Supernovae May Not Be Standard Candles; Is Dark Energy All Wrong?
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?
To me it seems to be used to explain the unexplainable, much like the aether of former times.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
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.
"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.
According to Ethan Siegel, dark energy isn't written off, we just know a bit more about it.
"Money is a sign of poverty." - Iain Banks
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.
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
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.
Michael Richmond "This is the heart that broke my finger."
mwrsps@rit.edu http://stupendous.rit.edu
*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.
Huh. Does that mean I can use the word "aether" to refer to government surveillance?
Maybe the Dark Side isn't winning.
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...
--
BMO
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.
Have gnu, will travel.
Perhaps you need a refresher on what a model is.
and
As to there being no math, all this does is prove you haven't reviewed my theory. So how on Earth can you comment on something (let alone get an up mod) when you obviously haven't read it?
Your statement that there is "no physics" in my theory is so far from reality that I must conclude that I am trying to reason with a troll. Which I will stop doing, immediately.
I come here for the love
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 aether" folk mythology. There were many theories of aether, some of which were quite compatible with the Michelson-Morley results.
The aether theories made some specific predictions, and even after several revisions to that, every single one was found to disagree with observation. Even if you attempt to rebrand some different new concept as an aether theory, that is just a semantics trick and doesn't change that original set of theories were found wrong.
Words are supposed to mean something.
That never stopped "dark energy".
Then you can't prove I'm wrong about the aether not existing, therefore have to accept my claim.
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.
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.
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 (wave equations are a common solution in a lot of areas of physics, because it is such a simple and common differential equation). Heck, the Schrodinger equation and variations of it are used heavily in modeling water waves in certain regimes.
But this has nothing to do with the idea that mechanically there is a fluid providing the mechanism behind electromagnetism or quantum mechanics. At best you get to an interpretation of some aspects of quantum mechanics, but it doesn't make any observable difference and remains an interpretation.
This is rather unlike aether theories of yore which made predictions, predictions that turned out to fail. If after multiple revisions & variations, with multiple follow up experiments to each revision of theory resulting in disagreement and lower bounds, is a "social reason," then so be it. But that doesn't sound like what you are saying. Considering the famous Michelson–Morley experiment wasn't the start or the end of it, with many experiments both in the decades before and decades after, that wasn't just a group of theories failing for social reasons.
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 matter aka matter that doesn't interact with other matter or most radiation and simply causes gravity is unlikely but plausible. Dark energy, energy that doesn't interact with matter but does interact with matter to accelerate it outward doesn't even make sense at a basic level. I thought expansion was based on the dopplar effect on wavelengths of light from all stars. Since when was it based on supernovae?
If it can't be falsified nor verified, then it does not exist.
I have always imagined dark matter to not be able to radiate itself being to fine grained, in space there is no temperature, no complex atoms structures because no atmospheric pressure to form these oxygen atom configurations. the ingredients for light are just not in space as they are on earth, if a burn can not happen in space, light can not come in to existence, only like the sun does it chemically. i think dark matter consists of many particles together but all are so fine and in there indivisible form not able to radiate light because a super tiny particle can only hold a little heat, not enough to radiate hot enough for generating visible light, therefore I think dark energy is just heat, or temperature seen from a distance. so space material containing heat or not. if not, the material is in a complete rest state. (space) I theorize a maximum distance light can travel, once it has lost its velocity and heat of the particle it comes to rest and becomes space material itself. the particle wave only happens on earth, not in space as direct sun or starlight cant be seen in space. the wave or the burn part of the effect only happens on earth. we can only measure lights speed or the particle velocity WE give a certain particle. our particle stream we generate always originates on earth, even if we send a laser light signal to the moon and back it has already been limited to the speed of light (on earth under atmospheric pressure). if we were to measure the velocity of light in space where both points are completely in space and the length was long enough could we see a difference. except were not there yet, we never know exactly the time a particle leaves its origin point in space we only have a measuring point once it arrives, never do we know how long it has travelled.
Of course we're not on a balloon, everyone knows we are the raisins in an expanding pudding.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Don't talk nonsense and dress it up as "scientific". "Scientific consensus" is just the modern phrase for what Karl Popper called "the republic of science". People who complain about the meaning of either term are not scientists, they are usually partisan political hacks who have never heard of Karl Popper and think AGW is a some kind of gigantic conspiracy to take away their SUV.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
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 and "Pixel" Universe theories come close.
