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What Is The Universe Expanding Into?


duderonomy

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Bhim: Do scientists have hypotheses on what lies  "above" the balloon shaped universe (using your description)? I don't mean other universes, but the "space" beyond our universe?  Rip

 

Excellent question.  One of the problems with the balloon analogy is that general relativity doesn't require the balloon to actually be closed.  So asking what's "above" the balloon is really the same thing as asking what's "inside" the balloon.  In either case, the question is somewhat unanswerable because the universe is all that there is, and we've defined it to be the balloon's surface.  The higher dimension in which the balloon (or manifold, to use the more precise term) exists, is simply the mathematical context in which the universe exists.

 

Having said that, it is certainly possible that the universe we observe is simply a cross-section of some higher dimensional universe.  I tend to not believe this, because we three-dimensional beings are unaware of any two dimensional forms of existence, so it's hard to believe that anything might exist in a fourth spatial dimension.  However the idea of additional dimensions isn't entirely unfounded.  A few years ago Lisa Randall popularized the idea of extra dimensions being hidden in the hypothetical strings that make up all of matter, akin to how an effectively two-dimensional sheet of paper can be rolled up to get a seemingly one-dimensional object, which has a second dimension hidden within it.  This is an elegant hypothesis because it would explain why gravity is such a weak force.  You have no doubt noticed that a small refrigerator magnet is able to pull a paper clip, despite that the mass of the entire earth is acting against it.  Gravity is peculiar in that it is very weak, but some String Theories propose that in a higher dimension gravity is actually very strong, and what we detect as "gravity" is simply the true gravitational force leaking out of the higher dimensions of strings.  The idea of higher dimensions being a part of our existence doesn't seem to be contrary to the laws of physics.  But they are as of yet undetectable, so while String Theory provides hypotheses as to what may lie in higher dimensions, I reserve judgment until there's some sort of falsifiable statement made on the basis of String Theory.

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I'm also picking up a lot of terminology that I hope I can someday get through my brane (see what I did there?).

 

Yeah, I see what you did.

You just pissed off the crickets because for the first time in the history of ever, you just made them STFU and stare blankly into the camera.

Ha-ha!

I'm not sure what you mean, Fwee, but if I did something smart I assure you it was purely accidental!
Your use of the word 'brane' instead of 'brain' was both witty and funny in so far as how the word 'brane' pertains to the subject matter in this thread.

 

In some comedy, if someone says or does something that has a stupifying affect on the audience, the silence that ensues due to the event is usually, and quite comically, filled with the sounds of crickets.

 

In my mind, your use of the word 'brane' not only stupified the audience, but even the crickets didn't know how to react. So they, too, were quiet and just blankly stared ahead.

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Yes, BAA… very helpful.  Thank you!

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Bhim: Thanks for your response. I will reflect on your answer. I have very little background in science so I have to take my time and think it through. It's hard for me to think it throiugh when we are dealing with multiple dimensions because I can't picture it in my mind. But thanks again.   Rip[

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  • 2 weeks later...

duderonomy,
 

The universe is expanding. I get that...it's still on the move after the Big Bang. But what is the universe expanding into?

 

I've heard the analogies about the loaf of raisin bread in the oven, where the raisins (planets; galaxies) are in the bread and getting further apart as the bread bakes. But the bread as a whole is still expanding into the interior of the oven. The way I understand it, the interior of the oven is a finite place, and so I can say the bread is expanding into it.

 

What is the "it" that our universe is expanding into then? Is it a place? Is it a an expansion at the expense of nothingness, and if so, what is the nothingness made of?

 

If I look at the sky 10 billion years from now, I will see that the closest galaxy to ours has gotten further away from us. Where is it going to, and what is it displacing?    Mostly, and this is what I don't get...what would it be displacing?

 

I've wrestled with this for a long time and don't get much of what I've read about it. Can someone here explain it to me like I'm a nine year old, or recommend any books?

 

I hope this is the correct place to put this question.

 

 

 

As a reminder, I suggest you realize the the expansion of the universe is theory, granted presently well-accepted theory that the observed redshift of galaxies is explained by an expanding universe.  In this theory, the Big Bang (BB) model, galaxies are not actually moving away from each other as expansion would suggest, instead space is thought to be expanding which stretches out light and other electro-magnetic radiation to longer wavelengths over time, giving the appearance that galaxies are moving away from each other. But the universe as a whole would still be expanding without the real motion of galaxies.

