why we’re stuck with dark energy

August 21, 2009

The universe seems like a very dark place. Ordinary matter that makes up stars, planets and the vast amounts of interstellar gases is less then 5% of everything in the visible universe. Some strange, unknown substance we call dark matter takes up almost five times as much of the universe’s composition. And a staggering 73% of everything we know is actually an expression of dark energy, a phenomenon we know even less about than dark matter. While we’ve been able to produce a map of dark matter clusters based the effects of their gravity on nearby stars and galaxies, dark energy still remains an elusive beast the existence of which is being cast into doubt by two mathematicians.

dark matter map

Now, you might be wondering how dark energy can be unknown and yet account for almost three fourths of everything. The answer lies in the very complicated math behind the basic models of cosmology. Until astronomer Edwin Hubble found that the universe was actually in motion and expanding rather than the static place scientists thought it was, there was no need to consider anything as exotic as an invisible force that pushes galaxies apart. But it was possible in Einstein’s general relativity equations which could account for an expanding or contracting universe. To make sure that all of the cosmological models in these equations stayed static, Einstein added a Λ (lambda) variable in his formulas which gave energy to theoretical empty space, the so-called cosmological constant.

There was a little snag though. If the constant was positive or negative, the universe it represented would either have to undergo a runaway collapse or a runaway expansion, respectively. Since neither seemed to be happening but the universe wasn’t static, Einstein called the cosmological constant a massive blunder and abandoned it. Until the 1990s, it was just a theoretical toy for cosmologists. Then, when a survey tried to measure how fast the universe was expanding, it concluded that not only are galaxies flying apart, they’re flying apart at an accelerated rate. Using uniform type Ia supernovae as yardsticks to find the distance between us and target galaxies, astronomers saw that the objects were too dim and too far away to match up with the results predicted by formulas in which universal expansion was steady. To be that far away, the galaxies had to be moving faster and faster.

So far, the only known way to speed up a physical event like the expansion of space is to add energy to it. And here we end up back at Einstein’s formulas where a positive Λ variable provided the exact kind of energy from empty space that could explain why everything in the universe was speeding up as it flew apart. The cosmological constant was reborn as dark energy. Beyond the supernovae surveys and the mathematical basis for its existence, we know little else about it. This is where the suggestion by Blake Temple and Joel Smoller comes into play. They argue that dark energy might not really exist and what we’re seeing is a distortion of space and time streaming out across the universe as an aftershock of the Big Bang. It would be a nice and tidy solution to the dilemma, but it’s actually a very problematic way to explain what astronomers are finding.

First, to make it appear as if the universe is expanding uniformly from our vantage point, our galaxy would have to be somewhere in the center of the cosmos, as stated by Temple and Smoller. But according to an analysis of the Cosmic Microwave Background Radiation and galaxy surveys, there’s no evidence that our place in the universe is special. And there’s even less evidence to the idea that we’re in the center of it all, despite the claims of some ardent creationists clinging to Biblical literalism. Since right now, our solar system is the only vantage point we have for observing the universe, it might seem to us as if we’re in the very center of the cosmos, with galaxies as far as our telescopes can resolve in every direction. But we’d probably see the same effect if we traveled to a galaxy a billion light years away and start setting up observatories.

shape of the universeThe second problem has to do with the universe’s overall shape, which is determined by the density parameter, or the Ω. The parameter itself is the ratio of all mass and energy in the cosmos to the critical density, or the exact concentration of matter required to eventually stop any and all cosmic expansion and that in turn, helps us make a reasonable guess as to how the universe will end. If the Ω value equals 1, it means that the universe is flat, Euclidian geometry holds true at the grandest possible scale, and galaxies will just expand into infinity. For the exact details of what happens then, I highly recommend the final chapter of Phil Plait’s Death From the Skies, which does an excellent job of describing the end of a flat universe.

According to current findings, Ω really does equal 1 and the cosmos we inhabit is essentially flat. That means there has to be a certain amount of mass and energy to literally flatten out the fabric of space and time. By analyzing the many patterns in the CMBR, we can estimate the existing mix of matter and energy. But wouldn’t you know it, even when we account for dark matter, there’s still about 73% of stuff missing to account for the observations. This is how we know that dark energy must make up the majority of the universe. Without it, the universe should be open. So if the dark energy is just an aftershock of the Big Bang, how do we account for all that empty space? What else is flattening out the universe?