And then there's that whole "light is a particle and a wave conundrum" that seems like just a fight against common sense. Microwaves make up a larger spectrum than visible light in the EM band, and then you've got radio waves. ALL of them are waves. Only when we get to this distinct frequency where the wave moves in a narrow direction, is there a question of particles. If the other EM energies are all waves, why suddenly would visible light be a particle?
Quantum phenomena occurs because waves only distribute energy on interfering peaks, and "empty space" is a thing, and it's just not part of our 4 dimensions -- and THAT is what gravity pushes against. So there; that's going to take about another 20 years for someone to work up the math and accept, or we'll have a Higgs Boson -anti-dark matter particle to explain it.
>>"ad space available -- low rates!!!"
I think you are right in that dark energy or heat is contained in side dark matter, since the particles in dark matter are very small it can not contain much heat or energy..... therefore is hard to find.
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 same, that may have messed up calculations that were expected to be more accurate than they actually are. Now instead of saying that object is 1.6 Mpc away by this method, it is now either 1.6 Mpc away or 1.2 Mpc away because there are now two possible types of Type Ia supernovae. However, because both sub-types are actually standard, one of the two of those is correct and you could, in theory, account for that.
Anyway, using the CMB and BAO a s a "standard ruler", they independently verified the current figures for the expansion of the universe, so this new discovery has not kicked the legs out from under the investigation. Indeed, it is possible that even if supernovae were the *only* way of making this measurement, the recalculation would still have required dark energy, just not as much as was expected.
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 molecules.
Shouldn't it be proved that there IS NO MEDIUM for waves like light to propagate through? Seems to me that the Photon as more than a "point at which a specifically tuned field collapses" is a more reasonable answer than making one band of EM field have a particle and not finding particles in microwaves (for instance). And as an exercise -- can someone explain WHY they oscillate back and forth as waves on an ocean do if there is not a medium? I can only come up with a way to explain oscillations in a vacuum by looking at a straight line in 8 dimensions -- which still doesn't rule out a medium in a co-incident dimensional group (another 4 dimensions).
Anyway, I'm frustrated because I can conceptualize most of what is said in Quantum Mechanics, and other than the math -- it sounds like they are describing a Platypus and not a beast that could actually live. There are indeed simple explanations that can satisfy the double slit experiment with waves alone, and also Quantum Mechanics -- as long as EVERYTHING is really a wave. And particles are waves -- they just fold in on themselves in our 4 dimensional space.
The thing I've pondered for the longest time is "why physics is a law"? -- meaning; why do things HAVE to be equal and opposite? We've observed that, and Newton and a few others have proved that it happens -- but I want to know why. And "how do things move" based on Einstein's theory of Relativity because, when I was 12, sure, I spent three days wrapping my head around the basic concept -- but it didn't make sense with a lot of different vectors. It took me years to realize it was another concept that people nodded their heads and echoed "E=MC2" without really understanding. You've got people who can't get beyond the accomplishment of understanding that two photons don't hit at twice light speed, and after that, they take a nap.
The idea that Space/Time stretches for two photons colliding but shrinks if they separate starts to break down if you think of a star where it's often the case that a photon is both arriving and leaving another at relativistic speeds. It means that EITHER; each particle has it's own relativistic space/time or motion takes place in a higher and lower dimensional group. And what does it mean to shrink and stretch space in such a small area?
However, if we say that SPACE is a thing and is moving; then relativity is the "pressure on space/time" -- and it works out a lot nicer conceptually to think of velocity and gravity as pressure. So as the Gravity goes up in a star, it takes more energy/speed to reach light speed -- and it works out a lot like turbulence. As a bonus, we can say that gravity on a planet or a star may have less effect on local objects than on the galaxy itself -- and thus, noting that a lot of galaxies are MUCH HEAVIER than predicted, we can be OK with the fact that gravity may be a lot more powerful than predicted -- but it's pushing on SPACE itself. Where there is a lot of matter and light -- there's more pressure and turbulence, so the objects are not being forced towards other objects. I mean, why don't electrons merge with protons and why didn't the Universe get all clumpy after the Big Bang? Math models predict what we see because they are tweaked that way. But If I've got a room full of magnets and toss them around, they clump up because ALL they do is attract each other. If Gravity is JUST an attractive force -- it's pretty lazy about it.
