The Perplexity of the Cosmos

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Discussion by: ScienceIsTruth01
There are many theories to the origin of the universe. The most commonly accepted theory is the Big Bang. The Hot Big Bang was started at a singularity at a point in space-time that was infinitesimally dense and hot, which resulted in a hyper novae explosion that released the matter of the Universe. The universe has kept on expanding but it’s speed of expansion has slown down. Newton’s laws dictate that a body or mass in motion will remain in motion unless something interferes with it, and also, by logic, with the amount of possible interference something that moves must also eventually stop moving. At first this appears to be a contradiction, but is it? Gravity has slowed down the expansion, but physicists have said that gravity alone would be too weak to have slowed down the unvierse to the speed it is at now. The question is, what else besides gravity can slow down the speed of the universe. The theoretical answer, in my opinion, is dark matter, the very fanric of the cosmos. Dark matter fufills Einstein’s cosmological constant, and with the recent discovery of the Higgs Boson and the proving of the Poincare Conjecture, in my opinion, one can solve the existence and mass gap problem of yang mills theory by substituting the ghost gluon as the Higgs Boson and the ghost propagator as dark matter/dark energy. Also the proof that Black Holes do exist and are detectable, as shown by Hawking and Penrose in their theories and by Hewish and Ryle, whos pioneering of radio astrophysics made the detection of pulsars and later Black Holes possible. If anyone has any different ideas or suggestions please respond, this has been a curiosity of mine since i was about 10.

17 COMMENTS

  1. That’s what dark matter and dark energy hypotheses are about, isn’t it, or am I missing something? As far as the nity-gritty of it, I don’t know. I think there is a lot of room for discovery here, especially with better, more accurate tools and methods. One day, I’m pretty sure we’ll know.

  2. I was unaware the expansion was slowing down

    this is difficult quantum mechanics at work anyway so I’ll avoid responding but the inflation model means the universe expands much faster than the speed of light, spacetime itself expanding not just matter flying apart, secondly

    • In reply to #2 by SaganTheCat:

      I was unaware the expansion was slowing down

      this is difficult quantum mechanics at work anyway so I’ll avoid responding but the inflation model means the universe expands much faster than the speed of light, spacetime itself expanding not just matter flying apart, secondly

      No the expansion doesn’t go faster than light because it’s light, and nothing goes faster. Galaxies can move away from each other faster than that, but they themselves cannot exceed the speed of light.

      • In reply to #5 by DocWebster:

        In reply to #2 by SaganTheCat:

        I was unaware the expansion was slowing down

        this is difficult quantum mechanics at work anyway so I’ll avoid responding but the inflation model means the universe expands much faster than the speed of light, spacetime itself expanding not just matter flying apart, s…

        I was referring to the expansion of spacetime. assuming we accept cosmic inflation theory then FTL expansion must have happened in the first moments of creation. I was thinking back to a book called “The Goldilocks Enigma” by Paul Davies. Not got the book to hand so I googled bits and found this snippet

      • In reply to #10 by naskew:

        In reply to #2 by SaganTheCat:

        I was unaware the expansion was slowing down

        I was under the impression it was getting faster. The following link seems to confirm that this is the current thinking amongst the scientists too. http://www.space.com/17884-universe-expansion-speed-hubble-constant.html

        Thanks! I was sure the consensus was that it was accelerating too.

        I think the OP needs a link to explain “slowed down”. does this mean there is a slowing or could this be referring to the early inflation that slowed down suddenly, Electroweak Epoch which I assume is to do with quantum mechanics, if so I refer to my original response that it’s far to complex for my little brain.

  3. To the OP, I recommend Brian Greene’s first two books: The Elegant Universe and The Fabric of the Cosmos. Both very readable and they go into all this stuff. What I like about Greene is he really has a nack to be able to not dumb things down so much as some science authors do but also to still explain it so it’s understandable to people who don’t have advanced degrees in physics.

