“Nothing exists except atoms and empty space; everything else is just opinion.” -Democritus of Abdera

When you take a look out at the Universe, past the objects in our own solar system, beyond the stars, dust and nebulae within our own galaxy, and out into the void of intergalactic space, what is it that you see?

FORS deep field

Image credit: BRI composite-image of the FORS Deep Field, ESO, VLT.

What we normally think of as the entire Universe, consisting of hundreds of billions of galaxies, with about 8,700 identified in the tiny patch of deep-sky shown above. Each one of those galaxies, itself, contains hundreds of billions of stars, just like our own Milky Way, and this is just counting the part of the Universe that’s presently observable to us, which is by no means the entire thing!

2dF Galaxy Redshift Survey

Image credit: 2-degree Field Galaxy Redshift Survey.

And yet, if we map out everything known in the Universe, and trace out the cosmic structure, we find that the normal matter — things made out of all the known elementary particles — is less than 5% of the total energy density of the Universe. There’s got to be about 20-25% of the Universe in the form of dark matter, a type of clumpy, collisionless matter that is made up of a yet-undiscovered particle, in order to get the type of clustering we see.

But perhaps most bizarrely, the remaining energy of the Universe, the stuff that’s required to bring us up to 100%, is energy that appears to be intrinsic to empty space itself: dark energy.

Energy density pie chart

Image credit: NASA, retrieved from http://universe-review.ca/.

So, as part of Matt Francis’ Carnival of Cosmology on Dark Energy, I’ve decided to answer your best questions on dark energy, and I promised I’d take all comers. Let’s see what we can learn!

Models of the Expanding Universe

Image credit: Large Synoptic Survey Telescope, NSF, DOE, and AURA.

Where is the dark energy coming from in an expanding universe? It seems to violate the laws of energy conservation. -Richard Latham

This question is a good one: if there’s an intrinsic energy to space, and it’s expanding (and therefore creating more space), aren’t we violating the conservation of energy? The answer is no, because dark energy doesn’t only have an energy density: it also has a negative pressure with very specific properties. As that negative pressure pushes outwards on space, it does negative work on the Universe, and the work it does is exactly equal to the increased mass/energy of whatever patch of space you’re looking at. I wrote a more technical explanation here last December, for those so inclined.

Fate of the Universe

Image credit: NASA / Chandra X-ray observatory.

In articles about the nature of dark energy, I frequently see “quintessence” mentioned as one possibility. I’ve never seen any explanation of what that would be. In my present state of knowledge, the word might as well be “magic”. Assuming it is legit (i.e. not a handwave or ether redux) can you give us some idea of what it is? -anatman

Let’s back up a little bit and explain “dark energy” first. When physicists say “dark energy,” we mean that we observe a uniform accelerated expansion to the Universe, and in physical cosmology the thing that causes that is a uniform energy density with a sufficiently negative pressure.

The simplest model that fits the data is to have dark energy be what Einstein called a cosmological constant, where the pressure is equal to the negative of the energy density times the speed-of-light squared [ P = – ρ c2 ], and that’s still 100% consistent with the best data we have today from all sources. But it could be something more complicated: dark energy could be time dependent, it could have the pressure not satisfy the above equation exactly, it could behave in any way other than this that you can imagine. A large class of the models we can imagine (parametrized by a scalar field, if you care for that detail) are known as quintessence.

They may be fun (for some) toys to play with, but there is so far no evidence to indicate that dark energy requires any more complexity than the simplest explanation: the cosmological constant.

Abstract artwork of subatomic dark particles

Image credit: Lynette Cook / Science Photo Library.

In your opinion, what length of timeframes and advances in technology do you relatively think it’ll take to understand dark energy beyond just observing its effect on the expantion of the universe? -James G.

Is there a known (or suspected by a theory) connection between dark energy and fundemental particles? -Erol Can Akbaba

Is there any plausible experimental handle on dark energy? Any reasonable way, either on the ground, or at least on Solar-system scales, to directly interact with whatever it is? -Michael Kelsey

That depends on whether dark energy is related to a particle or not. If it is, then all it will take is a powerful enough collider to create that particle, and a way to distinguish that missing energy from things like neutrinos.

If dark energy isn’t a particle, however — and since it doesn’t appear to interact, clump or cluster the way other particles do — our prospects are much more pessimistic. Which is to say, I can’t even imagine how to do it under those circumstances, given the physics that I currently know.

curvature of the Universe

Image credit: Shashi M. Kanbur at SUNY Oswego.

How does the previous post about a universe being so flat flat flat that there could be trillions of years of expansion enter into this? -Dave Dell

Curvature and energy density are very closely related in cosmology: you measure the expansion rate (which allows you to calculate the Universe’s critical density), you measure the energy density, and then you compare those two to determine the curvature. As far as our measurements can tell, the actual average energy density of the Universe — including dark energy — is indistinguishable from the critical density, and that’s why our Universe’s curvature is indistinguishable from flat.

WMAP sky map of the Cosmic Microwave Background

Image credit: WMAP Science Team / NASA.

Could Dark Energy be the final stage of light? I learned in High School (provided my memory serves me right) that as light travels and expands it moves further along the spectrum and that the universe is filled with Cosmic Microwave Background Radiation. Could Dark Energy be that radiation? -Jordan Brooke

I wish that were possible. Radiation — in this case, in the form of photons — is generically a massless particle that moves at the speed of light. Unfortunately, it’s incredibly well understood, it does contribute to the expansion rate of the Universe, but it slows the expansion down, and has a positive, not a negative pressure. So while it does exist and does contribute to the expansion rate, it is not the cause of dark energy.

On the other hand, dark energy actually causes the radiation to redshift faster than it would in a Universe without dark energy. So in our Universe, the presence of dark energy actually makes the cosmic microwave background radiation less important to the fate of the Universe than a Universe without it!

Image credit: NASA, STScI, Adam Riess, and the High-Z Supernova Search Team.

The reason I have a hard time accepting Dark Energy is because I have no idea what I’m even supposed to be thinking of. As anatman said, it seems like so much “Abra Kadabra!” and poof, an F appears on my physics test. -Donovan, seconded by Jeff

I once had a (very cranky) physicist describe dark energy as “The biggest F U the Universe could have possibly given us.” While I don’t quite agree, I do sympathize with that point of view. I think of it as a fluid that permeates throughout all of space with a positive energy density and a negative, outward-pushing pressure. That may be dissatisfying, but it’s what the math and physics tell us, and at this point, that’s the best I’ve got.

Pie chart of the Cosmological Composition

Pie chart of the Cosmological Composition, from the forums at BBC focus magazine.

Why is it called, dark ‘energy’? – Jeffrey Boser

The energy part doesn’t bother me nearly as much as the “dark” part does. The energy part is because it’s an intrinsic energy to space — the zero-point energy — that actually has a positive, non-zero value. I would prefer to call it “vacuum energy” because it’s the energy intrinsic to empty-space, or the quantum vacuum, but this dudesaid “dark energy” before anyone knew who I was and now everyone calls it that, and most of us hate the name, too. Bummer.

Newton's 3rd

Image credit: retrieved from http://rocketxtreme.wikispaces.com/.