Finally, this is not the first attempt to explain away dark energy as an illusion. An earlier paper by a trio of astrophysicists proposed that instead of being at the center of the universe and watching an epic distortion of time and space, Earth is actually in a cosmic bubble with an abnormally low density of matter. From this unusual vantage point, we could be misinterpreting the observed galactic redshift. However, as pointed out above, this hypothesis doesn’t account for our other cosmological observations and there’s no solid proof that our location in the universe is somehow unique. We’ll still have the need to include dark energy in our calculations to make sense of what we’re seeing. Like it or not, it seems that we’ll be stuck with dark energy for a while yet…

See: Temple, B., & Smoller, J. (2009). Expanding wave solutions of the Einstein equations that induce an anomalous acceleration into the Standard Model of Cosmology Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0901627106

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  • http://www.clistersbackchannel.wordpress.com Brian In NYC

    Dark energy (mass) = we aint got a friggin clue.

  • uncertain

    I have some serious problems with the whole Dark Matter/Dark Energy theories.

    In a layman’s nutshell: this theory supposes, as does most of modern cosmology, that gravity – by far the weakest of all the fundamental forces – is the root cause of any and all celestial phenomenon. Taken a step further, since there isn’t anywhere enough matter in the Universe to account for all the “gravitational” happenings we see, there must be some kind of unseen, trans-dimensional substance that is everywhere, permeates everything, and has enormous gravitational influence on everything in the Universe. Talk about hammering a square peg into a round hole!

    An obvious and far more plausible – yet for some reason, far less accepted – solution lies in the Electric Universe theory. The main idea behind this theory, of course, being that electricity – not gravity – is the driving force behind the clockwork of nature.

    There’s many resources online, but http://www.thunderbolts.info/ has some of the best articles, research papers, multimedia, and presentation out there on the subject. Anybody with a serious interest in science and cosmology should at least give some of their material a read. It’s well worth the time spent.

  • astroengine

    Lol.

    An obvious and far more plausible – yet for some reason, far less accepted – solution lies in the Electric Universe theory.”

    So, what is so “obvious” about the EU theory? The fact it’s been made up by an electrical engineer with an axe to grind against the oppressive mainstream science community?

    EU theory is nothing less than a cult — and just because they spend a lot of time quoting 1950’s science publications, they have yet to have one single peer-reviewed paper in an astrophysics journal. Not one. Why? It’s complete bunkum.

    Dark energy, at present, is poorly understood, but reputable astrophysicists and research institutions are working on it. Why would a motley crew of non-specialists who believe in “thunderbolts from the gods” have the answer?

  • torbjrnlarssonom

    I like the general exposition here, except for the entanglement with the hypothesis of a cc as predicting dark energy. But I also have some specific problems with it:

    Einstein added a Λ (lambda) variable in his formulas which gave energy to theoretical empty space, the so-called cosmological constant.

    Confusing.

    Not that I’m conversant with general relativity, but my impression is that Einstein added the constant on the space-time curvature side of his equations. If so, a positive constant could be interpreted to take (or balance, as it were) energy.

    It was AFAIU when it was considered for vacuum energy and later dark energy it was moved over to the energy-pressure side.

    If the constant was positive or negative, the universe it represented would either have to undergo a runaway collapse or a runaway expansion, respectively. Since neither seemed to be happening but the universe wasn’t static, Einstein called the cosmological constant a massive blunder and abandoned it.

    Also confusing. I believe a zero cc, very close to the small positive one that can predict dark energy from GR, would give an expanding universe with the observed matter content and so on. Never mind the runaway situations.

    Einstein used his cc to achieve presumed balance, but it was AFAIU not an actual stable steady-state solution. Likely he was aware of that problem as well.

    FWIW, on the comments:

    Funny how people object on testable theoretical objects, since they often turn out to exist. (Compare dark matter; rival ideas can’t compete any longer.)

    But why the misrepresentation (“we aint got a friggin clue”) when the article explains the predicted characteristics? Quite frankly such falsified claims are plain stupidity, on the order of Electric Universe cultism. [Thanks for the correct characterization, astroengine.]

  • http://worldofweirdthings.com Greg Fish

    “…that gravity – by far the weakest of all the fundamental forces…”

    This is not a physics locker room where we whip out all our forces and see who’s is strongest. The range of the strong force is the diameter of an atomic nucleus. The weak force has the range about the diameter of a proton. Both gravity and electromagnetism have infinite range, but only gravity actually bends space and time which is what determines the movements of planets, stars, galaxies and galactic clusters.

    “An obvious and far more plausible – yet for some reason, far less accepted – solution lies in the Electric Universe theory.”

    The Electric Universe is a half baked jumble which takes the thousands of experiments that confirm general relativity and throws them out the window. It ignores basic physics and when presented with an example of anomalies for which it has no explanation (like black holes or dark matter), it simply disregards their existence even though we have observational proof of them. What kind of theory just haphazardly discards astronomical observations when they don’t fit its predictions?