A balloon with helium "shoots up" in our heavier atmosphere because of equalizing pr
>>"ad space available -- low rates!!!"
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 became more and complex and eventually, all of the phenomena were explained without the aether. That left the luminiferous aether as a really cool name but lacking any predictive or explanatory power, so it was dropped.
I think it's very unlikely the aether will return, because physics has moved on very far since the aether was the best explantion for the physics.
SJW n. One who posts facts.
Microwaves make up a larger spectrum than visible light in the EM band, and then you've got radio waves. ALL of them are wave
Microwave photons are quite regularly used in experiments on chip and tabletop based cavities, including a lot of quantum computer researching setups.
There is no sudden cuttoff, it is all just a matter of scale. Just like when determining when you can describe something as a wave or not in classical electromagnetism, if the frequency is high enough or distances large enough, waves are fine, but if you need to look at things close or small enough, you need to look at more exact near field calculations instead of far field approximations.
Quantum phenomena occurs because waves only distribute energy on interfering peaks
Except it is near impossible to make a realistic quantum mechanics setup that prevents the wavefunction from spreading out everywhere. Even if there are preferred locations, there is no completely "empty" location between them.
And if you're going to rage arbitrarily against the Higgs boson, might as well against neutrinos and antimatter, other examples of particles being suggested by theory before being directly measured.
If there are waves -- what do they propagate through?...Shouldn't it be proved that there IS NO MEDIUM for waves like light to propagate through?
Why is there a need for a medium? What observational difference does it make if there is a medium or not? Aether theories provided observational differences that could be tested. If there is no observational difference, then science can't provide an answer one way or another.
"point at which a specifically tuned field collapses"
I don't think that is a reasonable description of a photon even in mainstream science.
r than making one band of EM field have a particle and not finding particles in microwaves (for instance)
QM doesn't say this at all, and there is nothing special about any particular band of electromagnetic waves. It would be equally wrong as asking why classical EM says the band of visible light is special, because you can use geometric optics there, but need to treat radio frequencies like waves.
Treating a photon like a particle in QM is an approximation that works really well in some situations, just like treating light like rays in classical EM works really well in some situations but is still in an approximation. And just as how geometric optics gets replaced with quasi-optics, physical optics, or full solutions of the Maxwell's equations depending on how much approximation you can or can't use for a given situation, the particle or wave behavior under quantum mechanics are just approximation for the underlying wavefunctions and you can always default to the wavefunctions if you are going out of regimes where the approximations work.
can someone explain WHY they oscillate back and forth as waves on an ocean do if there is not a medium?
Because Maxwell's equations seem to work, and they allow for oscillation from the inherent nature of electromagnetism. If that answer is not satisfactory, realize that for any model or theory of reality, you can keep asking, "Why?" and at some point reach a statement for which the answer is, "Because that is the way it looks like things work." You can try adding another layer to explain things, but if it doesn't provide any testable changes and adds complications, you haven't gained much if anything.
Anyway, I'm frustrated because I can conceptualize most of what is said in Quantum Mechanics, and other than the math
This sounds like someone saying they can understand a book without reading it. Maybe you're right, but you can't really check, just like a person who's read a book can actually check to see it says the words they think it does. A lot of people who can do the math have complained of how difficult it can be to conceptualize, and that while small sections can be conceptualized, they ultimately involve analogies that fail.
Considering the difficulty you are having with wave-particle duality and other things, maybe you can't conceptualize things as well as you can. As for example, there is no issues or paradoxes with the wave-particle duality when it comes to evaluating the math.
It means that EITHER; each particle has it's own relativistic space/time or motion takes place in a higher and lower dimensional group.
Relativity is completely self-consistent in the former case, that inertial frames are described for each location and velocity, and you can freely transform from one to another with a change of coordinates.
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 be true, much less any resistance.
Perhaps you use the word differently, but I'm not aware of any formal definition. (Dictionaries don't count, as they are never precise enough when talking about physical phenomena.)
I think we've pushed this "anyone can grow up to be president" thing too far.
Aether described a medium in space, not space itself. The whole reason the idea was created was because they thought light couldn't travel through the vacuum of space.