If the universe is accelerating, where is the equal and opposite reaction? -Bobby van Deusen, for his 14-year-old son, Jack

The answer, believe it or not, is “dark energy.” The accelerated expansion of the Universe is the reaction, and dark energy is the thing that causes it, does the work on our spacetime and is the action. If the Universe either had dark energy and no acceleration, or had acceleration with no dark energy, then we’d have a problem. But we have one because we have the other, and in fact that’s how we know we have dark energy.

de Sitter spacetime

Image credit: John D. Norton from the University of Pittsburgh.

Is Dark Energy a fundamental force of nature? -Jon

As far as we can tell, it is not a separate force the way electromagnetism, the weak force, or the strong force is. It is part of the force of gravity, and was even predicted by general relativity originally. Gravity could have existed with zero dark energy, but that doesn’t appear to be the Universe we live in. Regardless, it isn’t an extra force, just one aspect of General Relativity that happens to exist the way it does.

The Luminiferous Aether

Image credit: Relativity Calculator.

Sounds like ether to me. -Alan

The big difference, remember, was that ether was a thing that light needed to travel through. With the exception of the expansion rate of the Universe, nothing we can measure would be any different if it weren’t for dark energy. While dark energy appears to have one thing in common with the old luminiferous aether — it permeates all of space, uniformly, everywhere — it neither has a preferred reference frame nor is it required as a medium for anything to travel through.

At least, as far as we know.

Abell 2151

Image credit: The Hercules Galaxy Cluster, by Russ Croman / RC Optical Systems.

Is this new dark energy being created that is strong enough to overcome gravity attraction between galaxies? -BillK

We live, right now, in either a very interesting or a very disgusting time, depending on your point of view. On one hand, gravity is still working in full-swing, and all masses are gravitationally attracted to all other masses in the Universe. On the other, there is this intrinsic dark energy “pushing” things that are expanding away from one another to accelerate away from one another even faster.

At this point in time, everything that is already gravitationally bound to one another — including us and our local group, and all the individual galaxies in a large cluster (like Hercules, above) — will stay that way; dark energy will lose to gravitation on those scales. But on larger scales, those groups and clusters that are not already bound to one another never will become so, and will accelerate away from one another as the Universe continues to expand.

Bell curve

Image credit: .

My question is basically why the need for DE? The whole universe can still be homogeneus and isotropic on the largest scale but have fluctuations on small scales. -Sinisa Lazarek

If what we observed as “dark energy” were just a fluctuation — a result of our observable Universe being a different density than most of the Universe — we would be about a 10,000-sigma fluctuation away from what we’d normally expect. The probability of that happening is about the same as your odds of playing “1, 2, 3, 4, 5, 6″ and winning the lottery every week in a row for your entire life.

In other words, it’s unlikely enough that we don’t even consider that as a reasonable possibility.

And finally, one last one…

Hubble Ultra Deep Field

Image credit: NASA, ESA, R. Windhorst and H. Yan.

Why should I care whether Dark Energy exists or whether it’s just an intellectual exercise????? aka ‘What’s in it for me?’ -Norma Parfit

See all those things in the night sky? Everything out beyond the stars in our own galaxy? In a few billion years, we’ll merge together with Andromeda, the only other large galaxy in our local group, and our combined, giant elliptical galaxy will eventually gobble up the remaining dwarf galaxies orbiting us, and then all we’ll have beyond our own galaxy is this: the intergalactic void.

Because thanks to dark energy, all of this — every other galaxy, group, cluster, and supercluster of galaxies — will disappear from our observable Universe. What’s in it for you? The opportunity to know the Universe, as it is right now, and as it won’t be in a trillion years.

In fact, if humans came on the scene, for the first time, a trillion years from now, we never would have learned about the cosmic microwave background, about distant galaxies, clusters, or have seen a single “spiral nebula” in the night sky. Because dark energy is going to accelerate that all away. Even the Virgo cluster, the closest large collection of galaxies to us, will disappear from view.

Virgo Cluster

Image credit: Randy Brewer.

And if that doesn’t make you care, I don’t know what will. Even though I wish we understood its nature better, this is our Universe, full of dark energy, as we know it today. Enjoy it while it lasts, because it only gets lonelier from here!

Comments

  1. #1 James MacAulay
    Toronto
    July 26, 2012

    About the incredibly low odds of dark energy being a local fluctuation: what about the anthropic principle? If some other region of the universe had a wildly different density, what consequences would that have for the prospects of life there?

    I’m imagining our observable universe as a dense expanding pimple in the middle of much vaster emptiness (or if that’s not a uniform-enough universe for good taste, maybe an expanse of hills and valleys of density). In such a universe, of course we’d be in a dense part because that’s the only sort of place we could have evolved.

    I guess we’re just pretty sure that a lack of dark energy wouldn’t make it any harder for life to evolve?

  2. #2 Corey
    July 26, 2012

    So, on rereading the December 2011 post on dark energy, I found clicked through to the post on Cosmic Variance which notes that energy is not conserved in GR — instead there is “energy-momentum conservation”. I know that in Newtonian physics, energy conservation corresponds to time-translation invariance of the laws of motion by Noether’s theorem (not that I’m very familiar with Noether’s theorem, but I know *of* it). Is there a similar invariance in GR that corresponds to energy-momentum conservation?

  3. #3 Wow
    July 27, 2012

    James, that wildly different area would have demonstrated a different density, therefore we have no need to assume it has a similar density to our local area.

    It’s just without cause otherwise, we have to assume a similar scenario as we observe here would be observed everywhere.

    Without that assumption, we could infer no universal laws, only local specifics, and we would not have a clue about the effects that make it appear gravity, for example, depends on mass concentration only. We could only say it depends on that on earth, but on the moon, without an atmosphere, it may not, since we haven’t stripped off earths atmosphere to see if that changes things here.

  4. #4 Chelle
    July 27, 2012

    ” I think of it as a fluid that permeates throughout all of space with a positive energy density and a negative, outward-pushing pressure.”

    I appreciate this answer, thanks.

  5. #5 Tony Mach
    July 27, 2012

    You keep using that diagram were the “23% dark matter” slice is way bigger than a quarter:
    http://scienceblogs.com/startswithabang/files/2012/07/I02-13-composition21.jpeg

  6. #6 Tony Mach
    July 27, 2012

    Besides, the labeling of the other graph you use is less confusing with regards to “free” and “non-free”:
    http://scienceblogs.com/startswithabang/files/2012/07/800px-Cosmological_Composition_-_Pie_Chart.png

  7. #7 Scott
    July 27, 2012

    Dark energy permeates the void evenly. So does the Higgs field. Is the Higgs field dark energy? Are ther speculations among physicists, or ideas about how we might determine if Higgs is the dark energy?

  8. #8 OKThen
    Planet Earth
    July 27, 2012

    Great answers Ethan. Thanks.

    Ethan, you say, “dark energy doesn’t only have an energy density: it also has a negative pressure.. that negative pressure pushes outwards on space, it does negative work on the Universe.” I think I understand.

    Now considering a black hole, it also has an energy density; but if “negative pressure pushes outward on space” then a black holes swallowingness would seem to have a “positive pressure that pulls inward on space” and thus a black hole would do positive work on the universe. Am I misunderstanding, or is this correct?

    Assuming my conclusion is correct; is there possibly a cosmic cycle that involves
    1) continuous “negative work on the Universe” caused by the vacuum energy (aka Dark energy/cosmological constant)
    2) continuous positive work on the Universe caused by the many black holes at the center of galaxies.
    3) and since 1) is correct and if 2) is correct; is it possible that 1) and 2) are balance (e.g. according to QM and GR)?

