Evidence that the key assumption made in discovery of dark energy is in error • Hacker News Board

Re: Evidence that the key assumption made in discovery of dark energy is in error

#271

Post by cthalupa » Wed, Jan 08, 2020, 10:54 PM UTC

ltbarcly3 wrote: post #266

cthalupa wrote: post #202

Earlier quoted context omitted.

>Doubling down, they waved their hands and said that conservation of energy must not hold at 'cosmological scales' Energy not being conserved has been experimentally verified, as noted in the article you were linked. This isn't a controversial topic, nor is it one where scientists have proposed it as a potential solution for a problem they can't conclusively solve. GR predicted it, we've verified it. >without any evi…

The example in the article is the exact thing that has been thrown into doubt. This entire thread is because a researcher has found evidence that contradicts the only evidence we have for expansion. I said of course there isn't expansion, the evidence is poor for it and that poor evidence is now disputed, plus expansion means a violation of energy conservation. You come back with "look at the article, energy conserva…

You're totally misunderstanding this whole thing, unfortunately. I don't really know how to do a point by point rebuttal of every line here since each one is building on top of that misunderstanding.

This article calls into question whether or not the expansion of the universe is accelerating - it does not call into question whether or not it is expanding. There is basically zero scientific debate on whether or not the universe is expanding - the evidence that it is huge.

We know that light redshifts. We can observe it. It is experimentally verified. That means that we have verified that energy is not conserved.

Dark energy is not required for the universe to expand and we knew that the universe was expanding long before we had any idea that it (might/might not) be expanding at dynamic rate.

It is possible that our key indicator about the expansion accelerating was in error. It is not at all remotely an indicator that expansion is not happening.

We have known the universe was expanding since 1929. Mountains of evidence have been piling up further confirming it ever since then. It wasn't until the 90s that we found evidence that that expansion was accelerating, and that is what ultimately lead to the hypothesis of dark energy.

In fact, this new research wouldn't even be usable without taking into account expansion, and uses Cepheid variable stars as the control to figure out where we might have gotten things wrong when measuring supernova in distant parts of the universe. The Cepheid variable stars are exactly how we figured out the universe was expanding in the first place.

And, to be clear, there's other evidence for dark energy, including the CMB and how galaxies cluster when we look at things on very very large scales. This is hardly a case of nailing up the coffin for dark energy, but if it pans out this is all accurate, it does call things into question. But it does not cast any doubt on if the universe is expanding, on light redshifting, or the idea that energy isn't always conserved - without those things being accepted as true this research couldn't even exist.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#272

Post by cthalupa » Wed, Jan 08, 2020, 10:57 PM UTC

ltbarcly3 wrote: post #268

mr_mitm wrote: post #156

Earlier quoted context omitted.

Please read this and let me know if you are still convinced that energy must be conserved in General Relativity: https://www.preposterousuniverse.com/blog/2010/02/22/energy-... (edit: Nevermind, this is the same content as the Discovery article linked above, except with better formatting). In short: conservation of energy is a result from the Noether theorem, which says it must be conserved iff the laws of physics ar…

You are using circular reasoning. Energy is not conserved if the universe is expanding. I am saying of course that isn't happening, the evidence for expansion is poor and now has been shown to be unreliable. Without expansion energy is conserved. The example from your article is expansion, which it assumes to be a fact based on the poor evidence that is now invalidated.

I covered this in more depth in my other comment, but quite simply, your entire premise here is wrong.

This research was about whether or not the expansion of the universe is accelerating, and it casts some doubt on our belief that it is. It does not invalidate all of the evidence, potentially just that of measuring supernovas.

Not only does this research not cast doubt on whether or not expansion is occurring, it would be nonsensical and couldn't exist in a meaningful way without taking expansion as a fact.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#273

Post by igravious » Wed, Jan 08, 2020, 11:18 PM UTC

cygx wrote: post #257

igravious wrote: post #249

Earlier quoted context omitted.

Don't take this the wrong way. If you can't explain what's in your head in plain English in answer to a question that was asked in plain English then there's not much point in answering. I'm not getting the impression that you've answered my question, I'm getting the impression that you don't know how to answer my question.

I'll try again: General relativity comes with a generic mechanism to compute frequency shifts. We don't need to try to figure out whether or not the effect is due to time dilation or spatial expansion, we can just do the math. But if we're lucky, we can find a way to split up space and time that allow for such intuitive interpretations. However, that's window dressing, so to speak. All this assumes that the spacetime…

Much better!

Now, if there is a failure to understand your answer the reason why lies with me :)

Re: Evidence that the key assumption made in discovery of dark energy is in error

#274

Post by ncmncm » Thu, Jan 09, 2020, 1:09 AM UTC

ltbarcly3 wrote: post #267

ncmncm wrote: post #242

Earlier quoted context omitted.

