Supernovae May Not Be Standard Candles; Is Dark Energy All Wrong? 199
StartsWithABang writes: The accelerated expansion of the Universe — and hence, dark energy — was discovered by taking the well-understood phenomenon of type Ia supernovae and measuring them out to great distances. The results indicated that they were fainter than expected, and hence more distant, and hence the Universe's expansion must be accelerating. But new results have just come out, showing that supernovae may not be standard after all. Does this mean dark energy may not be real, or that it may just be slightly weaker than we previously thought?
Dark Energy (Score:2, Interesting)
To me it seems to be used to explain the unexplainable, much like the aether of former times.
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Then maybe you should try reading about it? It isn't a neo-aether.
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What do *you* mean by aether that you can assert that Dark Energy isn't neo-aether? I think what he meant was a sketchy theory that didn't have any really solid evidence, but was widely accepted before being disproven. And that he was asserting that it would eventually be disproven.
Your assertion that it isn't what he meant is questionable.
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Both dark energy and dark matter have been verified in _several_ ways making those two very hard to replace by other mechanisms. Not impossible but anything pointing to another mechanism would be a proper paradigm shift, something that is extremely unlikely.
TL;DR Both dark energy and dark matter have solid evidence and is very unlikely to be disproved.
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I agree that the phenomena that the term Dark Energy is used to describe are real. The theory...not so much so. Is there even an agreed upon theory?
FWIW, recently the "standard candle" of supernova brightness has been called into question, so the data may not mean what people have thought they meant.
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You definitely need a medium, but the nature of the medium is highly questionable. (You need something to keep all distances from being in the same place, and a sea of virtual particles counts as a medium.)
More precisely to the point, any manifold can be considered a medium to those things that are embedded within it, as it applies constraints to what they can do, defines their neighbors, etc. And moving is done WITHIN the manifold. Please note that this doesn't even need to have a consistent metric to b
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a lot of what popular perception and popular press calls cosmology and astrophysics is pseudoscience
string theory
dark energy
even the big bang theory, commonly accepted, was formulated by a belgian priest: it's basically genesis from the bible. someone stuck abrahamic religion in the middle of "science" and no one seems to question the shaky foundations. it's just put out there without doubt or question according to popular perception and popular press. there's a lot of ways the big bang theory can be wrong
Re:Dark Energy (Score:5, Insightful)
even the big bang theory, commonly accepted, was formulated by a belgian priest: it's basically genesis from the bible. someone stuck abrahamic religion in the middle of "science" and no one seems to question the shaky foundations.
Unlike politics where you need to reject ideas because it came from an opposing group, science doesn't care where the idea comes from if it works. The foundations of the Big Bang theory is not its history, but general relativity and the observations that back up things like the FLRW metric. History is only indirectly important in science, in that it is a great pedagogical tool for showing how an idea developed, why some ideas worked and why others failed, for teaching students the process.
Re:Dark Energy (Score:4, Informative)
We've got the hubble expansion and cosmic background. Both of which point strongly towards an expanding universe with a point-like origin. Cosmologists hotly debate a lot of the details, but their agreement on the fundamentals is near-unanimous.
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Cosmologists hotly debate a lot of the details, but their agreement on the fundamentals is near-unanimous.
Those who want to believe otherwise rarely let that get in their way, that we're still working out the minute details of complex interactions is an easy way to dismiss everything. See evolution, the climate, medicine, nutrition, ecosystems, pollution, almost everything that doesn't reduce down to a physics/chemistry experiment really.
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In fact, the fact the observable limit tells us was that universe "banged" some finite time ago. In a solid state universe we would have infinite amounts of light coming from infinite distances. And we don't. Whilst this doesn't speak to whether the universe is infinite or finite in size, it does tell us quite conclusively that light has only had a certain number of billion years to propagate, meaning that it *started* , which pretty much rules out the solid state theory.
Throw in a tonne of other evidence
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we can not ignore the assumptions that take root in popular media and imagination
Why not?
Regardless of what the populace thinks... science will continue. It's been that way since the beginning: scientists push knowledge forward and society comes along when it's convenient.