    That’s the question that crosses my mind. Any responses and insights will be appreciated.

  9. #9 Wow
    July 27, 2012

    I don’t think Ethan is right with

    “it also has a negative pressure.. that negative pressure pushes outwards on space, it does negative work on the Universe.”

    Because positive pressure pushes outwards on space. And therefore “does negative work on the universe”.

    It’s antigravity, in that it is infinite ranged like gravity or electromagnetism, doesn’t have charge dependency like electromagnetism, but is a universally NEGATIVE force, unlike the POSITIVE force of gravity.

  10. #10 Denier
    July 27, 2012

    @Wow

    Although it seems backwards, Ethan is right. Negative pressure pushes outwards on space. Think of space like a bed sheet pulled tight. Putting a bowling ball on it puts positive pressure on it. Any marbles you dropped on the sheet would accelerate towards the bowling ball in the middle. Dark Energy is a negative pressure that creates a convex curvature so marbles would accelerate towards the edges.

    Mathematically, the effect of pressure on curvature is described in the Friedmann equasions.
    http://en.wikipedia.org/wiki/Friedmann_equations

  11. #11 Wow
    July 27, 2012

    “Think of space like a bed sheet pulled tight.”

    No. Why should I?

    If I have some parcel of air at high pressure in a container and I relax that container’s rigidity so it can expand or contract freely, what happens to the air container? What happens to the air that surrounds it?

    The air parcel expands.

    This despite there being no negative pressure, only positive.

  12. #12 Ethan
    July 27, 2012

    Wow,

    It is totally understandable, what you’re saying about pressure. This is, after all, how pressure affects matter: a high pressure area pushes out against the lower pressure regions, while a low (relatively negative) pressure area pulls in on its surroundings.

    But that is now how the Universe’s curvature responds. Positive pressure contributes the same way that positive energy density does: more of it means that there’s more “stuff” pulling on spacetime, fighting the expansion. Less of it (more negative stuff) means there’s a push on spacetime, enhancing the expansion.

    In GR, the contribution to the total acceleration is the energy density plus *three times* the pressure (one each for all three spatial dimensions). So overall, dark energy contributes negatively (because +1 -3 = -2), and that’s why it causes an overall acceleration, doing negative work on the Universe.

    Sorry for the technical explanation.

  13. #13 Wow
    July 27, 2012

    If you use analogies to describe a subject qualitatively, you must use those analogies consistently.

    If you wish to show the Freidman equations that have a negative response to pressure (because it is a potential energy repository and E=mc^2, therefore to redress this hidden potential, the reaction has to be negative on either the explicit energy (kinetic or photon for example) or the implicit energy (binding or potential)), then you must use the friedmann equations with its use of energy inclusion of both explicit and implicit energy.

    Positive pressure pushes the surrounds back.

    Therefore the use of negative pressure and say that this is used because it pushes back the surrounds is counter to the analogy of pressure.

    Really we’re talking about the missing energy that an implicit energy store retains.

    Dark Energy is implicit energy (we can’t withdraw it), but acts to expand the universe (like explicit energy does).

  14. #14 Wow
    July 27, 2012

    Ethan, I hope that the follow on post helps show why I counter this use.

    If you used energy rather than a loaded everyday term like “pressure”, then it would be a lot clearer without the conflating baggage.

    We’re quite used to different forms of energy.

    Different forms of pressure? Not so much.

    The confusion doesn’t exist in the mathematics, but this forum has very few people who could follow the necessary maths, hence using the specific terms that make sense there isn’t useful here (I could, with some long lead-in time and a bit of help remembering, get to understand the maths, but I’m basically lazy…)

  15. #15 Torbjörn Larsson, OM
    July 27, 2012

    Interesting reflections.

    Where is the dark energy coming from in an expanding universe? It seems to violate the laws of energy conservation. -Richard Latham

    I never understood why this would be seen as a more problematic question than the question of how existing space grows into a larger volume of existing space.

    The solution is the same of course, as long as locally flat space or dark energy balance or the universe seen as a system convinces us that there is no input of energy required.

    If dark energy isn’t a particle, however — and since it doesn’t appear to interact, clump or cluster the way other particles do — our prospects are much more pessimistic. Which is to say, I can’t even imagine how to do it under those circumstances, given the physics that I currently know.

    I don’t think that is correct. Weinberg gave a very early prediction for the cosmological constant by using anthropic theory. I think that is alive and well, look at Susskind’s latest arxiv paper on eternal inflation.

    At least as long as the Planck probe results promised later this year haven’t sunk eternal inflation…

    I would prefer to call it “vacuum energy” because it’s the energy intrinsic to empty-space, or the quantum vacuum, but this dudesaid “dark energy” before anyone knew who I was and now everyone calls it that, and most of us hate the name, too. Bummer.

    Yeah, well, the predictions that it is a cosmological constant and that that constant comes out of vacuum energy is auxiliary, no?

    But it would have been nice!

    If what we observed as “dark energy” were just a fluctuation — a result of our observable Universe being a different density than most of the Universe — we would be about a 10,000-sigma fluctuation away from what we’d normally expect.

    Uups! I have to be careful now. Ever since Theobald managed to estimate the probability of a UCA as ~ 10^2000 larger than separate cellular ancestors, I have maintained that is the best observation in all of science and the best we can expect.

    Of course, all that builds on combinatorics on speciation phylogenies, which is why I expect it to remain the best observation ever. A direct comparison with a random null hypothesis would be the creationist independent ‘poofing’ of all species.

    Today’s species are estimated @ ~ 10 – 100 million. [Global biodiversity, Wikipedia]. I hear fossils predict ~ 99.9 % of all species has gone extinct. So conservatively we have the likelihood for independent species of ~ 2^(10^7*10^3) ~ 10^10^9. On a gaussian approximation of the large binomial distribution the LUCA is ~ 10^4 times as likely as dark energy.

    Phew! I feel better now.

  16. #16 Torbjörn Larsson, OM
    July 27, 2012

    @ James MacAulay:

    I can’t say I understand the cosmology, but a complete lack of vacuum energy would be unlikely AFAIU. I hear that in multiverses/string theory vacuum energy can go all the way down to slightly negative energy, which is an uninhabitable end state of multiverses AFAIK. (No matter, I think.)

    @ Corey:

    I can’t say I understand general relativity (this is a theme!), but several energy principles exist in GR AFAIU. I hear there is a lack of global energy principle which would correspond to Noether’s energy-time I think, as that derives from a global symmetry as I understand it (no Noether either :-/). The reason redshift violates energy conservation is because you look over cosmological volumes that expand, not a closed system.

    I hear at least one of the local energy principles correspond to flat space zero energy. But there is a way to assess global energy by looking at the system behavior of a cosmology, GR and global solutions and all. Then it turns out universes are thermodynamically closed systems with an attractor that asymptotes to zero energy. “One might question the notion that an infinite spacetime filled with matter should have zero energy. The instinctive answer might be that the energy is infinite. However, the open FRW universe dilutes its matter density to an infinite extent and is hence asymptotic to Minkowski spacetime.”

