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  #1  
Old 11-04-2017, 08:08 AM
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Dark energy... illusion or not?

Interesting read:
http://www.sciencemag.org/news/2017/...illusion-12136

Last edited by bojan; 11-04-2017 at 08:09 AM. Reason: more info
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  #2  
Old 12-04-2017, 10:13 AM
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Fascinating! It would be nice to be able to explain away dark energy in terms of inhomogeneities within the universe and known physics.

I wonder to what scale we really have to go to assume the universe is homogeneous. With known galactic filaments and huge structures such as the Sloan Great Wall, our observable universe isn't all that homogeneous.

Thanks for the post, Rob
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  #3  
Old 13-04-2017, 07:16 AM
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Hm, I fundamentally agree dark energy doesnt exist but for differing reasons. This acceleration of the universe has never sat well with me with how its "proven" with recent observations of ever older galaxies, which to me they are just seeing back in the past when accelaration from the "big bang event" would have been greater than now as I'd expect.

A lot of all this relies on measurements and constants that I feel are not accurate enough yet either, just too much guesswork going on it seems. Admitedly my maths isnt up to the task of even attempting to understand, let alone work through any of these papers.

I have encountered the assumption that figure rounding has no bearing on a simulation, it still gets you in the ballpark. In a venus transit project I contributed data on I was able to show that the simulation software was rounding a value from two to one decimal places and instead of projecting a straight path for venus across the sun it was an obvious banana curve which was clearly wrong and using actual observation data showed the rounding had to be present in their equation values even though it shouldn't have had any appreciable difference.

So I expect someone will take the time to review from scratch how to calculate the expansion rate accurately, then take precise data from observations to as good a precision as possible, and likewise to constants (which arent) and run the equations with full values until the very final result. Is there even s single source of truth data set in existance? I know things like the number of stars in a galaxy is an ever shifting estimate so if someone needs that value for a paper what would they use? We need a dataset that people can work through and add to that produces a final "cuurently accurate as of today" value instead of different groups having to redo the entire estimate in isolation every time.
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  #4  
Old 13-04-2017, 02:43 PM
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Quote:
Originally Posted by sil View Post
Hm, I fundamentally agree dark energy doesnt exist but for differing reasons. This acceleration of the universe has never sat well with me with how its "proven" with recent observations of ever older galaxies, which to me they are just seeing back in the past when accelaration from the "big bang event" would have been greater than now as I'd expect.
I tend to lean this way. I like it because it is simple and has more common sense than the introduction of an imaginary friend. Having a simple function of c and G as a function of t seems an elegant solution.


Recent article -> https://www.theguardian.com/science/...soon-be-tested
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  #5  
Old 13-04-2017, 09:45 PM
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Seen this yet?
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Researchers at the University of Waterloo have been able to capture the first composite image of a dark matter bridge that connects galaxies together. The scientists publish their work in a new paper in Monthly Notices of the Royal Astronomical Society.
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  #6  
Old 14-04-2017, 01:15 PM
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We can only go with any postulate on real evidence.

Telescopes are being planned to survey thousands of type 1A supernovae to pin down an expansion curve for our Universe.

The real problem is if you calculate the so called Dark Energy from Quantum Mechanics you end up being out by a factor of 10 to the power of 120!

This is the biggest error in the history of Physics. There has only been 10 to 27 seconds since the big bang.

There will be wild postulations to do with Dark Energy and Dark Matter. Most from uninformed sources.

All that matters is data from measurements or just more experiments.

Dark Energy and Dark Matter in Our Universe seems to be at just the correct level for all of us to even exist.

To me this is self evident! We are here because we are here!

Bert
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  #7  
Old 08-06-2017, 07:46 AM
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Here is a very good talk by Sean Carroll on Dark Matter and or modifying Einstein's General Relativity.

https://www.youtube.com/watch?v=4uogQiH5Yx4

This is a very good talk as well on Quantum Field Theory.

https://www.youtube.com/watch?v=gEKSpZPByD0

The Universe consists of Quantum Fields rather than particles.

Bert
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  #8  
Old 10-06-2017, 06:09 AM
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This post reports on a recent paper that offers some verification of the emergent gravity hypothesis.

https://darkmatterdarkenergy.com/201...ndes-proposal/

Margaret Brouwer's check of galaxies is not the final word in the saga, but it does provide some evidence that the dark matter solution to galactic rotation velocity curves might not be the right answer.