 

Since space, according to this theory, is expanding, then would it be correct to ask what is it expanding into?  There is more than one possible explanation to this according to BB theory.  One hypothesis is that space is an infinite continuum where the measured distance between galaxy clusters will measure to be increasing as space expands. Another explanation is that as space expands new space is created and  increases dimensionally as measured by increasing distances between galaxy clusters over time.

 

According to General Relativity, space bends according to Riemann Geometry and accordingly can result in different configurations of an expanding universe. To date the observable universe appears to be "flat," a simple 3 physical dimensioned reality -- with no indication of curving (which could still occur beyond the observable universe).  If the universe were flat it would be the simplest configuration where an expanding universe would expand equally in all directions, an  "open" universe that may or may not be spherical as a whole. The other possible configurations according to General Relativity limit the direction of the expansion of space. The model that closes the universe in all directions concerning its form, is called a spherical universe that is closed in that going in a straight line in any direction would lead to eventually coming back to the same point. The other configuration is called a hyperbolic configuration,  "the saddle," whereby space would not expand uniformly in all directions. In all of these models expanding space would also involve the creation of new space.

 

http://en.wikipedia.org/wiki/Shape_of_the_universe

 

These are not explanations that a normal 9 year old could understand according to your request  sad.png but a simpler explanation would probably not be a mainstream explanation. It would probably involve a simpler definition of space. Maybe the simplest of such definitions, explanations and theories, would be that "space is the distance between matter, the volume which matter and field occupies and nothing more."  As René Descartes hypothesized, space would be an extension of matter.

 

From this definition, perspective, and theory, space would be a very simple thing which could not bend, warp, or expand. Such a simple explanation would be contrary to both the BB model and General Relativity therefore it would require another theory and cosmology to explain cosmic redshifts other than by the expansion of the universe or space. There have been many of such proposals but most are little known or seriously considered by mainstream theorists today because such proposals would be contrary to presently well-accepted theory.

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Thank you Pantheory, as well as Bhim and BAA and the others who have helped me. I'm just finishing my sixth book on this (again, from the juvenile section of the library, because that's where my knowledge of this is at this time) as time allows, and as I reread the explanations posted here at least I'm starting to get a grasp on what the current theories are.

 

I've always been a bit in awe of the Universe and how it works, but sadly never took the time to look into it much before because I thought the understanding of it would be beyond me. Now that I've been bitten by the bug to know I have to admit it's even more fascinating then I ever thought it was.

 

Growing up I always imagining that Biblegod was everywhere, so there was no place where there was nothing. I don't believe in any gods anymore, but I'm still having a hard time wrapping my brain around there being nothing. Like I said in an earlier post, even nothing must be something.

 

Dark matter and dark energy, if they exist, exist in our universe, so they would be no different in that way then any of the matter and light and the other forces we do know of.  In other words, if the Universe is expanding, they are going along for the ride too. They are not what it is expanding into.

Time, although I am swimming smack dab in the middle of it all the time (no pun intended), is weird. It looks to me like something to think about as I get older, but now I'm learning it's part of a fabric with space? Thanks Einstein, for making my brain hurt.

Quantum stuff? Fuggetaboudit.  Maybe later I'll get into how something can be a one and a zero at the same time, or at least change from one into the other. Maybe that will be the answer to this question I can't quite grasp.

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Be advised that Pantheory is a proponent of plasma cosmology. Plasma cosmology is an alternative to Big Bang cosmology which has virtually no support in the scientific community. I only learned about it in grad school through emails I got from various shady individuals trying to convince me of their unsupported hypotheses.

 

Apologies in advance to Pantheory if I've misrepresented him.

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What if space is endless and all the stuff in the universe is expanding outwards forever.

Well, that's not quite right since this interpretation doesn't explain the observer-independence of galactic recession.  From earth we see every distant galaxy receding away from us, as though we were the center of the universe.  But if I were an observer in one of these distant galaxies, I would see the same thing.  If it was the matter in the universe that expanded, rather than the universe itself, then I would not be able to observe the same effect from any position in space.