    ["ON THE TOTAL ENERGY OF OPEN FRIEDMANN-ROBERTSON-WALKER UNIVERSES", Faraoni et al, Astrophys. Jour. 2003.]

    Of course it is arguable. You can look up “Zero-energy universe” in Wikipedia.

    @ Scott:

    A similar but simpler idea was that the scalar Higgs field could be a field of inflation. Seems it didn’t work with the current parameters for the Higgs.

    Not a definitive analysis, I’ll give you that. =D

    @ Wow:

    Matthew Francis post explains this.

    “Why dark energy is weird. The top two pictures shows how normal gases behave: in a small volume, the gas is compressed and can support a large weight, while if the gas expands, its pressure decreases. The bottom two pictures show what happens if you could somehow confine dark energy: the smaller the volume, the smaller the pressure, while a large volume has a larger pressure.”

    In GR, energy have pressure AFAIU i.e. it isn’t an analogy as you claim, and Francis goes through some of that too.

  17. #17 Torbjörn Larsson, OM
    July 27, 2012

    I must be tired. The LUCA may be ~10^10^8 times as likely as the DE observation. Well, it is enough that it is “a huge factor”.

  18. #18 Wow
    July 27, 2012

    You may be right there torbjorn, but pressure is used with the “pushes back the surrounding space” which doesn’t talk about the effect on the pressure (in your case, increasing) whic DOES support the meme of “negative pressure”. But pushing back the surround? Normal positive pressure does that.

    Meanwhile, negative gravity WOULD cause everything else to repulse.

    Appropriate analogy accorded to appropriate phenomena.

    Physics is easily confusing as it is, lets not increase the opportunity for it, hmm?

    Ta.

  19. #19 Jon
    July 27, 2012

    Hey! Thanks for answering my question!

  20. #20 Alexander Wolfe
    Dallas, TX
    July 27, 2012

    Ethan, what is the time frame for the Big Rip? I saw your mention of a trillion years, but when I did some Googling I ran across pages asserting that it could happen as little as 60 billion years from now, or even less. Do we have a commonly accepted answer for how far in the future the rip is, and how confident are we of that figure?

  21. #21 Ethan
    July 27, 2012

    Wow,

    Pressure is what it’s been called since long before I came on the scene. It predated Einstein and, as far as I know, goes all the way back to Euler. It might not be intuitive because it doesn’t behave the same way towards curvature as it does towards matter, but it’s the only thing to call it.

    Jon,

    You’re welcome.

    Alexander,

    That would depend on how different from a cosmological constant it is. Remember I said P = – ρ c^2 for a cosmological constant? We can put a letter, w, in there instead, so that P = w ρ c^2 instead.

    If w < -1, we get a big rip. Right now, it’s constrained that w = -1.0 +/- about 0.18, and that will continue to improve over time. A trillion years is about as long as it will take for the closest unbound galaxies to disappear completely from our night sky in the case of a cosmological constant, but a Big Rip could, with the current constraints, happen as “early” as about 80 billion years from now.

    See the excellent post from astrokatie (linked under my name) for a deeper discussion of the Big Rip and timescales.

  22. #22 Shane Stanton
    Australia
    July 27, 2012

    Thank you Ethan – very interesting.

    I was meaning to ask a question as well – “if DE is adding more space between us and distant galaxies, and a galaxy is said to be 1 billion light years from us, does that mean that the galaxy: (a) was 1b LYs away when the light left it (in which case it is >1b LYs away now); (b) was <1b LYs away when the light left but exactly 1b LYs now; (c) was 1b LYs now such that the light took exactly 1b years in transit; or (d) something altogether?”

    Thank you and apologies if this is a dumb question.
    Shane

  23. #23 Bill Lee
    Canada
    July 27, 2012

    Wonderful, informative blog, Ethan. I learned a lot which I like, and I didn’t understand bits which I also like ’cause it stretches my brain. :-D

  24. #24 OKThen
    Testing OK
    July 29, 2012

    No time now. I have to read carefully what Ethan said and Wow and the missing link. And digest it.

  25. #25 Sinisa Lazarek
    July 29, 2012

    Ethan, thanks for taking the time to answer my question. Much appreciated. Best regards.

  26. #26 Patrick M. Dennis
    July 29, 2012

    Ethan — In the comments thread that emanated from your December, 2011, post on Dark Energy, you promised us a column “next week” on this question of pressure. Judging by the current thread as well as those in December, it may be time for that column!

  27. #27 OKThen
    My question again
    July 29, 2012

    Ethan, Wow and Torbjörn
    You seem to know what you are talking about. And I admit to my ignorance. I’ve read what you’ve said, followed links and done a few searches.

    But I have no idea if my question has been answered or ignored by any of you.
    Please don’t worry about being polite. If my question is stupid just tell me that and why as best you can. If my question is sensible but too difficult to even guess an answer (you know infinities everywhere) then tell no one can answer my question yet but we guess it is worn because of this or that.

    So if someone can give me a clue, an imperfect answer; I’d appreciate it.

    So let me paraphrase my question and thought process (same idea as above)
    1) negative pressure means the universe is inflating (i.e. like a balloon)
    2) black holes are kind of deflating (i.e. really sucking) so do they have positive pressure (I think so)
    3) There are 170 billion galaxies in the observable universe. so there are a lot of supermassive black holes at the center of each of those galaxies. So that’s a lot of real sucking, i.e. deflating, i.e. positive pressure.

    So we got a balloon universe being blown up everywhere inflation (i.e.cosmological constant or such) but we got 170 billion black hole leaks in the balloon (i.e. deflating the universe).

    So maybe despite the eternal inflation (maybe I use this term incorrectly); maybe the persistent 170 billion black hole positive pressure leaks will leave the universe essentially looking the same in 1 trillion years. Now this is a very dynamic looking the same; and I suppose it may require maybe extra dimensions, curved space (at least in the vicinity of the black hole).

    So please tell me why my thinking is wrong or what nonsense would be required for it to be possibly correct; give me an idea. I don’t want to argue my point; I want to understand what is wrong or problematic or naive with my thinking.

    Teach me something please. thanks.

  28. #28 Sinisa Lazarek
    July 30, 2012

    @OKThen

    no physicist, but think you are mixing the two different things, black holes and DE. Black holes suck in matter, they don’t suck in space. Yes, they curve space a lot (maybe to singularity), but they don’t suck space out of existance. Black holes are not “deflating” the universe. Space is still there.

  29. #29 Sinisa Lazarek
    July 30, 2012

    p.s. if your scenario was the case, then you have to account that everything with mass will “suck in” space.. the Earth, the Sun etc.. Earth and Moon would colapse onto one another, the black holes would suck the space of every galaxy long before we came on the stage… etc..

    None of that happened/happens… so…

  30. #30 Wow
    July 30, 2012

    “Black holes suck in matter”

    I know what you mean, but: AAAARRRGGGHHHH!!!!!!

    Black holes no more suck in matter than the earth does (when asteroids or meteoroids fall in to the earth’s gravitational field and smack into the ground…).

    Ethan (and for some reason trying to answer on a tablet only ever seemed to click the link, so only answering now), you don’t seem to be getting my point.

    Pressure, like temperature or entropy or many many other things from classical mechanics are not real things in themselves. No atom has “pressure”.

    The maths uses this because this is the terms that we can use and measure (or attempt to), as opposed to using more physically real but insanely complex to measure items like velocity and vectors of each atom).