Regards,
Tony Barry
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  #9  
Old 19-06-2017, 12:48 PM
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Quote:
Originally Posted by tonybarry View Post
This post reports on a recent paper that offers some verification of the emergent gravity hypothesis.

https://darkmatterdarkenergy.com/201...ndes-proposal/

Margaret Brouwer's check of galaxies is not the final word in the saga, but it does provide some evidence that the dark matter solution to galactic rotation velocity curves might not be the right answer.

Regards,
Tony Barry
WSAAG
Arxiv paper is here.

However... there are other opinions:
https://www.technologyreview.com/s/4...nt-phenomenon/
http://physicsfromtheedge.blogspot.c...gravity-1.html

Last edited by bojan; 19-06-2017 at 01:11 PM.
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  #10  
Old 19-06-2017, 07:17 PM
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Thank you Bojan for the links. I read Mike McCulloch's brief posts and was intrigued. As he says,

Quote:
The variant of inertial-MoND was an inspiration to me, but MoND and MiHsC differ in their predictions and also in that MoND is only an empirical 'fit': it has to be fitted to the data by hand with a constant a0, and there is no physical reason given for it, whereas MiHsC is based on logic, has a good physical reason and predicts well without any arbitrary fitting. This is a profound advantage.
It's a good time to be alive, these problems are being looked at harder and harder than ever before. Something's gotta give.

Regards,
Tony Barry
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  #11  
Old 04-07-2017, 02:33 PM
sil
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Originally Posted by tonybarry View Post
It's a good time to be alive, these problems are being looked at harder and harder than ever before. Something's gotta give.

... but maybe not provably in our lifetimes. Some observation I read about dont take into account their observed events in time only in distance, which to me takes me to different conclusions than they come to. I think we're in a transition period and some people need to relax and be patient (ie media) for results to be examined and peer reviewed before making press announcements and hyped promises on the return/meaning. I dont think we yet have the precision in many tools to make the correct measurements. Instead we are building tools that can find "something" then the next project comes along with an alternate tool/method and finds the same something. They can then start to calibrate and refine off each other to get a tool that can take confident measurements with certainty about what the "something" actually is. Then another project will see how to build on that to find/measure another something. All the way the tools are refining so are the theoretical models to build the full picture to explain it all. Its a little uncomfortable our current best model is one that is aesthetically pleasing and we are working to explore the gaps that have yet to be observed, we haven't yet got all the pieces of the jigsaw, just the picture on the box and hunting for the pieces to fit. Somewhat sloppy I guess but the bottom line we are making observations and collecting data which is key. Eventually we'll have an understanding that allows us to look back on our old data and understand the hidden signal better. We've seen it already after LIGO published, people were able to use that to examine their old data and recognise the signal that was there all along.

Good to see progress in science at least even if the Australian Government isnt too keen on fostering it. Will we survive as a species though to understand enough science for technology to save us.
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  #12  
Old 09-08-2017, 09:32 PM
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Weltevreden SA (Dana)
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Is the evidence for dark energy flimsy?

Many seem to think so, but one notes the absence of any supporting in-depth studies to back up the doubts.

If one is to doubt dark energy, the science support has to be at least on the level of this presentation, which is the state of our knowledge on the matter today.

=Dana in S Africa
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  #13  
Old 10-08-2017, 05:12 PM
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Not that my opinion counts for zip but I believe they are going down the wrong street.
GR rules and its hard to throw but observations are bent to fit in my view.
We are convinced the universe is expanding but is it really? Personally I think steady state makes more sence but I have no qualification so my view is only crack pot and I have no problem with being crack pot but I await a better model than GR even if that is worse than saying I don't believe in God.
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  #14  
Old 17-08-2017, 08:48 AM
sil
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Originally Posted by luka View Post
image of a dark matter
Contradiction in terms. Its a worrying trend that there is a lot of pictures of new things being released to "prove" something new and exotic just because they can make a plausible story to explain or they ignore the papers before hand. Just like the value of the Higg's "absolutely HAD to be only one of two energy values to prove it exists, but the lhc found something at a third value instead not the two precise ones it had to be and still declared it the higgs anyway.
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  #15  
Old 17-08-2017, 08:54 AM
sil
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Not that my opinion counts for zip but I believe they are going down the wrong street.
GR rules and its hard to throw but observations are bent to fit in my view.
We are convinced the universe is expanding but is it really? Personally I think steady state makes more sence but I have no qualification so my view is only crack pot and I have no problem with being crack pot but I await a better model than GR even if that is worse than saying I don't believe in God.
I'm radical and think its neither, that it is slowing down as it should. But I also have an idea how it could expand faster (though I believe thats a misinterpretation of the observations). Maybe one day I'll have my skills up to scratch to try exploring the data and equations for myself which I'm not qualified to do. On the other hand I also have a good case for time travel being possible into the past and how the existence of the bible itself is proof it has happened. and people wonder why scientists are presented as crackpots in movies.
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  #16  
Old 17-08-2017, 09:22 AM
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I have no skill and less education but I know I am right