  4. Wikipedia has a good article on Physical cosmology that gives a good overview of what we know, what we don’t know, and why we know it regarding the beginnings, evolution, and fate of the universe.

    The evidence for dark matter is mainly not enough visible matter in galaxies to account for their structure and speed of rotation. The observed “flatness” and evidence of the universe’s expansion de-accelerating leads to the conjecture of dark energy.

    It is mainly general relativity, not quantum mechanics, used for this sort of cosmology.

  5. The expansion of the universe is speeding up. The conjecture is that it is due to the repulsive nature of empty space, “Dark Energy”.

    I would also recommend Brian Greene’s books. He is an advocate of string theory. But a recent book by Laurence Krauss called “Something from Nothing” is getting some traction. Krauss is a good friend and supporter of Richard Dawkins, and there is a televised conversation on YouTube where Krauss interviews Dawkins about evolution, then Dawkins interview Krauss about his “Something from Nothing” theory. (The second half of the video) At this link below. Its a good watch because they dispose of religion as well at each turn.

    http://www.youtube.com/watch?v=YUe0_4rdj0U

    The core of Something from Nothing theory is the conservation of energy law. If the universe started from nothing, zero energy, then if you sum all of the energy in the universe, all the matter and dark matter on the positive side, and all the dark energy on the negative side, if they are equal, they cancel each other out. So the universe does not need a creator, because it came from nothing, and it will return to nothing, zero energy. Krauss explains it a lot better than I can.

    In relation to the speed of light, the rule is that light can only travel at a set speed THROUGH space time. But in the inflationary period of the big bang, space time, the fabric of the universe, can expand faster than the speed of light.

  6. ScienceIsTruth01, a lot of what you say is wrong, and to fully understand this field requires maths.

    The universe has kept on expanding but it’s [sic] speed of expansion has slown [sic] down. Newton’s laws dictate that a body or mass in motion will remain in motion unless something interferes with it, and also, by logic, with the amount of possible interference something that moves must also eventually stop moving.

    The universe’s expansion is currently accelerating, although there may have been a time in the universe’s past when it was greater. But Newton’s laws aren’t the right way to think about it, because we’re talking about how much space is created between galaxies, not ordinary motion of the galaxies themselves against a static space. The Friedmann equations$ are the correct way to understand what’s happening; the size of the universe is proportional to a function a(t), its time derivative is positive when the universe is expanding, and the second time derivative is positive when the expansion is accelerating. ($ Google them; you should probably also read a derivation of them somewhere.)

    physicists have said that gravity alone would be too weak to have slowed down the unvierse [sic] to the speed it is at now.

    Actually, the curiosity is why the expansion is still accelerating!

    The theoretical answer, in my opinion, is dark matter, the very fanric of the cosmos. Dark matter fufills Einstein’s cosmological constant, and with the recent discovery of the Higgs Boson and the proving of the Poincare Conjecture, in my opinion, one can solve the existence and mass gap problem of yang mills theory by substituting the ghost gluon as the Higgs Boson and the ghost propagator as dark matter/dark energy.

    That’s an impressive error density in such a space. The accelerating expansion is due to dark energy, not dark matter (the latter can’t be interpreted as the cosmological parameter); the Poincare conjecture is irrelevant to the mass gap problem; the Higgs boson and gluon can’t be ghosts because ghosts violate the spin-statistics relation; and ghost propagators can’t manifest as dark matter or dark energy for the same reason. (If you want to know more about what ghosts actually are, you should read about FP-ghosts in the BRST formalism. Unfortunately, the maths required to understand why search terms appear in the Lagrangian density is well beyond even a master’s degree.)

  7. I am not a scientist, but I attended a panel discussion a few years ago by cosmologists and physicists. There was general agreement that the universe “always was.” Can anyone give me the name of a scientist who writes about this theory? I find it fascinating. If I recall, I believe members of the panel did not deny the “big bang” theory, but talked about a universe preceding that–the one that “always was.”