    Besides that, your use here:

    “it also has a negative pressure with very specific properties. As that negative pressure pushes outwards on space, it does negative work on the Universe”

    Positive pressure pushes outwards.

    Yours is more correct if you use “pressure” (as opposed to “energy” or “momentum” or “temperature” or similar) in the maths, but for people not into the maths, this is confusing because your assertion of special properties appears to be the property of the non-special version too.

    After digging into the maths, you can see why it’s genuinely special, but not from what you do there.

  31. #31 Sinisa Lazarek
    July 30, 2012

    @ Wow

    sorry for “suck”.. gravitate is the appropriate word, but it’s what OKThen used in his question/post, so I used it in the same way.

    He said: ” So that’s a lot of real sucking, i.e. deflating, i.e. positive pressure.”

    don’t get angry instantly :)

  32. #32 OKThen
    A learning place
    July 30, 2012

    I am not trying to argue to win, I’m discussing to learn.

    Sinisa, you say, “Black holes are not “deflating” the universe.”

    Well I’m not sure; not because I am right; but because I don’t know. Let me be clear;what I am trying to do here is to understand current theory (I assume some form of inflation or eternal inflation i.e. or e.g. Alan Guth). I am not trying to propose a new theory; so if Wow or Ethan tell me, No, no. My only argument will be can you explain that a little better to an inquisative person. And an imperfect answer especially in laymen’s terms) is OK; as well point me to a path of learning that will take me years (e.g. read these 2 books and 10 papers)

    So with that disclaimer,
    1) “cosmic inflation, cosmological inflation or just inflation is the theorized extremely rapid exponential expansion of the EARLY UNIVERSE by a factor of at least 10^78 in volume, driven by a negative-pressure vacuum energy density.” wiki
    2) “dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe… The data confirmed cosmic acceleration up to half of the age of the universe (7 billion years), and constrain its inhomogeneity to 1 part in 10.” wiki So, dark energy acts on the current universe; and I will not argue with the data.

    Now when we say that “constrain (the universes) inhomogeneity to 1 part in 10″; I think we are refering to the vast expanses of empty space (in particular the voids between galaxies and clusters of galaxies). No one argue that spacetime is homogeneous in the vicinity of matter (i.e. a planet, star or blackhole).

    In particular, a black hole curves spacetime too the extreme; but in the opposite manner that the big bang curves spacetime and also in the opposite manner that cosmic inflation (of the early universe) and also in the opposite way that dark energy (e.g. maybe Guth’s eternal inflation) continuously curves space time.

    So whether I talk in metaphor or in “The maths (that) uses.. more physically real but insanely complex to measure items like velocity and vectors of each atom”; it seems to me that the “velocities and vectors” on each atom and elementary particle and every virtual particle depend upon the location of these various particles.

    Now to be sure, in the vastness of cosmic voids, the “velocities and vectors” determined from the movement of galaxies (i.e. redshift data) suggests that spacetime of the universe (as a total) is behaving a certain way (i.e accelerated iexpansion, i.e. dark energy).

    But spacetime as a local phenomenon is everywhere flat (i.e. inertial frame of reference/equivalence principle).
    But when in dark energy scenario, we say universe is inflating; we are not looking locally and summing over elementary particles, etc everywhere; because we don’t know what to do with the infinities (i.e. the infinite spacetime inhomogeneity) inside the event horizon of a black hole.

    So I assume current math physics techniques just throw away the spacetime infinities inside a black hole as not significant. I mean what do you do with an energy density (ie.energy momentum tensor) that reaches infinity.

    I assume that math physics throws away these supermassive black hole terms with reasoning like this. A galaxy contians 100s of billions of stars; the supermassive black hole has the mass of only 100s of million of stars. Thus throwing away 1/1000 th of the stars should be OK.

    But I am asking, “Is it possible that this 1/1000 th of baryonic mass (i.e. supermassive black hole mass) of the universe (in the form of 170 billion supermassive black holes) somehow balance the spacetime general relativity curvature.

    Now we know that locally everywhere in the universe (according to general relativity) that spacetime is flat in the local inertial frame of reference (i.e. equivalence principle.

    So reframing my question; is local flat GR inertial spacetime indifferent to whether cosmic spacetime inflates; while black hole spacetime deflates. Or if all the local spacetimes are summed from any particular (e.g. Earth or nearby Earth) must all of the spacetime (whatevers energy momentum tensors and such). When all of such quantities are summed over the whole universe including black hole singularities does general relativity say maybe these black hole singularities are infinite leaks in the spacetime balloon that perfectly balance the inflation of the whole baloon. all of this of course done from a particular inertial reference.

    And yadda yadda yadda; I understand there are hundreds of possible model universes and all of these make many many assumptions. so I guess my question is what is my question implicitly or explicitly assuming that usually is thought to be unreasonable or completely wrong.

    I will say no more, except maybe thank you.
    Please give me your best informed wackiest or non wacky thought.

  33. #33 OKThen
    Oops
    July 30, 2012

    Oops error.
    I meant to say, ” No one argue that spacetime is inhomogeneous in the vicinity of matter (i.e. a planet, star or blackhole) and extremely inhomogenousinside the event horizon of a black hole”.

  34. #34 Wow
    July 30, 2012

    “don’t get angry instantly”

    AH HA!

    Got you!

    There’s no such thing as instant! The quickest possible event occupies at least the planck time, therefore there is no instantly!

    :-)

  35. #35 Wow
    July 30, 2012

    “1) “cosmic inflation, cosmological inflation or just inflation is the theorized extremely rapid exponential expansion of the EARLY UNIVERSE by a factor of at least 10^78 in volume, driven by a negative-pressure vacuum energy density.” wiki”

    At this level, it’s probably better to call the expansion as driven by the phase change from one type of “space” (one where, for example, photons and matter are bound together) to another (one where, as today, photons travel mostly freely through space, uncoupled).

    Like the energy released from a phase change of water to ice. Or steam to water.

    That doesn’t make it kind of a dark energy, though.

    “But spacetime as a local phenomenon is everywhere flat (i.e. inertial frame of reference/equivalence principle).”

    Read up on “Mincowski spacetime”. Assuming locally flat is a simplification. We have computing and mathematical shortcuts that reduce the need for such simplification.

    It’s very hard to find a place in the universe that is properly inertial.

    “I mean what do you do with an energy density (ie.energy momentum tensor) that reaches infinity.”

    You change your geometrical measure. I.e. you don’t use cartesian geometry on a spherical earth over a scale of 1000miles. You use spherical geometry.

    Similarly, if you use time as an imaginary coordinate, you no longer get a big bang, spacetime becomes a sphere. The “North Pole” being the big bang, the “South Pole” a big crunch. But you no longer have infinities.

    You’d do the same thing inside a black hole’s event horizon.

    From an observer in there, you STILL get expansion of spacetime. Hubble constant still makes things retreat, and expansion makes the Hubble constant increase over time. And at some time you get your destination (the centre of the black hole’s gravitational well) retreating, since it too is distant from you, and at some distant future, that black hole is beyond the visible horizon, retreating faster than light.

    Remember, from the frame of reference of someone inside a black hole, they continue to accelerate toward that centre. And there is still distance to go to get there.

    It gets seriously weird.

