I have a few problems with these theories on the universe. Why am I wrong?

Factual Questions
1

I’ve got a few issues with some theories I see commonly presented. Do any of these theories hold water? If so, what’s wrong with my logic?

  1. Every time I see a program on the multiverse (Brian Greene’s Nova episodes, “The Universe”, “Through The Wormhole” for examples), the program always brings up the possibility that there are countless universes. The theory is that if I flip a coin and see heads, I’ve also created an alternate reality where it came up tails. So all possibilities exist somewhere. I don’t remember the name for the concept.

This is complete nonsense to me. Suppose while the coin was in the air I decided to shout out numbers as fast as possible? If I can get 10 numbers out, that’s 10^10 possible universes. Suppose you take into account where the coin landed? Suppose I take a breath. I could inhale 1 to 30 billion atoms. Seems to me that an infinite amount of possibilities always exist for anything you ever do if you get down to it. This theory seems too stupid to mention at all, yet I’ve seen it time and time again.

  1. An infinite universe. If the universe is curved this issue is non-existent for me. If it is not curved, then the matter that exists must stop somewhere. My logic is simple (to me). If we started with a singularity, where all matter was contained, then it simply cannot have moved to infinity distance. If the universe is infinitely spread out with matter, then it was infinite a billion years ago. And a billion years before that. And so on, until the singularity. Basically, the way I see it, no matter how fast inflation was, there’s no way to move something from a singularity at the big bang to be infinitely many light years away from us. We can see 13 billion light years away. To me there very well could be matter and galaxies 100 billion light years away. Space is expanding faster than light between those galaxies and us so we’ll never see them. But they can be there. But there must be an END to the distribution of matter if it all started in one point. [Disclaimer - that’s not to say that 10^100 light years away there’s not another universe as well, just that our own universe must stop sometime.]

  2. Dark matter. My understanding which is admittedly weak is as follows: We calculated that galaxies should fly apart because they do not have enough mass. We can’t see that mass. So we created a form of matter in our minds that exists all over the place and conveniently declared that it does not interact with regular matter, except for gravitationally. Seriously? Creating something you can’t see, touch, test, etc to explain how something works? Humankind has been doing that for millennial and it’s called religion.

Why can’t this dark matter just be regular old dark matter? Something such as failed stars, planets, black holes, or just plain old dust? Spread a bunch of that out in our galaxy and we won’t see it in telescopes. Couldn’t that hold our galaxy together?

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There’s a thread from just a few days ago discussing Dark matter and dark energy. The gist is actually rather along the lines you just suggested: That “Dark matter” is something of a fabrication, invented as a “placeholder” to fill a gap in the understanding of what’s going on out there, until some better data is collected somehow.

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  1. Read Brian Greene’s The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos. In it he describes nine different types of multiverses, based off nine different mathematical and physical models. The type of multiverse you describe is one of them, though you’ve garbled the notion behind it. You need to read seriously. Greene builds each type of model slowly and gradually, but the concepts require attention and understanding. What’s important to remember that however well he puts them into words, they are all really mathematical in origin. Words are a convenience but they can’t be refuted by other words.

  2. If the universe is infinite today, then it must have been infinite when it began. Please don’t say this is impossible. Nobody yet knows whether it’s true or not but it’s not impossible.

  3. Yes, many people have offered explanations for dark matter that include plain old ordinary baryonic matter. Others say these have insurmountable problems and offer other, physically quite sound, explanations involving more exotic matter. We don’t know the answer to this either, but all the explanations either conform to physical principles and provide possible calculations that let them be tested against known observations or else they are dismissed out of hand. If they can’t be dismissed, then they are possibilities until proven otherwise.

One of the first things that is hammered home in mathematical logic courses is that a false premise can produce any answer. Not a wrong answer: any answer. Answers that may be true or false or float somewhere beyond any sense of physical reality.

Your premises are all false. They’re based on ignorance, so they’d almost have to be. Ignorance is not a bad state. We’re all ignorant of almost everything on every subject.
The problem is that I can’t tell whether you’re interested in doing the work to change this or you just want to whine that science is hard. If you want to do the work, stop watching television. There’s not a single program that contributes any real understanding. Read some books. We’re living in a Golden Age of popular science written by working scientists. Take advantage of it.

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As luck would have it, I’m now 4 lectures into a series by The Teaching Company on Dark Matter and Dark Energy. The professor is Dr. Sean Carroll, Cal Tech.

It’s a good series.

I appreciate that this doesn’t answer the OP, but this detailed lecture series is going to take a bit longer for me to work through. For now, I can only report that very sensible sounding people have been working awfully hard on this, seemingly considering all of the [spacetime warped] angles. Me, I’m feeling nearly as ignorant as earlier, but on a much more elevated plane.