Conservation of energy can never be more than a collection of observations. Elevate it to a principle, and you're not doing science anymore, you're doing religion. But not a fun one.

All of science is just a collection of observations combined with attempts to find patterns in those observations. Read up on Hume, Inductive Reasoning. There is no fundamental grounding for the idea that what any of the rules we observe the universe following won't change suddenly for no reason apart from the fact that we have never seen it happen.

Inductive reasoning works reliably in mathematics and formal logic, and literally nowhere else. So, if you have a mathematical model of physics, you can use inductive reasoning on that model, but the universe is under no obligation to obey your model.

In fact, we have found our models to be violated by nature over and over, countless thousands of times. Quantum field theory and General Relativity arose specifically to address exactly such violations of older models. Nobody has found violations of either (unless it finally turns out there isn't actually dark matter).

Dark energy and its lack happen to be both consistent with GR. GR and QFT are not consistent with one another, so one or both will need to give, but each has thus far passed every actual test.

You may insist that red shift is not caused by universal expansion, but then you need another explanation for it, consistent with observations. Discomfort is not such an explanation.

Your religion is not fun.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#275

Post by ncmncm » Thu, Jan 09, 2020, 1:34 AM UTC

AnIdiotOnTheNet wrote: post #214

ncmncm wrote: post #29

Haha, called it! Feynman warned about this specific phenomenon: basing new physics on the points at the extreme end of your graph, where the measurements are least reliable. In this case, these points correspond to demolition of the most distant and youngest stars in the sample, which could differ in many ways from the common, much more recent events. Low metallicity is a difference that is obvious to every AP, but t…

> Haha, called it! One or two years from now I invite you to take a look back at this comment and see if you still feel so smug. This is a relatively recent paper, give it some time to be chewed up and spit out by the cosmological community before hailing it as the deathknell of a decades old tricky problem.

I will happily eat crow if they find reliable independent corroboration of the actual distance of these events. That will not be easy. The universe has many ways to adjust the relative brightness of photons at different wavelengths on a common path, and many ways to vary the relative brightness when they are emitted.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#276

Post by briantakita » Thu, Jan 09, 2020, 1:48 AM UTC

briantakita wrote: post #269

tsimionescu wrote: post #261

Earlier quoted context omitted.

When you look at pictures like [1] it's very hard to accept a kind of galactic-cluster level atmosphere that would produce that type of lensing. You're also ignoring the observed clock differences between clocks in LEO and clocks on the ground - which happen to have the exact values predicted by GR. And these are just some of the more neatly observable consequences of GR. There are many others that are more sophistic…

To your point about throwing out the baby with the bathwater, here is the strength of the EU argument: "The EU community is a challenger to the standard gravitational model, believing space-time to be a misinterpretation of the Universe. The things we see in the Universe – from large scale filamentary structures connecting galactic clusters, to Earth’s climate and meteorology – are plasma phenomena driven by electrom…

To your point re: supplementing experimentally backed systems (i.e. Newtonian Mechanics):

"...what is really wanted for a truly Natural Philosophy is a supplement to Newtonian mechanics...and introducing the additional facts, chiefly electrical - especially the fact of variable inertia - discovered since his time..."

"...it may be that when the structure of an electron is understood, we shall see that an 'even-powered' stress in the surrounding aether is necessarily involved. What I do feel instinctively is that this is the direction for discovery, and what is needed is something internal and intrinsic, and that all attempts to explain gravitation as due to the action of some external agency, whether flying particles or impinging waves, are doomed to failure..."

-- Sir Oliver Lodge - Nature, Feb 17, 1921

Re: Evidence that the key assumption made in discovery of dark energy is in error

#277

Post by tylerjwilk00 » Thu, Jan 09, 2020, 4:07 AM UTC

eloff wrote: post #264

BoiledCabbage wrote: post #181

Earlier quoted context omitted.

What's more mind-boggling to me is all these thousands of scientists running around looking at the extreme oddity of multi-dimensional string theory, and nobody bothered to check if the cosmological constant is actually real. It seems like physics is really being held back by perverse incentives. And of course my pocket view that string theory will turn out to be the single largest waste of brilliant human minds in h…

I'm not a physicist, but I don't think string theory is a total waste. It agrees with our existing theories and predictions, so it can be viewed as just an alternative mathematical abstraction, and there is value in that. Whether or not tiny vibrating strings are really at the heart of things is neither here nor there. It's about as relevant to science as god.

The problem with string theory is that there are limitless physics universes you can create within its framework so saying that ours fits in it is not saying a lot. Many universes could be described by it.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#278

Post by tylerjwilk00 » Thu, Jan 09, 2020, 4:22 AM UTC

rs23296008n1 wrote: post #252

tiborsaas wrote: post #177

Earlier quoted context omitted.