  36. #36 Sinisa Lazarek
    July 30, 2012

    @ OKThen

    not arguing of course, we are all here to learn. So this would be my reply. Again, not saying I’m right, just my take on it.

    Correct me if I’m wrong, but seems to me that there are two parts to your proposal. First is some link between inflation and expansion (DE) and second part deals with curvatures of spacetime.

    So as for first part, I don’t know if those two (inflation and DE) can be taken as a same thing, or a manifestation of the same force. It might be, but I just don;t know. My educated guess is no. Inflation (at least Gut’s) happens “before” what we think of as big bang. In eternal inflation model it produces multiverses and other weird things which are not related to this topic since we are dealing with “our” bubble universe.

    In the second part, I think you made one error in reading. I quote you:

    ” The data confirmed cosmic acceleration up to half of the age of the universe (7 billion years), and constrain its inhomogeneity to 1 part in 10.” wiki So, dark energy acts on the current universe; and I will not argue with the data.

    Now when we say that “constrain (the universes) inhomogeneity to 1 part in 10″; I think we are refering to the vast expanses of empty space (in particular the voids between galaxies and clusters of galaxies). No one argue that spacetime is homogeneous in the vicinity of matter (i.e. a planet, star or blackhole).”

    Notice in the first part it deals with inhomogeneity of acceleration. And in the second part you seem to talk about inhomogeneity of spacetime and later with curvatures. Those are not the same. First part only says that basically expansion is uniform from our perspective. It doesn’t deal with empty space and curvatures. It’s not the same thing.

    “In particular, a black hole curves spacetime too the extreme; but in the opposite manner that the big bang curves spacetime and also in the opposite manner that cosmic inflation (of the early universe) and also in the opposite way that dark energy (e.g. maybe Guth’s eternal inflation) continuously curves space time.”

    again.. I think you are trying to put 3 different things under the same force. I don’t think this works. In the current “theory” of DE, if we can call it that, yes, the positive curvature that DE imparts to spacetime causes it to expand. But by your rationale, we need to modify GR with a new term that addresses “contraction” of space due to mass imparting it with negative curvature. I am not one of those who says that changing GR is blasphemy. Just pointing out, that if you are correct, GR is not.

    But if this was in fact the case, we would have observational data of it. It needn’t be black holes. Every mass curves space. We would notice a discrepancy between observation and prediction. Ever so slight but we would notice. Every mass would in addition to curving spacetime also contract it. And like I said before, given the time, every gravitational source would “eat away” at spacetime. I don’t see this happening.

    the last part..

    “Now we know that locally everywhere in the universe (according to general relativity) that spacetime is flat in the local inertial frame of reference (i.e. equivalence principle.

    So reframing my question; is local flat GR inertial spacetime indifferent to whether cosmic spacetime inflates;”

    I am not sure if you are talking about geometry or topology of local spacetime when you say it’s flat. Every mass will curve spacetime in proportion to it’s amount. Be it a single atom or a star or a black hole. No exclusions.

    Then again you put in inflation in all this. By all theories inflation is not happening any more inside our universe. In eternal inflation model, the inflation is happening, but outside of our bubble universe. Every bubble universe is sort of a “break” in inflation, altough the model allows new universes to be created even inside an existing ones etc.

    But my bottom line is whatever model of inflation you take, it’s not the same as DE. As far as out bubble universe is conserned inflation stopped 13.8 billion years ago. Acceleration and expansion are happening, but inflation no.

    looking forward to your ideas :)

  37. #37 Chris
    July 30, 2012

    If the universe is expanding yet the molecules in my body stay roughly the same distance apart from each other, then this must mean that the atoms in my body are constantly countering this expansive force just to stay at this same distance? Not sure what my point is.

  38. #38 Wow
    July 30, 2012

    The point is that if your body was extended over 100,000 light years, you may be able to notice a difference in your entire body size changing.

    Over the length of 6ft and 100 years, not so much.

  39. #39 OKThen
    Thanks
    July 30, 2012

    Wow
    I must say your explanation is makes a lot of sense and cuts right through several of my confused ideas. That’s what I wanted; thanks for these insights that are new to me. In my opinion; you’ve broken my naive idea. Perhaps I see the problem with the pressure analogy. So I’ve got to learn more; I’ll follow your suggestion and focus on understanding Minkowski spacetime.

    Your comment “Similarly, if you use time as an imaginary coordinate, you no longer get a big bang, spacetime becomes a sphere.” makes sense to me. I need to follow up and understand more before I ask another question.

    Yes. So I defer to Wow’s explanation.

    Sinisa
    Thanks and yes I am confused. And I need to reread your thoughts. But I have no more ideas here now. My ideas are learning ideas. When someone like Wow shows me the naivetee of my learning ideas or breaks them; I’m very happy to learn that lesson.

  40. #40 Chris
    July 30, 2012

    “The point is that if your body was extended over 100,000 light years, you may be able to notice a difference in your entire body size changing.”

    Would it though? Wouldn’t the nuclear forces holding my molecules together ensure that the distance between the atoms remained the same?

  41. #41 Sinisa Lazarek
    July 30, 2012

    @ Chris

    the expansion is extremely tiny when viewed from our prespective of size.

    the expansion rate is about 74 km/s/megaparsec. And parcec is roughly 3 million light years. and a light year is about 9×10^12 km. So that’s 74km/s for every 27×10^18 kilometers. That’s so small that when scaled to our body size is incomprehensible. Let alone on atomic scale. The nuclear forces are much much stronger than DE’s influence.

  42. #42 Wow
    July 30, 2012

    Yes it would, chris.

  43. #43 Richard Jowsey
    New Zealand
    July 30, 2012

    @Wow “Similarly, if you use time as an imaginary coordinate, you no longer get a big bang, spacetime becomes a sphere. The “North Pole” being the big bang, the “South Pole” a big crunch. But you no longer have infinities. You’d do the same thing inside a black hole’s event horizon.”

    Instead of a big crunch (at the “end of time”), perhaps each of those billions of black holes could behave as a “south pole” of the imaginary time (complex) dimension.

  44. #44 Waydude
    July 30, 2012

    All this talk of ‘pressure’ being negative or positive had me laughing, sometimes I get into arguments with other pilots about whether if you have a decompression event, do you get sucked out or blown out?

    Semantics is fun!

  45. #45 Wow
    July 31, 2012

    Well, in this case, pressure isn’t what is causing the effect. The differing velocities mean that the air inside leaves faster than airreturns.

    Pressure is a good concept, but questions like that show that it, too, is an analogy.

  46. #46 Wow
    July 31, 2012

    Richard, I don’t know the maths, but I believe the pshere is a result of a closed universe.

    For me, the result was interesting as illustration of how you can re-phrase your questio or model to remove difficult issues.

  47. #47 OKThen
    July 31, 2012

    Richard
    Let me try to answer your question (which was mine as well).

    In my mind, Wow has correctly explained how in spherical co-ordinates (I assume 4-Dimensional with 3-spatial with real numbers and 1-temporal with imaginary numbers) that the big bang is not a singularity (but something similar to a pole on a sphere i.e. a North Pole). Well enough. And in that regard, a big crunch would also be something like a pole on a sphere (i.e. a South Pole).