    You saw what happens when we take away dark energy. We’re left with a gaping hole in the cosmological model and the idea that electric charges are what moves the universe around is simply wrong. On astronomical scales objects would be too far away to interact with each other due to the law of inverse squares, and quite a few objects in the universe don’t have an electric charge in the first place. Electromagnetism simply fails to explain all the movements we see and throwing away evidence to the contrary won’t prove anything.

    Take a typical EU idea that stars don’t fuse anything in their cores and all fusion reactions happen via Z-pinch events on the surface. In order for this concept to work, the Sun would need to have a surface temperature that measured in the millions of degrees and our solar system would’ve been long vaporized by the heat. If 9,800F was enough to ignite and sustain fusion, we would’ve had fully functioning fusion reactors back in 1960.

    EU will become plausible when it doesn’t have to violate well known laws of physics in order to explain how the universe works and it will become accepted by actual scientists when it can be tested and shown as correct, not because two electrical engineers blab about it loud enough and people say that it’s “obvious.” ID proponents use the “obvious” argument quite a bit and yet you don’t see good science (or any science for that matter) coming from them.

  • http://worldofweirdthings.com Greg Fish

    “…except for the entanglement with the hypothesis of a cc as predicting dark energy.”

    Well, the cosmological constant wasn’t supposed to predict anything. It just happened to be a coincidence that Einstein’s idea of playing around with the curvature of space-time turned out to be backed with observational evidence decades after he called it his biggest blunder. And yes, you could interpret a positive cosmological constant as a concentrating energy field that’s putting the breaks on universal expansion.

    “I believe a zero cc, very close to the small positive one that can predict dark energy from GR, would give an expanding universe with the observed matter content and so on.”

    An it does, but the problem is that by feeding energy into the expansion of space-time, it accelerates how fast objects are moving away from each other. It’s like free fall in a vacuum. Gravity keeps pulling you down at 9 m/s faster every second. If you never hit terminal velocity that slows down your acceleration with fluid friction, or the ground that stops you with elecrostatic repulsion, you’ll just keep on going faster and faster.

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  • peterfred

    We do not have to be stuck with dark energy. All we have to do is to do what Alice did in “Alice in Wonderland” to get out of the rabbit hole–wake up.

    There is a near coincidence between the decline in the star formation rate or the dimming of the universe and the commencement of cosmic acceleration. The dimming began at ~z=1 and cosmic acceleration began at ~z=0.6.

    What does the dimming of the universe have to do with dark energy? If light is gravitationally attractive, as my many experiments show, then there is a simple explanation as to why the universe is accelerating. Galaxies became less gravitationally bound at z=0.6 because there When they became less bound, centripetal forces weakened causing the the galaxies fly away from each other all the more producing the observation of cosmic acceleration.

    I cannot get the scientist to look at the photographs of my experiments. Why should they? They are having the time of their life spending millions of dollars of government money looking for dark energy.

    Newton said:
    “Gravity must be caused by an agent…but whether this agent be material or immaterial I have left to the consideration of my readers.”

    So if you think there is some innate inherent property of mass that can either attract other mass or warp space keeping on have a good time looking for the dark energy.

    Or if you think that energy has some innate intrinsic ability to affect mass, see my five experiments, my graph and read my paper by going to http://vixra.org/abs/0907.0018.

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  • http://thearraymbira.com william casey wesley

    Of course no one discusses the unspoken alternative, that light loses energy over time creating a red shift THAT IS NOT A DOPPLER SHIFT. Then the universe is not required to expand or contract. It seems such ideas are somehow taboo

  • Greg Fish

    “no one discusses the unspoken alternative, that light loses energy over time creating a red shift”

    No one discusses this “alternative” because there’s no proof for it. Light is a stream of photons which travel across the cosmos at c because they have no mass. Where does the energy comes into play? Why would a photon slow down? What would slow it down if it’s not affected by friction?

    Appeals to conspiracy never help a case. In fact, they do just the opposite.