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science serves the public interest. you should care, because it effects you. science does not occur in some ivory tower isolated from other concerns in the world. if the beliefs of antivaxxers means you get infected or the beliefs of climate change deniers means your house floods, you should care what the average person thinks
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the expansion we see is simply a local phenomenon ("local" being many billions of light years across) like the crest and trough of waves on the open ocean. the CBE is a phenomenon that happened a long time ago "locally", and delineates the edge of what we can see
that's just a theory
but it's no worse of a theory than the idea that there is a big bang that encompasses the entire universe, not just what we can see
why is the edge of what we can see = to the edge of everything, period?
proof? the "proof" is a res
Re: Dark Energy (Score:3)
Because we can't ever observe or in any way interact with anything beyond our visual horizon. You can tell stories about what's "outside" all you want, but they're just stories. Until they have some impact, even just in principle, on the universe we can interact on, they're completely irrelevant.
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i am not saying the steady state theory is correct. i am saying we cannot say the big bang theory is authoritatively correct
everything about the big bang theory proves local expansion, not necessarily all expansion
i am simply saying that we have no proof that the edge of all we can see == the edge of all there is
which has been a common fallacy throughout the history of science, especially astronomy. it's egocentrism, a simple common human weakness
can you tell me conclusively that the edge of all we can see
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Science isn't very good at conclusively proving things, but its awfully good at disproving things.
For the steady state theory to be true, a few things must be true. We would have near amounts of light bombarding us, since the universe would have been around for an infinite amount of time at an infinite size thus being able to shoot infinite amounts of light in all directions for the fo
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No-one is questioning expansion;this is about rate of expansion.
Re:Dark Energy (Score:5, Insightful)
Unless you plan on challenging the First Law of Thermodynamics.
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nothing you said contradicts anything i said
you seem to be reacting to the use of my term "cheat sheet," which is a turn of phrase that you are placing extra meaning into that i did not imply. you are reacting to that extra assumed meaning
because from where i am sitting, we are in perfect agreement
so i apologize for using an inexact phrase
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The first law of thermo dynamics simply says the the total energy in a system is constant.
I can not see how that is relevant to your standpoint or the discussion.
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Re:Dark Energy (Score:4, Informative)
Dark energy can also be measured from the CMB radiation, through the angular size of anisotropies and through baryonic acoustic oscillations in the large scale structure.
And the constraints from these *independent* probes are consistent with the results from supernovae, all pointing to the presence of an acceleration of the universe at late times. It is not so that we rely on a single tool here!
Also, TFA states that their finding that a different class of supernova is dominant at high redshift does not attack the presence of dark energy, only its exact value (of energy density).
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Doesn't the entire concept of Dark Energy challenge the 1st Law? If space is expanding at a constant rate through time (and I believe the available observations suggest it is), then the energy fueling that expansion must itself be constantly increasing to fill the increasing amount of space. Otherwise we'd see an exponential decay in acceleration as a finite amount of expansion energy became increasingly diffuse.
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Well, that's one of those place where we *know* our theories are broken - General Relativity requires that the energy in empty space is exactly zero, while Quantum Mechanics requires that it be positive.
There's also the fact that, even ignoring expansion energy (which must be created along with the new space to keep the expansion rate constant), you also increase the gravitational potential energy of the universe: insert a little extra space between Earth and the Sun and you push both slightly out of each o
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Heat is visible, for one. It's only our eyes that didn't evolve to see it. Plenty of other animals, and many of our telescopes can see it just fine.
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At the risk of being a smart-ass, how is heat that's decoupled from all normal interactions with matter meaningfully classified as heat for any normal context.
Of course the original ACs comment is... questionable... to begin with. "the particles in space material containing heat"?
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Thermalization in that context is a largely unrelated phenomena, referring only to the speed distribution profile of the constituent particles, rather than any sort of latent heat in them. Yes, it's similar in principle to the manner in which heat is stored in a monatomic fluid, except that a normal fluid can transfer heat to surrounding/immersed objects through particle collisions, whereas dark matter cannot. Though I suppose there would llkely be some minor heat leakage with co-located normal-matter as
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I sort of agree with the above, up to a point.
I have a very simple view of physics, which works well enough since I'm not involved in any of its messy internals. It goes like this:
Physics is similar to Calvin Ball, in that you make up the rules as you go along. But unlike Calvin Ball, all but one of the rules is malleable; all but one rule can be changed at any time.