That's a good start to be a crack pot.

It is unfortunate how scientists are represented in my view they don't deserve such.

Although TV shows like CSI have done wonders for presenting a better image.

Alex
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  #17  
Old 02-10-2017, 05:01 PM
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If anyone wants to consider an alternate model of gravity that does away with dark matter, read about an old professor of mine from Flinders, Professor Reg Cahill, and his process physics model. Youtube him for endless videos of him talking about the "cult of Einstein".
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  #18  
Old 02-10-2017, 07:29 PM
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If anyone wants to consider an alternate model of gravity that does away with dark matter, read about an old professor of mine from Flinders, Professor Reg Cahill, and his process physics model. Youtube him for endless videos of him talking about the "cult of Einstein".
A crack pot no doubt...to even suggest that another model is possible will bring that sort of condemnation. And if he refers to a "cult of Einstein" he probably found it hard to find work.

It will be a long long time before another model of gravity gets up...for many reasons..first its not easy to replace a model..a new model must not only do what the old model did but needs to do it better and then some..perhaps solve problems the old model could not.... and if one hints at an eather or ether well forget it... I think an eather is taboo because that would provide one frame of reference and to do that would sink Special Relativity and as would follow General Relativity... and secondly another model may well sink the Big Bang and that wont happen unless the all the current supportors are all dead and totally new blood is sucessful in presenting a new model.

And remember the model having the Earth at the center of the Solar System is still a good scientific model even if not presenting the reality but in so far as that model can make good and reliable predictions.



Personally I would like to see a model that works with no need for a substance that we can only determine is there by our current model of gravity. We cant see it or measure it other than using our current model of gravity...

Its seems circular and I bet the discovery of something like dark matter in other models would send those other models down the shute. The predictions of GR did not tell us what we found the gallaxies doing... failed prediction means failed theory usually...like inflation to the Big Bang Dark Matter is the saviour of GR.

Even Vera Ruben said way back that she would rather see a change in the maths rather than a new particle.. I read that in an astronomy magazine but I cant find now any record of her ever having offerred such an opinion so maybe the journalist misreported her.

But there is much to support GR and so it is reasonable that it is the model we follow but it seems the establishment or the system will make it very difficult to put up a new model.

I like the idea of an eather, it is hard to know what we should call what must float around in space..all the particles and energy from everywhere going to every place...I also dont like the big bang..it says nothing about the creation of the Universe admittedly and only the evolution of the Universe but really to me it parrallels the creation required by many religions even if it actually does not specifically deal with moment of creation.

I dont like the inflation theory ( without which or a suitable replacement the Big Bang Theory would be dead in the water...Big Bang was dead in the water and it was the theory of inflation that saved it) and so find the concept impossible to accept.

But as I can not offer a better model for gravity or a better model for "the evolution of the Universe" ( nor has anyone else) and so at the present the Theory of Special Relativity and the Theory of General Relativity and as follows the Big Bang Theory are our best models and strangely I respect that.... but I do hope one day the need for dark matter is done away with I find it most uncomfortable that so much of our Universe can not be detected except by our current gravity model.

But what I think does not matter and that is probably the best news you will hear today.

Having said all that it is funny that most of my reading is about Big Bang, Black Holes, Dark Matter and Dark Energy. Fortunately not being a scientist I can think what I like even whilst others (scientists) can see that I am wrong.

Now in the interests of discussion it would be nice for someone to come on and point out how wrong I am...Steven?

alex
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Old 03-10-2017, 11:51 AM
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Quote:
Originally Posted by xelasnave View Post
I have no skill and less education but I know I am right

That's a good start to be a crack pot.