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  • http://thearraymbira.com william casey wesley

    No conspiracy is required for humans to fail to consider options. Aztecs made wheeled toys but never thought to make wheel barrows. Most people naturaly tend to follow one another like birds in flight, fashion is just as prevelent in science as it is in clothing! Few people will consider a stand that will be politically disadvantageouse because funding and prestige are political advantages. This is how organized religion works as well.
    If an invitation to imagine an alternative is immediately rejected as unworkable without the cation of prior conideration being taken than I assume the reason for rejection is purely political.
    There is no final proof for the big bang yet that does not prevent people from believing in it to the point a viable alternative can not even be seriously suggested.
    Gravitational energy may gradually remove energy from light not slowing it down but LOWERING ITS FREQUENCY, not a doppler shift at all, more like a kind of COOLING process where we see such frequency shift downward. Thus no big bang, no dark energy no dark matter, no 5th force, non of the other rather extreme absurdities

  • mark

    i am just a laymen but why do they say the universe is expanding,when to me it makes sense that the universe is in freefall it must also be inside a bubble so the gases dont disperse so the falling causes gravity which makes us fall with our planet,does the bubble flatten out or increase in freefall?do you need dark matter?etc.

  • http://thearraymbira.com William Casey Wesley

    When the term “force” is used it means “unknown agency” the term force could be changed to “magic” and it would mean exactly the same thing, gravitational magic, electromagnetic magic, strong magic and weak magic. Science is supposed to trace the connection of cause and effect, where as magic relies on faith for verification. Wherever the word “force” is used its NOT SCIENTIFIC, rather its a call for us to have faith.
    Einstein tried to fix the problem of depending on “magic invisible strings” attached to objects to explain gravity, which is not a tangible scientific explanation.
    Unfortunately his explanation is twice as removed from science since by what agency is space warped? Invisible strings are still required only now they are attached to space itself rather than directly to an object in space, an even more impossible concept
    We see social groups commonly united by adherence to beliefs not likely to be adopted by outsiders, which are vauge enough to allow multiple interpretations to florish for the political reason that this expands oportunities. Multiple interpretations are allowed, and argument tolerated as long as these stay within the accepted camps.
    Viable solutions that come from left field are hated because these quell the political oportunities afforded by sustaining the accepted “controversies”
    Nearly all progress comes from individuals acting outside the pack, in exile, along with an overwhelming and obscuring host of nut jobs who are equally disadvantaged,.
    the the seriouse pioneers become a proverbial needle in a haystack of nut jobs, the likleyhood of recognition is remote
    right or wrong originality is almost never welcome in political circles even if reality eventually forces acceptance

  • http://thearraymbira.com william casey wesley
  • Greg Fish

    “Gravitational energy may gradually remove energy from light not slowing it down but lowering its frequency,”

    How? What’s the actual mechanism for doing that? Light already travels in a variety of frequencies ranging form the ultraviolet to infrared. Is there an equation that would give us an idea of how much the overall frequency of light slows over time and allow us to run an experiment?

    “Unfortunately [Einstein’s] explanation is twice as removed from science since by what agency is space warped?”

    It’s warped by the mass of the objects. Oh and another funny thing. General relativity is built on a complex mathematical framework that allows us to make predictions about how space and time should be curved in the presence of mass. Using those formulas, we’ve been able to verify that his theories were correct with thousands of experiments.

    For example, clocks for GPS satellites have to be adjusted on a regular basis due to the effects of our planet warping time and space around it. And if you fly on a plane across a continent, time flows a few picoseconds slower for you than it would at sea level according to experiments with atomic clocks.

    “Nearly all progress comes from individuals acting outside the pack, in exile, along with an overwhelming and obscuring host of nut jobs who are equally disadvantaged.”

    Actually, no. Newton, Einstein, Penrose, Hawking, Heisenberg, Bohr, Darwin, Watson and Crick were very much in the mainstream, working away on problems bothering scientists in their fields at the time, and churning out new ideas.

    I see a lot of rhetoric about how scientists are close-minded, but what I’m not seeing is any proof for your arguments. Give me an experiment, a formula, a mechanism, any piece of evidence. So far, you’re just demonstrating that you don’t have a grasp of the relevant physics.

  • http://thearraymbira.com William Casey Wesley

    I don’t think scientists are closed minded, I think they are politically influenced just like everyone else. It takes great effort to overcome political influence, most people can’t and thats why they are not highly creative.
    Ben Franklin was beaten every day for not properly attrending to his duties because he was studying and investigating science instead
    Darwin was under pressure to become a doctor, he refused. He had to say he sought proof for creationism in order to catch a ride to the Golopogos from the captain of the ship. His “theory” is STILL rejected by the majority
    Enstien was a patent office clerk, a failure in school, not even known for physics, and very much thought crazy by the majority at first
    Most of the men you mentioned were NOT on easy street but were oposed every step of the way politically from the first moment they showed independence of thought.
    Neuton had to DUMB DOWN optics to reflect popular understanding or it would not have been accepted or read

    I can only refer you to some of my fathers books for the details of the theory. the best known is ECOPHYSICS and its by JAMES PAUL WESLEY, but his self published books are better such as LIGHT A PHOTON FLUX and CAUSAL QUANTUM THEORY

  • Greg Fish

    “Ben Franklin was beaten every day for not properly attrending [sic] to his duties because he was studying and investigating science instead.”