    And to my mind, a black hole in such spherical type coorrdinates would also be like a little-south pole on such a sphere. But as Wow pointed out:
    “From an observer in there (inside the event horizon of a black hole), you STILL get expansion of spacetime. Hubble constant still makes things retreat, and expansion makes the Hubble constant increase over time.” Ouch, I had misunderstood this important point. What this means:

    I think, is that regardless of the little-south-pole ness (i.e. suckiness of a black hole); within the event horizons of these black holes we would still observe the accelerated expansion of our visible universe. So the suckiness (i.e. the deflationaryness, little-south-poleness of a black hole) is a very individual and very local effect. Sooo local that right up to the singularity of a black hole (or in spherical coordinates, right up to the little-south-poleness of a black hole) the universe as observed by measurements of redshifts of visible stars and galaxies is still in a state of accellerated expansion (i.e. inflation); i.e. dark energy is observed. OUCH! OUCH!

    That’s my understanding of the implication of what Wow explained. So until someone else who understands the math or until I can do the math (well enough) to explain differently; this is the geometric/physical picture that I am stuck with. OUCH!

    I don’t like it; but that’s what the data (and theory of general relativity) tells me; because as Wow correctly points out: Inside the event horizon of a black hole that data would be the same!

    OUCH! So much for my idea of popping the inflating balloon of our universe with a 100 billion little black hole singularity deflating pins. Yes they are still pins but they do not change the observed cosmic dynamic of dark energy observation even when viewed inside the event horizon of a black hole.

    So
    1) I will not argue with observation/experimental evidence.
    2) I’ve confined my understanding to interpreting general relativity; I am not trying to invent a new theory.
    3) sticking with observation and sticking with general relativity; I am stuck with a cosmological constant, dark energy, eternal inflation or something like that.
    4) Why OUCH!? Because it’s not philosophically what I prefer; but it is scientifically what I must accept based on the data and correctly interpreting general relativity inside the event horizon of a black hole.

    Thanks again Wow for popping my idea bubble. I mean if I am going to have an alternative idea; it needs to fit with data and current theory OR it needs to fit with data and a NEW theory or a NEW interpretation of old theory. And I got nothing NEW.

    I defer to Wow; when he understands something he explains it well; and when he doesn’t, he says he doesn’t know.

    On with my learning and questioning.

  48. #48 Wow
    July 31, 2012

    I never really got the hang of matrix operations in maths which meant in a lot of uni science I had to try and make up the marks in understanding better the handy-wavey bits.

    Finding the right handy-wavey-words isn’t much easier than matrix operations, however.

    Ah well. You do the best you can.

  49. #49 Shane Stanton
    Australia
    August 1, 2012

    There was a typo in option (c) in my earlier posted question which I have corrected here: “if DE is adding more space between us and distant galaxies, and a galaxy is said to be 1 billion light years from us, does that mean that the galaxy: (a) was 1b LYs away when the light left it (in which case it is >1b LYs away now); (b) was <1b LYs away when the light left but exactly 1b LYs now; (c) was 1b LYs now such that the light took exactly 1b years in transit; or (d) something altogether?”

    Any thoughts/responses would be most appreciated, and apologies again if this is a dumb question (if it is I am happy for someone to tell me as much….)
    Thank you,
    Shane

  50. #50 Sinisa Lazarek
    August 1, 2012

    @Shane

    Your question is not dumb, far from it. But the answer is not simple, since there are different measures of distance in cosmology.

    When you say i.e. that a galaxy is 1 billion years from us, and you want to be really precise, you need to say by which distance you mean it.

    There is “proper distance” – meaning that if you froze everything at this moment… how far away is the galaxy, and usually this is the number that’s used. But proper distance doesn’t take into account the expansion. Meaning in 200 years i.e. that distance will be greater because of expansion.

    Then there is comoving distance and also luminosity distance (used to measure the distance to supernovae). There are also other distance measures i.e. angular diameter distance. So the answer to your question lies in what distance measurement is used.

  51. #51 Richard Jowsey
    August 1, 2012

    OKThen: any conjecture about what some hypothetical “observer inside the event horizon” of a BH might experience is completely speculative. There are no experimental observations. In fact, there’s no possibility that information from “an observer” behind the event horizon could even escape the BH, so most likely we’ll never know. Given the incredibly exotic conditions near such “singularities”, reality is probably stranger than we *can* imagine! ;-)

  52. #52 Wow
    August 2, 2012

    Richard, you’re still thinking of the black hole as sucking stuff in.

    Someone inside the schwartschild radius can communicate to someone outside it. They can’t communicate out to infinity. But technically, nothing can either.

    Someone further inside can communicate with someone closer to the black hole bot not as far away as the one just inside the horizon could.

    And moreover, there’s nothing at all to suggest the laws of physics change just becuse you got a bit close to a black hole. The only breakdown you necessarily get will be at the singularity.

    Just like in the big bang.

  53. #53 Wow
    August 2, 2012

    In short, the singularity inside the black hole doesn’t start at its event horizon.

    And you forget that from the POV of the dude falling in, the situation looks completely unlike the view from outside, in an inertial frame. Turn your view into his. Not the other way round.

  54. #54 Shane Stanton
    August 2, 2012

    Thankyou SInisa! Your reply is much appreciated. I’ll do a bit of research on those ‘distance’ terms you mention.

  55. #55 Hannes
    August 13, 2012

    @Anyone

    ‘….So overall, dark energy contributes negatively (because +1 -3 = -2), and that’s why it causes an overall acceleration, doing negative work on the Universe.’

    Negative work? can’t be, since W = F.d is similar to a positive expansion.

    Only if energy is conserved in this universe (not a bad idea) negative work is a viable option.

  56. #56 Hannes
    Enschede
    August 14, 2012

    A little more explanation about this might be useful here about what I wrote above.

    The displacement of the stars, looking at them, is outward in an expanding universe. The work done by the gravitational force is negative.
    The work done by Dark Energy is in the same direction as the displacement, so must be considered positive.

    Negative work decreases the energy of a system. Dark Energy increases the energy of this universe.

  57. #57 James Fenton III
    Keno, oregon
    November 28, 2012

    I am a Pure Layman, and Don’t do math. However I noticed that in one spot, You say that the Photon, has no mass. And in another You say that gravity works to attract items that have mass.
    How can these statements be true? The light,Photons can undergo “Gravitational Lensing ” as in the Hubble Deep Field.
    If a Photon has mass, could it redshift, and at some point, have a Phase change, making it energy without mass.?
    Could this be the source of the “Problem”, in the Math?
    Also You did great, explaining the Pressure/Negative Pressure, question. Even I understood it.

  58. #58 loknat
    chennai
    December 2, 2012

    universe is so small that an intelligent scientist can reach it very fast, that is faster than light or dark energy, almost 99 percentage of the universe filled with energy which human can reach/define in later stage of development. one day the total theory of universe will change and new knowledge of universe appear in the field of knowledge and it is never ending, hope some alien will bring the solution.