The one absolute, unchangeable rule is that every other rule in physics has to allow every mechanism that any engineer successfully builds t
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i like that
i response with a quote from the great mystical philosopher donald rumsfeld (i'm joking... about him being great or a philosopher, the quote is real, and a good quote, to give him credit):
http://en.wikipedia.org/wiki/T... [wikipedia.org]
the simple point is the big bang theory can
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Thank you very much for the Donald Rumsfeld quote. I was trying to remember it the other day and while I had the sense of it right, I was not as succinct as Rumsfeld and my memory kept offering Oppenheimer as the author even though I was sure that wasn't right. So naturally Google was no help.
Sometimes its better to not know something than to know it wrong...
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And newton was practically a religious fundamentalist, Algebra was invented by a muslim cleric (Al-Gebra!) and so on.
The reason we are fairly confident about the big bang is because we have [i]very strong evidence[/i] for it, namely the microwave radio background which more or less lets us *look at* the big bang, or at least its aftermath, and a whole slew of other observations, including the fact the universe seems to be red
Re:Dark Energy (Score:5, Insightful)
*I* am only asking that you use the Shift key on your keyboard every now and again!
If you want to be taken seriously you should really start with good sentence structure, proper paragraphs and punctuation. Your double spaced scrawling looks like the work of a child and you will be treated as such. All of this undermines your already eccentric views to the point where no one can take you seriously.
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so don't respond, don't read, don't ever look at a post of mine again
agreed?
good bye
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To me it seems to be used to explain the unexplainable, much like the aether of former times.
It's exactly what it is. To scientists, "dark energy" is a placeholder, a spot where they say "We don't know".
In cosmology, the placeholder is pretty important in allowing them to continue working, and not just shrugging their shoulders and stopping.
So just like aether and Phlogiston,(the best word ever invented) the placeholders are stepping stones. When we discover whatever it is, it probably won't be called dark matter, and "dark matter" the name will be placed in the cosmology dustbin along with the
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It's exactly what it is. To scientists, "dark energy" is a placeholder, a spot where they say "We don't know".
That description isn't really accurate, since dark matter and dark energy add important corrective factors to many models, and many scientists spend lots of time trying to model more things involving them... They thus are moch more formalized and manipulated than most " placeholders."
In cosmology, the placeholder is pretty important in allowing them to continue working, and not just shrugging their shoulders and stopping.
I agree to some extent....
So just like aether and Phlogiston,(the best word ever invented) the placeholders are stepping stones. When we discover whatever it is, it probably won't be called dark matter, and "dark matter" the name will be placed in the cosmology dustbin along with the other old theories
Yeah, this goes off the rails a bit. I'd hardly call things like aether and phlogiston "stepping stones" -- they may have been initially, but they became over theorized and explanatory elements in the
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I'd hardly call things like aether and phlogiston "stepping stones" -- they may have been initially, but they became over theorized and explanatory elements in their own right, and they ultimately led to a lot of wasted theorizing and going down blind alleys looking for explanations for things that weren't perhaps even real problems.
But that is what is happening with dark energy. It is being used as corrective factors to make other parts of physics work out, in much the same way that adding more epicycles was used by pre-Cupernicus astronomers to make the motions of the celestial bodies work out.
The core problem here seems to be that the "laws" of thermodynamics are wrong. There is probably some reformulation of those that would make dark energy and dark matter disappear in the same way Cupernicus made all the epicycles disappear. Tha
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There is probably some reformulation of those that would make dark energy and dark matter disappear in the same way Cupernicus made all the epicycles disappear.
Random history of science note -- what you say about Copernicus is a myth and a complete misunderstanding of his theory, which basically required just as many epicycles as geocentric models at the time.
Copernicus -- and Galileo later on -- insisted on circular orbits, which still required plenty of epicycles and didn't actually simplify the math as much as the myths claim.
It was Kepler and his elliptical orbits (which Galileo rejected) that actually got rid of the need for epicycles permanently. Once o
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Of course you are right and I stand corrected. I did not research the literature. My bad.
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Oh, I agree. Sometimes corrections work out well enough for the engineers to make fancy new things. Physics doesn't have to be right. It only has to be right enough.