    Um, no. He was disciplined by his parents for not doing chores just like every child of his day and age when he was slacking off in favor of his own pursuits. If you don’t think my parents objected to me skipping out on chores while I was reading books or magazines about science, you would be mistaken.

    “Darwin was under pressure to become a doctor, he refused.”

    So what? Sure his parents wanted him to become a doctor, but how is this any worse than parents today wanting their kids to grow up doing something they don’t want to?

    “He had to say he sought proof for creationism in order to catch a ride to the Golopogos [sic]”

    Sorry but that’s a fairy tale of sorts. The Beagle sailed around the world for about five years and the Galapagos were just one stop along the way. It took the entire trip for Darwin to hone in on the idea of natural selection, not just one island chain.

    “Enstien [sic] was a patent office clerk, a failure in school…”

    Yes, that was the story in Ripley’s Believe It Or Not but that was not true in any way, shape or form. Einstein was actually a math whiz and while he did fail an exam to get into a prestigious institute in Zurich, he got exceptional scores in both math and physics on that test. He became a patent clerk because he couldn’t find a teaching position, not because his theories were ridiculed or he was thought of as crazy. As soon as he was able to publish his work and the first experiments confirmed it, he was launched into rock star fame.

    “[they] were oposed [sic] every step of the way politically from the first moment they showed independence of thought.”

    Opposed? To some extent, and that applies only to Darwin. The rest had their ideas roundly debated and critiqued because that’s what scientists do. When they were shown to be right, they were given a pat on the back and positions suitable for minds like theirs.

    “Neuton [sic] had to dumb down optics to reflect popular understanding…”

    Again, no. He lectured on the subject and actually expanded his work over the years, adding all sorts of complex addenda, many of which were shown as wrong by today’s scientists. But remember that he’s still embraced as a genius and his correct work still stands to this day and was in fact, the foundation of Einstein’s masterpiece.

    “I can only refer you to some of my fathers books […] but his self published books…”

    Aha, ok. Got it. I’m glad you’re defending your dad’s work and all, but by not knowing your history or your physics, you’re not making his case any better. That said, sorry for your loss since I understand he passed on in 2007.

  • http://thearraymbira.com William Casey Wesley

    Dark matter was required to save the big bang hypothesis, but that wasn’t enough.
    Then dark energy was carted in to save it, but that wasn’t enough
    Then a fifth force came to the rescue, and that’s still not enough.
    In order to support the big bang hypothesis
    we have to depend on 70% invisible imaginary evidence
    we have to add a big wart to the standard model
    we keep getting the ‘edge” of the universe pushed outward with each new observation,
    the laws of thermodynamics get trampled completely
    we even have claims of infinite expansion energy increase, which is even worse than a perpetual motion claim
    We get claims that “space” is expanding faster than the speed of light so we don’t have to deal with the light in it moving faster than the speed of light
    We don’t know what mass is (higgs dispute) so how can we assert it “warps space” as a tangible explanation if we don’t even know what mass or space is?
    if I build a house off kilter I can “warp space” to make my formulas come out right!
    worst of all just as the fact of evolution IS IN DISPUTE because it interferes with religious belief
    the big bang may NOT BE IN DISPUTE because it is conductive to religious belief
    The rational failures listed above are substantial and undeniable…except somehow they are denied, and unsupported rationalizations like dark reality are somehow precieved as a “victory” rather than as an indication that a true need to re think our most basic assumptions is being forced upon us.

  • http://thearraymbira.com William Casey Wesley

    By the way, I never address a persons competence even if it is in question because that is the hight of political distraction, no idea can be discussed once it becomes personal. Why even respond to an opinion if its bearer is incompetent? I wouldn’t waste time interacting with someone too uneducated to be worth interacting with
    I read Ben Franklins own words on how poorly he was treated, it was far beyond what you describe. He did NOT approve even if you do. Some of the others…its unimportant, however I don’t read believe it or not….but may be quite guilty of watching a PBS show or two, perhaps they read believe it or not.
    Unfortunately thinking that family relation makes for unfounded bias would have you discount most of the worlds authorities who very often follow in their parents footsteps.
    You may reference these books or dismiss them without reading them but in these books you will find the detail of which you requested
    Interestingly you left out the third discoverer of DNA, a story that well illustrates my point about political and ego based concerns trampling the progress of science