Dark matter is definitely not a rounding error [0]. There are multiple evidence for strong gravity effects where we just don't see the required matter the explain the observed phenomenons [1][2] [0] https://www.forbes.com/sites/briankoberlein/2016/09/23/rotat... [1] https://en.wikipedia.org/wiki/Bullet_Cluster#Significance_to... [2] http://cosmology.berkeley.edu/Education/CosmologyEssays/Grav... Briefly, dark matter…

I'm feeling verbose. So here we go. Dark matter: Maybe something that we'll one day make lunch boxes out of. Maybe also a rounding error. Of some sort. In some way. You haven't got the mountain-of-data yet. A lot-of-data is a good start. This doesn't mean the missing matter isn't some super-energy infused version of something we already know about. For all we know, its simply "ordinary" matter we'd otherwise already…

Unicorns are real. They're just call by a different name, Elasmotherium sibiricum [1], a now extinct species of rhinoceros that shortly co-existed with man.

[1] https://www.google.com/search?q=Elasmotherium+sibiricum&tbm=...

Re: Evidence that the key assumption made in discovery of dark energy is in error

#279

Post by tsimionescu » Thu, Jan 09, 2020, 7:47 AM UTC

briantakita wrote: post #269

tsimionescu wrote: post #261

Earlier quoted context omitted.

When you look at pictures like [1] it's very hard to accept a kind of galactic-cluster level atmosphere that would produce that type of lensing. You're also ignoring the observed clock differences between clocks in LEO and clocks on the ground - which happen to have the exact values predicted by GR. And these are just some of the more neatly observable consequences of GR. There are many others that are more sophistic…

To your point about throwing out the baby with the bathwater, here is the strength of the EU argument: "The EU community is a challenger to the standard gravitational model, believing space-time to be a misinterpretation of the Universe. The things we see in the Universe – from large scale filamentary structures connecting galactic clusters, to Earth’s climate and meteorology – are plasma phenomena driven by electrom…

The problem I have with assuming plasma is pervasive in the void of space is that, unlike the hypothesised dark matter, plasma should be hot and visible. As I understand it, there is mainstream acceptance that there is a possibility that some regions of space, such as the galactic center, could contain plasma (though the preferred explanation is that they contain matter pulled apart by a supermassive black hole), and some other regions such as nebulae do contain plasma, but the picture I linked earlier doesn't show any kind of hot visible substance that could refract light to produce that lensing effect.

If gravity affected the atomic clock frequency, we would need to understand how. Either way, we know from observations of the speed of light being constant in any reference frame that time dilation must exist when moving at high speeds. GR incorporates acceleration and gravity here.

Note that rejecting GR doesn't get rid of space-time (perhaps at best, it gets rid of curved space-time). We know from very good observations that the speed of light is a physical constant, so at least special relativity must be true (or we need some other theory to explain this physical phenomenon).

However, if we got rid of GR we would also need a new explanation for a very old problem: why is an object's inertial mass (the amount that it opposes motion) equal to its gravitational mass (the amount that it is attracted by the earth through Newton's formula)? GR has a beautiful unification of these two masses, making acceleration equivalent to gravity (which also happens to match how we feel, by the way).

Now, if I understand correctly, Plasma Cosmology does not discount GR, but simply proposes that plasma physics is more important in some galactic structures, especially the large-scale structure of the universe. There seem to be some technical limitations (related to implications for the state of the early universe vs observed current state), but perhaps they are resolvable.

Electric Universe starts from there essentially and seems to go much farther, getting rid of gravity and GR (and Special Relativity?) and hits all of the issues I mentioned above.

Re: Evidence that the key assumption made in discovery of dark energy is in error

#280

Post by tsimionescu » Thu, Jan 09, 2020, 7:51 AM UTC

briantakita wrote: post #276

briantakita wrote: post #269

Earlier quoted context omitted.

To your point about throwing out the baby with the bathwater, here is the strength of the EU argument: "The EU community is a challenger to the standard gravitational model, believing space-time to be a misinterpretation of the Universe. The things we see in the Universe – from large scale filamentary structures connecting galactic clusters, to Earth’s climate and meteorology – are plasma phenomena driven by electrom…

To your point re: supplementing experimentally backed systems (i.e. Newtonian Mechanics): "...what is really wanted for a truly Natural Philosophy is a supplement to Newtonian mechanics...and introducing the additional facts, chiefly electrical - especially the fact of variable inertia - discovered since his time..." "...it may be that when the structure of an electron is understood, we shall see that an 'even-powere…

I'm not sure what this quote is meant to illustrate. The structure of the Electron is now understood in QM (it is structure-less, an elementary particle), the luminiferous aether is disproven, and gravity is understood as equivalent to acceleration, essentially through E=mc2, instead of being carried by particle or wave (though it can cause waves, as recently detected). On the other hand, other fields, such as the electrical field, are shown to reduce to particles flying around (photons, for the electric field), so if the quote was meant to say that electrical charge could replace a graviton, that has proven wrong.