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1.)It’s worse than that even. From the moment you have decided to flip the coin to the moment it lands, the universe would have split 10^(stupidly high number) times. It does this constantly whether or not you are flipping coins.

At least, that’s where the math takes us. Paradoxes are good, because they show where we need to learn more, and solving them lets us know new and interesting things about the universe. Most physicists are not comfortable with the infinitely splitting universes, and try to find how to resolve the math that implies they exist with the “intuitive” notion that they don’t.

2.)The universe did not start at one point. It was already infinite when it started. We can actually see much farther than 13 billion light years, it’s something closer to 47, i believe, because the universe is still expanding.
Even if it did have a single point at the beginning, which is wrong, but still works from some perspectives, (every point of the universe began at a single point) the fact that it had accelerating expansion much faster than the speed of light still puts it into the lower order infinities. So you see any two points that started infinitely close together would be an uncountable infinite distance away even only instants later.
3.)Religion is an answer looking for a question. Dark matter was never something that cosmologists looked for or tried to prove. In order to get their proposed models of gravity to line up with observed reality, they found they needed another constant… a fudge factor if you will.
Try to model galaxy rotation and evolution without the fudge factor, ti doesn’t work, with it, it works well. It makes predictions that are borne out by further experiment. Dark matter is a very real thing, it was not created, nor asked for.
However, just like the particle zoo at the beginning of the particle physics age had physicists scratching their heads and asking “Who ordered that?”, dark matter is another thing about the universe that we can learn to see how it operates. If the galaxy models had lined up with predictions, they would have called it a successful experiment and gone on to something else. Instead, we get to learn something new. There may be many different things that make it up. Point is, it’s a whole new realm of the universe in which we get to learn.

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Try to model galaxy rotation and evolution without the fudge factor, ti doesn’t work, with it, it works well. It makes predictions that are borne out by further experiment.

What experiment?

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As I understand it, it’s because if there was that much of our kind of matter around shortly after the Big Bang when the universe was dense enough for nuclear reactions to occur, it would have affected elemental abundances in ways we don’t see. Therefore, a great deal of whatever is out there has to be something that doesn’t contribute to nuclear reactions, which rules out normal matter.

I think they meant “observation” rather than “experiment”. Here’s an example; a filament of dark matter stretching between galactic clusters detected by its gravitational lensing. Such things were predicted to exist, and apparently there it is.

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Your argument here is essentially that it doesn’t seem right to you. So the fault in your logic is to assume that the universe must behave in a way that does seem right to you… :stuck_out_tongue:

Less facetiously, the motivation for such a kind of multiverse comes from quantum mechanics: without it, you need to postulate a fundamental, unanalyzable, ad-hoc dynamics that by some mysterious process manages to single out one ‘real’ possibility from the ones that quantum theory offers: remember, quantum mechanics only yields probabilistic predictions, i.e. there’s a certain probability for A to happen, some probability for B, etc. It doesn’t offer up any kind of explanation as to why, say, A happens to the exclusion of B, C, D and so on. So in this sense, the argument goes, it’s natural to expect that these alternatives occur as well, just in such a way as to not be able to interact with one another – in different universes, so to speak.

It’s actually quintessentially scientific: your observations disagree with your theory; you come up with a new theory to fit the observations; you extract predictions from the new theory, and test them against experiment (one such prediction would be, for instance, the gravitational lensing from structures such as the bullet cluster).

Plus, in a sense, the existence of dark matter may be a consequence of a theory called supersymmetry, in which every known, ordinary particle has superpartners, which must be much heavier in order to not have been discovered in particle accelerators by now. The lightest of these particles has nothing to decay into, and thus, is stable, producing the expectation that there should exist a large amount of mass in the form of particles differing from the familiar ones, which is exactly what we observe in dark matter.

Of course, nobody knows if supersymmetry applies to the real world, and there are alternatives to dark matter (such as MOdified Newtonian Dynamics or MOND for short), but these are becoming less and less likely as the evidence for dark matter mounts.

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Once you grasp the concept of an infinite universe, the leap to an infinite amount of infinite universes isn’t that hard. After all, infinity is infinity, no matter how you parse it.

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Possibly, but I seriously doubt I’ll ever be able to ‘grasp’ the concept of an infinite universe in any remotely concrete way…

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Neither can I. However, once you’ve got one infinity, another infinite number of infinities doesn’t make much of a difference, does it?