  59. #59 Francis Vessigault
    Elk Grove, CA
    December 29, 2012

    I read the article about the fate of the Universe. All ordinary matter like, dust, clouds, comets, asteroids, planets, stars, galaxies, clusters of galaxies and radiation from radio waves to gamma rays all constitute 4% of the Universe. The big unseen invisible pro-gravity force, called dark matter that binds clusters of galaxies together constitute 23% of the Universe. Altogether, they constitute 27% of the Cosmos. The visible matter and dark matter are pro gravity forces. But, these are not enough to contract the universe into a Big Crunch. I know for sure, beyond any shaddow of a doubt that the Universe will expand for ever for Trillions of Zillions and Quadrillions of Galactic era, now and for ever because of Dark Energy, the dominant Force in the Infinite Universe. As Dark Energy is a repulsive force, driving the galaxies apart, almost all of them, because 73% of the Universe is the vaccum filled universe of dark energy, the expansion of the Universe for ever is an absolute certainty. The discovery in 1998 of the ever increasing red shift of distant stars and galaxies means that Eternal expansion will happen for ever. I reject out of hand the Big Crunch scenario as there isn’t enough matter to halt the expansion of the Lord’s Universe. If the dark matter amount was 60%, then it would be enough to crush the universe into a Big Crunch, but the latest research has shown that we are heading for a Big Freeze or Chill of the Universe. In 100 Trillion years from now, the least massive stars, red dwarfs will have burned out. Red dwarfs are 10 thousands of times dimmer than our White yellow Sun and have a surface temperature of a mere 5,500 F instead of 10,895 F for our white yellow Sun. Of course, shiny brilliant supergiant blue stars shine with a temperature of 22,000 F up to 44, 000 F at most.

  60. #60 James Fenton III
    Keno, Oregon
    June 3, 2013

    We have new info to share regarding the Dark Energy Source. Recent observations of Blazars, revealed the mechanism for Dark Energy, ie Photons from the Blazers are being absorbed, in the Gama energy range. It indicates that the two photons can form temporarily, a Matter-Anti-matter pair that repel each other, creating the negative pressure that we have been theorizing about. Check out Discovery’s comments on this very subject. I think it is the smoking gun that accounts for the Dark Energy “Problem” it is the”First Glimpse of Moving Starlight” article. I think it is the missing part of the puzzle regards this subject.

  61. #61 Mike Jackson
    Torrance, CA
    January 13, 2014

    My personal, layman’s notion of what DE is: It’s “anti-gravity” or negative gravity, where the further apart matter is, the more it is repelled from other matter – in inverse of what we know as gravity. This would dictate a “critical distance” at which the effects of gravity would flip from attraction to repulsion. I came upon this idea by comparing gravity to magnetism, which are analogous in various ways.

  62. #62 Garret Krampe
    Baulkham Hills Sydney Australia
    April 14, 2014

    From my reading. I’ve come across literature that gives the mass of the proton some X*10^55 mass and at the dia or 27 Fempto meters 2 protons orbit each other at one dia speration.
    Anyway Schwartzschild proton model consisted of two balck holes and all the math I saw was basic and very agreeable.
    This theory gave me great relief as it explained the universe.

    Basically the whole of the universe is made up of the same soup . Here there and everywhere. All connected at once. to the same point.

    It explained the “remote viewing” “ancestral memories” and other phenomenon which would have been paranormal psychic rubbish.. now seemingly it is that we are all sharing the same “matter” and the appearance of matter is just the interference pattern of energy events causing disturbances in the “matter / energy soup”..
    I postulate that the whole universe as we observe it is just a filtered impression or narrowband translated interpretation caused by our brains, of the bigger picture.

    Seems to me that the universe is comprised of a fractal based on planks constant (in this realm) and crosses over to another realm under that size, which is unobservable, totally.Nothing more than a spiral with nodal interference lines at “quanta” points like corpuscles creating matter , waves etc. or the illusion there-of. The “Goldern Spiral” that we see re-produced in nature and the universe every place, is actually the simplest of equations from which all “things” come. Its based on the universal gravitation equation.

    Mass / Energy would pop in and out of space seemingly randomly. Yet governed by the simplest rule, repeating for a few billion years, gains complexity, just like a fractal.

    I’m starting to see Tesla’s vision now with some clarity and Casmiri effect, Hutchinson Effect. All seem to make more sense now.

    I’m personally back to once formula and one ingerdient from which all else is made.

    CERN etc can keep smashing stuff but they can never get to the size of Plank’s Constant. I think we have all considered that Planks Constant is the “Zero” of the infinitesimally small.

    If I have a stab at the zero point exploit it would be:

    Filter, Polarize, Synchronize, Resonate,Rotate, and Tap.
    FSSRRT.

    Which is probably the sound it would make also ! lol

    I think that Tesla saw this clearly. Why else would he build rotational machines with resonant coils.
    You see at 7.83 Hz (First order of Shumann Resonance) equates to 469 RPM so the “peak of a wave would always strike the outer disk at the same spot giving the potential across the disk of the entire wave. Basically a groovy antenna in resonance due to rotation but only works at these VLF frequencies. Why wrap 9,544,239.27 M of wire to get a 1/4 Wave length ? Not a bad idea ! All he had to do was run the disk at 4*1/7.83 Hz or 1879.2 RPM ! Instant 1/4 wave antenna !
    The speed of light at that rotation speed would scribe a virtual straight line to the centre of the disk so that he could just have a disk with radial conductors and a full 1/4 wave impressed from the centre to the edge of the disk.

    I’m sorry I can’t patent that Idea. It’s a doozy in the VLF range.
    By making his coils resonate at this 7.83 Hz he could amplify the Shumann resonance greatly to what he called “useful power”. As you know he used this method to transmit energy in the wave guide that is the earth / ionosphere. He would flood the cavity with radiant energy and receive it anywhere in the world. Trouble is the polarization changes on skip so the antenna had to be a round toroidal shape.

    Are you getting the picture ?

    He was kind-of tapping the zero point energy of the solar system but more acrately tapping the solar energy in the shumann cavity, which he gave a little push from the ground to keep it resonating with a higher amplitude.

    Brain waves and most biological systems work in this same frequency or very close. SO I’m glad that he did not go ahead with it, or we’d all be nuttier than we already are !

    I’m sure that the very little energy that is naturally present in the resonance might provide a feeble source of power but pushing it along as he proposed was just messing up nature to the Nth degree. I think he realized that towards the end.

    How do you “statistically deplete” a region ? only by resonance. Resonance and a little push to break the “bonds”.

    I think Sono-luminescence showed us that.

    Sure I’m just a dabbler. It’s ok to give me a serve. I’m used to it.

  63. #63 Mike Hopper
    Indiana
    April 24, 2014

    An interesting summary of spatial cosmology, dark Matter, and Dark Energy. Highly skilled scientists look at the hard data, and propose interesting naturalistic theories for the data – (singularities, bubble universes, etc). Those same scientists then brush aside causality with little analysis or apparent concern.
    The profound fact is that by all known laws of Physics, the universe cannot have been self-creating. Nothing still comes from nothing, and Quantum Physics offers no satisfactory off ramp for answering the fundamental law of causality.
    My final comment may go unnoticed, or cause a flood of negative comments, but here goes…
    The hypothesis of causality by infinite, and living mind is just as reasonable as other naturalistic hypotheses given the known laws of physics, and observable data. The universe is simply too complex, with too many uncaused effects to exist without an architect.
    Get Ready to Hiss and Boo…I quote from a religious book that many reject, yet millions find compelling.

    Romans 1:19-20 (NIV Bible)
    “what may be known about God is plain.., because God has made it plain…. 20 For since the creation of the world God’s invisible qualities – his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that people are without excuse.”

    I find the God Hypothesis as plausible as what I find in most science discussions.