 

Also, it's not true locally for gravitationally-bound systems.  Clusters of galaxies don't break apart due to the expansion of space.  As I said earlier, the Andromeda galaxy is actually moving towards the Milky Way.  And if you and I were in the same room, we wouldn't be moving away from each other due to the expansion of space.  So it really is the space itself, and not the stuff inside the space, that is expanding.

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  • 3 weeks later...

Be advised that Pantheory is a proponent of plasma cosmology. Plasma cosmology is an alternative to Big Bang cosmology which has virtually no support in the scientific community. I only learned about it in grad school through emails I got from various shady individuals trying to convince me of their unsupported hypotheses.

 

Apologies in advance to Pantheory if I've misrepresented him.

 

You are correct Bhim that I support an alternative cosmology but not Plasma Cosmology. I support my own formal cosmology that will go un-named here since its details seem unrelated to the query of this thread. The details and support for alternative cosmologies in general are little known to mainstream theorists and astronomers because few details of these, excepting for historical reasons, are in mainstream education curriculum. Much independent study would be needed to understand just a sampling of the great many alternative cosmologies and the possibility of their individual validity, or possible advantages thereof.

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Be advised that Pantheory is a proponent of plasma cosmology. Plasma cosmology is an alternative to Big Bang cosmology which has virtually no support in the scientific community. I only learned about it in grad school through emails I got from various shady individuals trying to convince me of their unsupported hypotheses.

 

Apologies in advance to Pantheory if I've misrepresented him.

You are correct Bhim that I support an alternative cosmology but not Plasma Cosmology. I support my own formal cosmology that will go un-named here since its details seem unrelated to the query of this thread. The details and support for alternative cosmologies in general are little known to mainstream theorists and astronomers because few details of these, excepting for historical reasons, are in mainstream education curriculum. Much independent study would be needed to understand just a sampling of the great many alternative cosmologies and the possibility of their individual validity, or possible advantages thereof.

Got a link to one of your papers on ArXiv? As you know, I'm a trained astrophysicist, so hopefully it won't be over my head. The claim that it would be incomprehensible to me due to the relevant theory not being taught in curricula is spurious because, after all, original research is by definition original.

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I want to thank you all again for your input in this thread. I've read most of the stuff my local library has on cosmology and of course I'm exploring what I can find on the net. it takes me while because I'm starting almost from scratch.

I keep coming back to re-read some of the posts and every time I do I understand the ideas a little better.

 

Now I've got another couple of questions that I haven't found answers to yet.  We know that electrons have their own 'orbits' around a nucleus of an atom, and the Moon around the Earth, and the Earth around the Sun. Stars however, other than in a binary system or because of a gravitational pull, don't seem to orbit around anything else. Is this true, and are there any theories about what galaxies themselves might orbit around, or does the orbiting thing end with planets?  

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Dude, stars tend to orbit around the centres of galaxies; however, there are many so called "rogue" stars and planets. While you put orbit in quotations when referring to an electron you must understand that you cannot think of these orbits as being anything close to a planetary orbit. Any classical analogy breaks down here. You can think of a standing wave analogy or a cloud of probability density but even these models have their limitations. It's not intuitive and while people (myself included) often throw terms like "orbital" around and make classical analogies such as "shells" and "pairs of electrons" without much thought. We do so because the analogy works under a very limited set of circumstances, but quickly breaks down. Please do not allow yourself to seriously entertain the concept of an electron orbiting like a planet. The analogy is so poor that it has little ability to predict much.

 

Edit: Typo

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I want to thank you all again for your input in this thread. I've read most of the stuff my local library has on cosmology and of course I'm exploring what I can find on the net. it takes me while because I'm starting almost from scratch.

I keep coming back to re-read some of the posts and every time I do I understand the ideas a little better.

 

Now I've got another couple of questions that I haven't found answers to yet.  We know that electrons have their own 'orbits' around a nucleus of an atom, and the Moon around the Earth, and the Earth around the Sun. Stars however, other than in a binary system or because of a gravitational pull, don't seem to orbit around anything else. Is this true, and are there any theories about what galaxies themselves might orbit around, or does the orbiting thing end with planets?  