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The integers are composed of a countable infinity of points. The number line, however, is composed of an uncountable infinity of points. If you take away all the rational numbers from the number line you have an infinity of holes but they comprise 0% of the length. IOW, the difference between infinities is both real and meaningful.

I think all the multiverses Greene refers to are countable infinities, but that doesn’t mean those are the only possibilities. Discovering an uncountably infinite variation of the multiverse would be a feat.

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You are referring to the Many Worlds Theory of Quantum Mechanics, discovered by Hugh Everett III
in the 1950s and published as his PhD thesis (John Archibald Wheeler was his thesis advisor).

Scientific American Article

The logic of theory is 100% airtight. That does not mean the theory is correct; our technical ability
is not yet up to the project of testing it.

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I have no real “book learnin’” on this topic, just an opinion, which seems to be the criteria for posting on several of these internet forums.

I think back to the days of physics before Albert Einstein and try to draw an analogy between his discoveries, which push much of modern day physics in the direction it is taking, and the bright young physicists of today who strive to discover the true nature of scientific anomalies like dark matter. Going further back, before Issac Newton’s theories and laws of gravity, I wonder if folks even began to imagine how far our knowledge would unfold after Einstein’s Theory of Relativity.

My point, we don’t know what we don’t know. But, using scientific methods based on what we do know will lead to, not only, concrete answers but even more questions. Like the folks in Newton’s time, we constantly evolving and learning about what is around us, seen and unseen. Thank God we are still ignorant and not convinced we have all the answers. Humility leaves room for growth.

There, now you have an artist’s perspective as well.

Only two things are infinite, the universe and human stupidity, and I’m not sure about the former.
-Albert Einstein

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One thing I never see addressed: is dark matter believed to be tangible?

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A couple additional questions:

1: Does general relativity work exactly like special relativity with respect to mass? At relativistic speeds, relative mass increases, to the point that accelerating to relative c, the nominal mass of the entity approaches infinity, which is why anything that has rest-mass cannot reach the speed of light. If gravitational distortion has the same effect, does that mean that if I throw a rock into space (I have a really big arm), after it passes, say, Sedna, it will literally be less massive than it was lying on the ground at my feet? Is a dust cloud of 10^30 motes ten AU across less massive than the same matter accreted into a body 10m in diameter, and in what way does this affect dark matter modeling?

0: How does theory address the possible “plasticity” of spacetime? If a body distorts spacetime locally, is there a remote conservation effect, a sort of anti distortion? For example, imagine spacetime as a gaseous medium of inertia – a massive body rarifies the medium around it so that your inertia is unbalanced, causing you to move toward the body – might there be an increase in “density of the inertial medium” elsewhere, a sort of “gravity ridge” and in what way would such an effect affect dark matter modeling?

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Not if it’s genuinely ‘dark’, which in this context means ‘doesn’t interact electromagnetically’ (as opposed to dark in the sense of non-luminous ordinary matter). In this case, it would interact at most via the weak interaction, and thus, be as fleeting as neutrinos – which accounts for the fact that it’s so hard to detect (if there is such dark matter, you are actually perpetually in a ‘sea’ of it, without noticing anything).

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Define tangible.

One leading theory is that dark matter is composed of neutrinos. Neutrinos are certainly particles, and are known to have mass. Yet they are more non-interactive than any other known particle. In the classic image, they could pass through light-years worth of lead without pause. Uncounted billions are passing through your body this second.

Another theory says that they are black holes. Are black holes tangible?

Lots of earth-based notions don’t work well in the cosmos.

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Nope, that’s the whole reason it’s dark. All tangible things either emit or reflect light. Even the darkest solid thing you can imagine is still giving off some kind of radiation. The whole reason anything is “tangible” is because of the interactions of the electrons in them.

Dark matter particles do not appear to be subject to electric forces. There’s a possibility that they may be subject to the weak nuclear force, but as far as we can tell, they only interact due to gravity. Which means two globs of dark matter will pass right through each other, as well as any normal matter.

Mass is mass, no matter (heh) how fast it’s going. A ping pong ball with mass m will have the same mass whether it’s sitting still or going at .9c. It’s momentum will become relativistic, which is why the faster something is going, the harder it gets to accelerate it. The whole “relativistic mass” idea isn’t in common use anymore because it was too misleading.

So what I think you are asking is, if mass gets higher due to high speeds, does mass get higher due to high gravity? The answer is no, since mass doesn’t actually increase with speed.

You mean like if I have a rubber sheet and I place a bowling ball on it, a bump must appear somewhere else on the sheet? I’m not aware of any conservation of curvature type of law. The only instance of negative curvature I can think of is dark energy, and no one’s really sure what that’s all about.