As to neutrinos and antimatter and all that subatomic mess. Once it was simple: Bohr atoms and neutrons, protons, electrons, and photons. Then the physicists had to start adding corrective wavicles, like neutrinos, then quarks, then multiple different types of quarks, etc, etc. Now we've got this huge particle accelerator to find even smaller,
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It's exactly what it is. To scientists, "dark energy" is a placeholder, a spot where they say "We don't know".
That description isn't really accurate, since dark matter and dark energy add important corrective factors to many models, and many scientists spend lots of time trying to model more things involving them... They thus are moch more formalized and manipulated than most " placeholders."
I call that placeholders, something we don't quite know about that is used to make the theory fit. It isn't a problem, and it's how cosmology moves forward. Most of it fits, but there's this "little anomaly."
So just like aether and Phlogiston,(the best word ever invented) the placeholders are stepping stones. When we discover whatever it is, it probably won't be called dark matter, and "dark matter" the name will be placed in the cosmology dustbin along with the other old theories
Yeah, this goes off the rails a bit. I'd hardly call things like aether and phlogiston "stepping stones" -- they may have been initially, but they became over theorized and explanatory elements in their own right, and they ultimately led to a lot of wasted theorizing and going down blind alleys looking for explanations for things that weren't perhaps even real problems.
You just described exactly what dark matter has become. Dark matter as a word has become something that isn't actually "matter" in the way we think about matter. It's something else, but it's dark matter. Is it dark? Is is matter? Does it matter? It's now a thing.
The issue with "placeholders" is that they turn a set of unexplained observations into a THING -- they reify or hypostatize it.
Which is exactly what has happened to da
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I think you spent so much time looking for something to disagree with me about that you missed the point that we're darn close to exactly agreeing.
I find your interpretation of my post odd given that I *explicitly* noted that "I agree with you to some extent." I do agree with a lot of what you said, and I wasn't really looking to disagree.
That said, to me your term "stepping stones" implies a stepwise progression going in the right direction, as when one uses stepping stones to cross a creek or something -- that term usually indicates something that is used to progress toward a goal. My point is that these "placeholders" can also function as imped
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I'd hardly call things like aether and phlogiston "stepping stones" -- they may have been initially
That would be the 'stepping' part in the definition of "stepping stones".
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To me it seems to be used to explain the unexplainable, much like the aether of former times.
The aether was a pretty reasonable postulation given the observations of the time.
It got disproved. Dark energy might. Or might not.
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More specifically, we would be looking to disprove the *need* for a placeholder like Dark Matter or Dark Energy, and not the existence of any one possible candidate.
All we have now are a bunch of requirements for "something" which will make observations match existing theories/models. Some have taken that need one step further and suggested some candidates which could fulfill the requirements for the "something".
That said, no one has been able to strictly prove that the need for the required matter/energy
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much like the aether
...and gravity, it is a model that fits our observations. [tufts.edu]
Re:Dark Energy (Score:5, Insightful)
The neutrino was in the same state for a while -- a hypothesized, unobserved entity needed to make the equations balance. Now we have three different neutrinos plus their antiparticles.
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much like the aether of former times.
It *is* the aether of former times, minus the materials sciences metaphors.
Everyone agrees there's *something* in the 'vacuum' - why not call it aether?
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Weak evidence necessarily leads to weak conclusions which are more likely to be wrong.
In this field such weak conclusions are the *strongest* available and thus the ones most discussed.
This is common and acceptable in the fields that are harder to study such as anthro, psycho and thero physico. Everybody who is credible in those fields understands this and probably finds it more exciting than a field with "less" to discover.
Reporters on the other hand just report whatever shit they think is click bait
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Real scientists get very worried when they hear the term "scientific consensus". That kind of talk isn't scientific.
The republic of science (Score:2)
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1) Different people mean different things by consensus. E.g. some people mean unanimous agreement.
2) You have correctly described much popular commentary in the general press, but there often is an actual consensus underneath what they are saying, they just aren't accurately describing it. And sometimes it's whole-cloth invention. And sometimes its "Many people I've heard from when I asked about it and could get someone to talk to me."
3) The checks and balances are monopoly ownership of the public media
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"We" being nutcases, right?