 

This is actually a much simpler question.  All matter is universally attracted to all other matter, so of course the stars in each galaxy orbit about their galactic center.  In fact the stars at the center of our own galaxy are close enough to the central supermassive blackhole that their orbits can be seen in just a few years of observational data.  Back when I was in grad school someone who worked with such data gave a colloquium, and he showed an animation of images from these stars over time.  You can see them trace out Keplerian orbits, it's pretty cool to look at.

 

The universe in general is a pretty dynamic place.  As I mentioned in several earlier posts, it's possible to observe the nearest galaxy, the Andromeda galaxy, moving towards our galaxy via its blue shift.  Galaxies in galactic clusters also exhibit bulk orbits about the centers of their respective clusters.  It is important to know that gravity is not a peculiarity of the solar system.  Every particle in the universe with mass attracts every other particle with a force that depends on the masses of the two particles and the distance separating them.  Indeed, the universality of gravity is a hallmark of Newton's theory of gravity, and this aspect of his theory was by no means supplanted by Einstein's general relativity.

 

Regarding electron orbitals, as Rogue Scholar said it's not proper to regard them as "orbits" in the sense of planets about stars.  Atomic structure can only be described by first regarding matter as consisting of waves rather than discrete particles (of course it is possible to recover the idea of a "particle," otherwise we wouldn't be able to talk about electrons at all).  These waves are constrained to obey a partial differential equation called a wave equation, similar to the equation that describes waves on a string or sound waves in the air.  By treating the electron as a wave, it is possible to predict all kinds of observable physical phenomena, including atomic line spectra.  The wave equation for the hydrogen atom, in particular, has an analytic solution, i.e. it can be solved exactly without the need for numerical approximations.  Given what's in Rogue Scholar's avatar, perhaps I should leave it to him to go into greater detail on this.

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I'm starting to understand a bit of what you guys are saying.  For example, when Bhim, above, said, "as Rogue Scholar said", I understood that he was referencing an earlier statement made by Rogue Scholar.

 

This stuff isn't so hard after all.  ;)

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Thanks again all of you. I appreciate you all helping me with these questions.

 

I did put orbit in quotes referring to an electron because I remembered reading that it isn't really an orbit in the way that, say, the moon orbits the Earth. What I was thinking about were patterns, like everything from the smallest particle to the largest things known revolving around something else. 

I do understand that even in the expansion of the universe matter can be attracted to other matter and become closer together as expansion continues i.e. the Andromeda and Milky Way galaxies (I may not say it very well though). I do understand about rogue planets, stars, and the occasional scholar.

 

I wasn't thinking I guess when I asked if stars also orbited anything, having just read about stars orbiting their galactic centers. My blunder.

I didn't know that galaxies also revolve around something at their centers.  

 

So now I wonder, what is the current thinking, if any, on what the universe might be orbiting? I imagine this would be a hypothetical and not a theory from math and certainly not from observation. Could the entire universe, expansion and all, be being drawn towards the center of something the way a star is drawn towards a black hole? Maybe "in orbit around" would be a better way of putting it than "drawn" to.

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I'm starting to understand a bit of what you guys are saying.  For example, when Bhim, above, said, "as Rogue Scholar said", I understood that he was referencing an earlier statement made by Rogue Scholar.

 

This stuff isn't so hard after all.  wink.png

 

Well if it makes you feel better, Richard Feynman said "I think I can safely say that nobody understands quantum mechanics", and yet I feel as though I do.  Clearly I'm doing something wrong. Wendyshrug.gif

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Thanks again all of you. I appreciate you all helping me with these questions.

 

I did put orbit in quotes referring to an electron because I remembered reading that it isn't really an orbit in the way that, say, the moon orbits the Earth. What I was thinking about were patterns, like everything from the smallest particle to the largest things known revolving around something else. 

I do understand that even in the expansion of the universe matter can be attracted to other matter and become closer together as expansion continues i.e. the Andromeda and Milky Way galaxies (I may not say it very well though). I do understand about rogue planets, stars, and the occasional scholar.

 

I wasn't thinking I guess when I asked if stars also orbited anything, having just read about stars orbiting their galactic centers. My blunder.

