universe would be decreasing as a whole as it would be increasing in volume as well as its boundaries.

    • Hon. Salacious B. Crumb says

      …. sniff’n too much ether, methinks!

    • Lawrence B. Crowell says

      The spacetime curvature of the universe is largely in how the 3-d spatial surfaces are embedded into the 4-d spacetime. This curvature tells how points in one surface are separated further as that surface is moved up along time to the next surface. The spatial surfaces appear very flat though. However, we can never prove astronomically that they are absolutely flat. They might just be very large spheres so that our little local region extending out to 45 billion lys appears flat. There might in the end be some tiny angle of deviation from 180 degrees between three very distant galaxies or points that we are unable to measure.

      To substantiate a flatness of space to a higher level of confidence the flatness may be associated with some quantum numbers of a topological nature. These might be confirmed in particle experiments, and the relationship between gravity, cosmology and the structure of quantum fields might lend additional weight to the flat space universe. However, as with all science this is still not a proof of flatness. In science we do not prove things to be true, or confirm things absolutely.

      LC

  15. @ Hon. Salacious B. Crumb

    Like you I try to be honorable. Salacious, I certainly am. Sniff ether (aether) with every breath. Sniff petroleum ether? only when I start my lawn mower.

    @Lawrence B.C.

    You are certainly knowledgeable and well written concerning mainstream views. I also notice that you admirably qualify your statements concerning possibilities. I think this is very important for all science since time has continued to cleanse away almost all prior theory which I think will continue to happen for the foreseeable future.

    I think there are very few present theories that have a solid foundation that will withstand the test of time: a few might be chemical theory, natural selection, plate tectonics for example. The other most fundamental theories for the most part, I believe, will almost totally be replaced. Even these “solid” theories mentioned still contain many unknown facets that need to be filled in.

    • Hon. Salacious B. Crumb says

      Wow It has taken you nine days to decide on a comeback. Pretty week. Herd it all before.
      Attempting the last word on an archived article shows how desperate you are to get some attention.
      Again. Your Pan Theory is truly hilarious! Wow, you even profess and have the audacity of your own version of Relativity!!! Need I say more…

  16. Hon. Salacious B. Crumb says

    Message for Universe Today.
    Please, please, please!.
    Stop supporting the nutters, so people like me will not have to go onto the offensive. I’ve spent and awful lot of time utterly denouncing these individuals, either pointing out the errors or mocking them. Yet as a reward, you just keep letting the nonsense flow.
    Seriously. If anyone is going to read and learn about astronomy, cosmology, or any decent science, you’ll have to start deleting these personal theories. They simply aim to send all these comments of the rails, and make legitimate science look stupid or wrong.

    Please stop aiding pseudoscience!

    It just gives this site a very bad look!

  17. Hon. Salacious B. Crumb says

    Another comment.
    Might be an idea to close the comment after only a week of a few days.
    Most of what is to be said appears in the first day or days.
    It will stop individuals like this sneak in the last word, who do it just to sound authoritative.
    Thanks

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