No, the aether doesn't exist. If you're going to claim "the vacuum of empty space is the aether", then you'd be just as well calling it the FSM, and then claiming the same thing. Words are supposed to mean something. If you're gong to use a private language definition of the word, please stop talking to anyone.
Re: Aether (Score:2)
Quantum field theory proposes all-pervading fields that give rise to all observed phenomenon. The Higgs field even has nonzero energy everywhere, and light is a disturbance that propagates through the electromagnetic field. That hits all of the common points for the turn of the century aether theories.
Einstein's relativity itself is a very aether-like theory in that one of the most popular interpretations is a geometric description of curvature in all-pervading space.
You've clearly bought into the "silly ae
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Words are supposed to mean something.
That never stopped "dark energy".
Re: Aether (Score:2)
Well I hadn't previously really considered this, but in a way the current understanding of the duality of light and matter and the sea of virtual particles that fill empty space isn't too far off from the concept of an aether.
Re:Aether (Score:4, Informative)
On the internet, apparent aether refers to whatever people want when they want to sound disparaging about a particular idea they don't like. Within physics, it pretty specifically refers to a medium for electromagnetic waves, that for most of its versions in history was a fluid of some type. If people on the internet want to redefine it to mean anything permeating space so they can treat things like dark energy, they should at least be consistent then and acknowledge things like gravity and wavefunctions that also permeate space, among a whole bunch of other physics concepts. In that sense, we've known the "aether" to be real since components of Maxwell's equations started coming together with ever present electric and magnetic fields.
Re:Aether (Score:4, Interesting)
No, science has never disproved the aether. It was ruled out for social reasons. When that social reality changes, science will probably bring it back. Yves Couder's experiments with silicon "walkers" bouncing on a liquid substrate, with which he can recreate Young's double-slit experiment on a macroscopic scale, would fit nicely with aether theory. But that fit is ignored by physics, because of the social ramifications of bringing back aether theory.
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I don't know who's modding this up, or where you got the idea that Couder's experiments fit nicely with aether theory. The experiments have nothing to do with aether theory, other than showing some mechanical analogues of particular systems. They don't show a fluid basis for all of quantum mechanics, just a particular experiment. While the experiments are nice, this shouldn't be surprising considering the basis of quantum mechanics is wavefunctions, which do show a lot of similarity to waves in general (
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Thank You!
I've felt alone on this issue for so long. The removal of the "aether" happened around the time when Physicists adopted Einstein's theories (after apposing them tooth and nail for so long) and Quantum Mechanic became the trend.
I've always felt that the "particle of the week", the Higgs Boson, and Dark Matter were all attempts to compensate for two phenomena; today's physicists MUST explain everything with a particle, and they MUST not say that space is made of the aether. Though the Holographic an
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A lot of people are not getting why Quantum "phenomena" can be explained as a wave on a medium (like water) and they think it's just happenstance and wave functions just crop up everywhere (yeah, sure, like the Golden Rule!).
If there are waves -- what do they propagate through? A particle doesn't lose mass propagating EM fields -- only energy, or more exactly; inertia or heat. Sound does not transfer in space, because it is a vacuum. But that's only because sound is a wave function that passes along molecul
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No, science has never disproved the aether.
Inas much as you can't disprove anything. However, the isotropy of the speed of light essentially suck the ether as a theory, because the anisotropy of the earth moving relative to the ether was one of the big predictions, especially given Maxwell's laws. Then along came relativity and stuck the boot in.
The aether made predictions which didn't come true. The theory was modified to fir the observations, which is not ususual. However in the case of the aether it beca
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Re:Nice try (Score:5, Informative)
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I think there are two big differences:
1) Scientists are willing, even eager, to be proven wrong about this and find a better explanation.
You haven't met many of the horribly obnoxious people who wind up in cosmology have you ?
Really surprised this managed to find a friendly review committee.
Re:Dark Energy (Score:4, Insightful)
Do you know Deepak Chopra? I have a feeling you two would get along nicely.