I didn't know that galaxies also revolve around something at their centers.  

 

So now I wonder, what is the current thinking, if any, on what the universe might be orbiting? I imagine this would be a hypothetical and not a theory from math and certainly not from observation. Could the entire universe, expansion and all, be being drawn towards the center of something the way a star is drawn towards a black hole? Maybe "in orbit around" would be a better way of putting it than "drawn" to.

 

Interesting question.  Intuition tells me that from symmetry arguments, we can say that the universe was created with no net angular momentum, and thus on a large scale wouldn't be spinning.  But more importantly, at cosmological distance scales the expansion force dominates over gravity, and more recent data has shown that the rate of expansion is currently increasing due to the pressure of dark energy.  So this would rule out the universe being generally drawn together.

 

That said, before the increased expansion rate was discovered, it was theorized that just as the universe began in a big bang, it might end in a big crunch.  So your hypothesis is by no means far fetched.

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Bhim, how can expansion be increasing?

 

I mean, if a baseball pitcher throws a fastball, it doesn't actually get faster after it leaves his hand. You mention an expansion rate, which may be observed, but what is an expansion force? You seem to be saying that this force is dark energy, something that was mentioned in the books I read but not in any real detail. 

Isn't it true that 'dark energy' is as yet unproven, in the scientific sense? 

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Dude, remember, science does not "prove."

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Be advised that Pantheory is a proponent of plasma cosmology. Plasma cosmology is an alternative to Big Bang cosmology which has virtually no support in the scientific community. I only learned about it in grad school through emails I got from various shady individuals trying to convince me of their unsupported hypotheses.

 

Apologies in advance to Pantheory if I've misrepresented him.

You are correct Bhim that I support an alternative cosmology but not Plasma Cosmology. I support my own formal cosmology that will go un-named here since its details seem unrelated to the query of this thread. The details and support for alternative cosmologies in general are little known to mainstream theorists and astronomers because few details of these, excepting for historical reasons, are in mainstream education curriculum. Much independent study would be needed to understand just a sampling of the great many alternative cosmologies and the possibility of their individual validity, or possible advantages thereof.

Got a link to one of your papers on ArXiv? As you know, I'm a trained astrophysicist, so hopefully it won't be over my head. The claim that it would be incomprehensible to me due to the relevant theory not being taught in curricula is spurious because, after all, original research is by definition original.

 

 

I've been out of state for a few weeks. Here is an answer to your request for links to my most recent papers. One paper describes perceived problems with present-day BB cosmology, and the other paper is a study of type 1a supernova proposing that dark energy is not real.  Some of the older supernova observations in this study led to the original proposal of dark energy, but in this study they have led to a contrary conclusion based upon a different cosmology.

 

http://www.ccsenet.org/journal/index.php/apr/article/view/32603/19463

 

http://www.aijcrnet.com/journals/Vol_4_No_9_September_2014/2.pdf

 

I hope to be able to put both these published papers on ArXiv later this year since I and my coauthor have retained the publishing rights, and arXiv would provide additional exposure for this information and proposals.  This is not the proper place for their detailed discussion, but I would like to hear your opinion or others who read these papers at the above links. For those who may be interested, respond at pantheory.org@gmail.com  and I will respond.

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  • 2 weeks later...

Dude, remember, science does not "prove."

 

Sure, but you know what I meant.  Is there anything science can hang it's hat on that explains "dark energy"?

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"Dark energy" is a hypothesis that explains the expansion of the universe. However, we are not able to fully elucidate this "mechanism." Our understanding very well may change and is far from "complete." Unfortunately, these questions really are outside of my field and any detailed dialogue would not be fruitful and could likely illuminate the full extent of my ignorance to folks who are echelons beyond me in terms of understanding and explaining the cosmos.

 

Edit:

 

If I may be allowed to go outside of my league, perhaps saying "dark energy" is a bit confusing and possibly not correct? From what I understand, several "mechanisms" can hypothetically explain our observations. As I understand, small "modifications" to the quantatitive framework of general relativity over large scales can work as well as other ideas such as a model that changes with time known as quintessence. There are other hypotheses but for now, as far as I know, we just do not know.

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