    • In reply to #8 by Amaryllis:

      I am not a scientist, but I attended a panel discussion a few years ago by cosmologists and physicists. There was general agreement that the universe “always was.”

      I find this hard to believe. unless they were discussing alternatives to orthoxy. The observable universe is definitely of a finite known age (~13 billion years)

      Can anyone give me the name of a scientist who writes about this theory?

      well Fred Hoyle maybe but that was along time ago. According to wikipedia (the source of all knowledge!) http://en.wikipedia.org/wiki/Steady_State_theory

      In cosmology, the Steady State theory is a now-obsolete theory and model alternative to the Big Bang theory of the universe’s origin (the standard cosmological model).

      I find it fascinating. If I recall, I believe members of the panel did not deny the “big bang” theory, but talked about a universe preceding that–the one that “always was.”

      well there’s multiverses and so on

      • In reply to #9 by nick keighley:

        In reply to #8 by Amaryllis:

        I am not a scientist, but I attended a panel discussion a few years ago by cosmologists and physicists. There was general agreement that the universe “always was.”

        I find this hard to believe. unless they were discussing alternatives to orthoxy. The observable universe…
        But Nick what is actually observable?? I would submit that it is only the light which was generated up to 13.7 billion years ago. The matter from which that light was generated is surely here with us today in the present, some in 3rd or 4th generation stars and galaxies some is even in the molecules of which you and I are constructed. Perhaps we can see and record (photograph) images from the history of the universe. Maybe the observable universe is just light, with no matter, a photo-album of very high energy events which occurred when the universe was far from the Goldilocks zone which allows us to be in the year 13,700.000,000 after Big Bang.

  8. Oh I can just see the religios rubbing their hands in glee at all this scientific “uncertainty” !

    Time to step in and create a smokescreen of impenetrable ” certainty” lads !

    (Well mostly lads.)

  9. I don’t know if it is worth dredging this discussion up again but I just noticed it after the recent amazing observations of B-mode polarization.

    I’ll note that the expansion of the universe is described by General Relativity (GR). The main idea of GR is that energy type and energy density determine the behavior of space and time.

    The most basic way to categorize the stuff (energy densities) of the universe is: 1. radiation[light] (produces attractive gravity, dilutes as 1/distance to the fourth power) 2. matter[normal and dark] (produces attractive gravity, dilutes as 1/distance cubed) 3. dark energy [vacuum energy] (produces repulsive gravity, constant energy density; does not dilute)

    At times before about 10^-43 seconds (Planck time) GR does not work and we can therefore say nothing useful. We can only assume by extrapolation that the universe began at t=0 but there is no way of knowing that as GR fails. Shortly after this Planck time the universe was dominated by a vacuum energy (the inflationary period) resulting in a approximately exponential expansion (since this type of energy produces repulsive gravity in GR). The transition out of inflation is what gave our universe its expansion rate (momentum if you want), heat and particles.

    At very early times before about 55,000 years after the big bang the distance scales of our observable universe were so small that radiation dominated the energy. Radiation produces attractive gravity so the expansion of the universe slowed during the time ~t^(1/2). Since radiation energy density dilutes more quickly than matter, the universe became matter dominated after about 55,000 years. Matter still produces attractive gravity so the expansion still slowed but at a different rate: ~t^(2/3). All the while the expansion dilutes matter and radiation energy densities but the small vacuum energy density is constant. After about 7 billion years the matter energy density diluted enough that the universe becomes vacuum energy dominated. And that type of energy produces repulsive gravity in GR which is why we are in an accelerating, expanding universe now.

    I hope that clears up more than it muddles.

    • In reply to #16 by Northampton:

      After about 7 billion years the matter energy density diluted enough that the universe becomes vacuum energy dominated.

      Correction: After about 7 billion years the universe transitioned to a positive accelerating universe. After about 9.5 billion years the universe became vacuum energy (dark energy) dominated. So the transition to accelerated expansion occurred before the matter energy density / dark energy density transition.

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