Wrong on many counts (Score:2)
Perhaps you need a refresher on what a model [wikipedia.org] is.
and
As to there being no math [just-think-it.com], all this does is prove you haven't [just-think-it.com] reviewed my theory. So how on Earth can you comment on something (let alone get an up mod) when you obvi
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Re:Dark Energy (Score:5, Insightful)
That link starts off interesting, and by about the 5th or 6th page becomes just polemic. You need to rewrite every page after the 1st, giving more attention to your theory and less attention to lambasting others.
I *am* of the opinion that when you do this you will end up with many fewer pages, but quite possibly with some decent questions that need to be addressed. E.g., how does your theory account for the proportions of Hydorgen and Helium in the universe. Etc. Don't concentrate quite so much on problems that current theories have trouble with, and pay more attention to deriving the solutions that the current theories have apparently valid answers for. Yes, you need to point out places where your theory is better, but it's even more important to show that you can answer correctly everything that the current theories have correct.
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Someone on this topic need to mention, "Timecube." There, I've fulfilled my duty.
Re:Dark Energy (Score:4, Insightful)
If you are referring to Einstein, someone who grew up reading books by leading scientists, had a formal education in physics, and continued to keep up to date with theories and experiments and had connections to many people in the field, that is no longer just a "simple" patent clerk in this context. And that still doesn't explain why some such people show up in response to every related story.
Some of the posters here on Slashdot just keep copy-pasting statements with very little change or response to discussion. They also tend to reply only to easy to dismiss criticisms, like those that made an obvious reading comprehension fail or posts that are just insults/trolling or otherwise content free. But at the same time ignoring any detailed or serious replies (or ignoring 90% of such replies, going off on tangents), and never incorporate any suggestions or advice into their ideas.
They're not looking for discussion, they're just looking for validation or up mods from uninformed. If you post the same wrong stuff enough times on Slashdot, it inevitably gets modded up from time to time faster than it can get noticed by someone who can make a coherent counterpoint. Then sometimes momentum just means the comment stays modded up despite unmodded or down modded replies, regardless of how trivial it is to see the replies are right by looking at something as simple as a textbook.
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DIfferent thinking to gravity (Score:1, Interesting)
Imagine a planet with one nerd on it. Every second, the planet and the nerd individually double in size. Because of this, the nerd feels a downward pull because he's expanding downward toward the planet and the planet's expanding upward toward the nerd. This theory is yet unconfirmed; AFAIK it cannot be proved because we possibly live in that world.
"Dark Energy" could just be a different way of thinking about gravity, much like the previous paragraph could be how our real universe works.
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I would think this case would be easy to distinguish from others. Basically if matter itself were expanding the way we often talk about space as, yes I could see this constant expansion pressure looking a lot like gravity but, anything on the surface that was expanding would also be moving further away from anything next to it, so if you built a structure, the walls of the structure would suffer increasing internal stress from the expansion AND its corners would be pulled away from eachother by the ground e
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If I had to choose between Dark Energy and expanding space or not expanding space and object moving through space fast
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We haven't measured things moving away from us faster than light
We have measured red shifts that indicate a rate of over 2c moving away from us. An object moving faster than light can still be seen if it was in our light cone at the time it emitted the light.
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We have measured red shifts that indicate a rate of over 2c moving away from us.
No, we have not. There is no defined redshift for speeds faster than c. The largest redshift we have is for the z~1100 for the CMB, which corresponds to a velocity of 0.999998c.
You may want to do a bit of reading http://en.wikipedia.org/wiki/R... [wikipedia.org] Quote: Due to the expansion increasing as distances increase, the distance between two remote galaxies can increase at more than 3×10^8 m/s
This is old news. I assume you're trolling or willfully ignorant.
Funding (Score:2)
If Dark Energy turns out to be a placeholder for a revision to the model for gravity, it could be explained by some smart physicist sitting in his office tweaking the model to fit observations.
If Dark Energy is an acutal force, there may very well be a particle associated with it. And we can discover this particle given a large enough collider (and by implication the funds to build and operate it). If I were an physicist, I know which argument I'd support in order to ensure job security.
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That the sun that planet orbits doesn't get closer and closer would be a pretty good indication that the "everthing is doubling in size" explanation for "gravity".
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If you're inside the object, only the radius below you counts. Theoretically. I mean who spends significant amounts of time underground?
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who spends significant amounts of time underground?
Slashdotters.
These jokes just write themselves.
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Dark energy appears to be doing just fine (Score:5, Informative)
According to Ethan Siegel [medium.com], dark energy isn't written off, we just know a bit more about it.
Link to the full article, freely available (Score:5, Informative)
The summary has a link to a paywalled article (silly Ethan). The full article is freely available to all on the arXiv preprint server:
http://arxiv.org/abs/1408.1706 [arxiv.org]
I'm peripherally involved with the supernova field, though I study only the nearby examples. There has been for years the understanding that IF a difference should arise between the nearby events that we can study well, and the distant events which appear dimly and vaguely, AND if we did not realize that such a difference existed, THEN we could reach incorrect conclusions.
Scientists in the field have worried about this for years. It's not a sudden new realization.
It's very pleasant to see that a space telescope -- SWIFT -- which was built to study one type of object (gamma ray bursts) has turned out to provide vital information on a different type (supernovae). Since it is in space, it can detect ultraviolet light, and so show us that some nearby supernovae emit different amounts of ultraviolet light, even though they appear similar in the optical region. This UV difference hints at differences in chemical composition between supernovae, which may indeed be significant when we try to study very distant events with other telescopes.
Fortunately, light from those distant events is redshifted into the optical regime, so we can use very large ground-based telescopes to see the same UV light and compare it to the nearby events.
It's a very interesting field to follow: things change on timescales of 3-5 years. And yes, we are more aware of the uncertainties in the business than some news articles might imply.
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> There has been for years the understanding that IF a difference should arise between the nearby events that we can study well, and the distant events which appear dimly and vaguely, AND if we did not realize that such a difference existed, THEN we could reach incorrect conclusions.
Thank you for being so clear. I hope that your colleagues appreciate the rigor of your thinking.
I've actually become suspicious, as an educated layman, about the other underlying assumptions that may confuse our cosmological
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In addition, big bang nucleosynthesis models place strong limits on how much baryonic (protons, neutrons) matter there can be and it is not enough to be the dark matter.
More to Dark Energy Measurements (Score:5, Informative)
*If* this result holds up, it doesn't sink dark energy - it will only be a small correction to the measured value using this particular probe. We have multiple, independent measurements of the existence of dark energy, from the early-universe Cosmic Microwave Background, to the late-universe feature in the galaxy distribution called the Baryon Acoustic Oscillation. In fact, for quite a few years supernova haven't been the principle method of measuring dark energy, because we've suspected issues such as this.
*If* this result hold up, and corrected measurements of dark energy from supernovae are in tension is all other measurements, then that will be interesting and require further study. However, despite having the confirmation of the existence of dark energy for several years, we haven't measured its exact properties very well yet. These corrections will probably shift things around inside known error bars.
For all the aether-claimers: we don't know what dark energy is. We've observed an acceleration to the expansion of the universe and called it "dark energy". This is a name given to an observed phenomena. The Nobel Prize was awarded to the original supernovae groups because it has been *repeatedly, independently* verified, using completely different sets of cosmological probes. This is like observing and measuring the observational reality of gravity without having a theory to explain it, but that doesn't mean that gravity doesn't exist.
The Force (Score:2)
Re:The Force (Score:5, Funny)
Slashdot clickbait headlines (Score:2)
Headline: Supernovae May Not Be Standard Candles; Is Dark Energy All Wrong?
Summary: Does this mean dark energy may not be real, or that it may just be slightly weaker than we previously thought?
Articles: It is slightly weaker than we previously thought. Not significantly though.
"dark" energy is stupid (Score:2)
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I vote for steady state
It doesn't matter what you vote for or what you believe. The data says you're wrong.
To head off this inevitable statement: "But this debate proves that we don't really know anything!"
No, no it doesn't. Read this before you go any further:
http://chem.tufts.edu/answersi... [tufts.edu]
--
BMO
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Dark energy is *not* confirmed, but the need for something like it to explain the observations has not been removed by the change in the standard candle. So, contrary to the headline: it is still status quo.
More specifically, instead of a Type Ia supernova always having the exact same characteristics throughout the universe, they discovered that there are two types of Type Ia supernovae. They are still standard, but now there are two standard sub-types.
Since we assumed that all of them were exactly the sa