It is unfortunate how scientists are represented in my view they don't deserve such.

Although TV shows like CSI have done wonders for presenting a better image.

Alex
How are scientists represented and in which medium?

My issue with the general population of scientists is their abandonment of fundamental research and risk taking whilst embracing the short term corporate demands for trivial efficiency gains and profit margins.

The bulk of the world's scientists have essentially become corporate puppets straight-jacketed to deranged corporate demands. There are exceptions, but usually these rogue scientists are hidden in Academia or even within the large corporate Goliathical structures.

Considering that there are over 18 million scientists and engineers in the USA alone, and that China has a conveyor belt of 600,000 scientists & 1 million Engineering graduates every year, the global environment for vibrant and genuine R&D that isnt politically and corporately contaminated is pathetically paltry.

Most Scientists should apologise before accepting their degree at graduation and when accepting their first puppet job

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Old 03-10-2017, 12:59 PM
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How are scientists represented and in which medium?

My issue with the general population of scientists is their abandonment of fundamental research and risk taking whilst embracing the short term corporate demands for trivial efficiency gains and profit margins.

The bulk of the world's scientists have essentially become corporate puppets straight-jacketed to deranged corporate demands. There are exceptions, but usually these rogue scientists are hidden in Academia or even within the large corporate Goliathical structures.

Considering that there are over 18 million scientists and engineers in the USA alone, and that China has a conveyor belt of 600,000 scientists & 1 million Engineering graduates every year, the global environment for vibrant and genuine R&D that isnt politically and corporately contaminated is pathetically paltry.

Most Scientists should apologise before accepting their degree at graduation and when accepting their first puppet job

Hi Peter its so nice to have you contribute.

I think my comment re scientists are "represented" probably is a poor choice of words.

It is my impression they get bad press and I failed to point out that I work only with an impression.

Their image comes to us in many ways none of which necessarily represent any form of reality.

Look how the resident scientist is presented on The Simpsons ...not particularly flattering...and although only a cartoon show dripping with satire how must such a presentation subtely work on minds to have folk think scientisits are sort of nutters like the Simpsons character.

There are many movies that present a scientist in a similar way and although fiction I feel many form their views from the Hollywood representation of a scientist.

Another show The Big Bang Theory I feel may peresnt scientists unfairly and unrealistically. I raised that in a post a long time ago but many dont feel the same way as I do on this aspect but I can not see how that show helps the image of a scientist.

They, scientists, are seen as the enemy by many who have religious views it seems to me. Look at the flat rejection by many religious folk of the concept of evolution for example.

Clearly scientists work with facts, observation and well thought out ideas rather than submit to being slaves to a superstitious and unsupported view of the world.

There are those who reject their, scientists, work simply because it fails to fit their view of the world as provided to them in their one religious book.

That in my view is unreasonable and in fact most objectionable.
These folk hold their "book" as authority when clearly all that it contains is merely the writting of someone from uninformed times trying to make sence of what is around them.

I find it strange that their, religious folk, cosmology is picked out of thin air with nothing in support by way of observation...who saw you know who create a damn thing..I doubt if any human was present to observe creation and yet it becomes presented as fact....no one picks up on the small fact no one was there who could write down what happened.


There are those who reject their work because their findings on various matters conflict with a held personal opinion. I think many who reject climate science work that way.

I am guilty here to a degree when I say I dont like the concept of the big bang theory because I can not accept inflation as presented in the theory as one for example.

I speak armed only with a personal impression but in my defence I have the sence to understand that about myself such that I dont take myself too seriously.

My impression is they, scientists, are represented or rather presented in an un necessaryily poor light... I am stuck for more examples but given I speak of an impression I see no need to try to justify or support my impression.



But really there is little need to focus upon my uninformed ramblings.

In truth I dont know really what scientists do or how the game works so anything from me is of no consequence.

Its seems you do not hold scientists in the high regard that I do but I expect each of our opinions will only ever be generalisations based on perhaps very limited experience relative to the vast number of scientists in the world.

I see no need for them to offer any appology when accepting their hard earned degree and find it curious that you think that way. One works hard for a degree firstly and secondly I see no point in holding individuals to account for a perceived problem with the whole group.

Again nice to hear from you and I hope all in your world is wonderful.

alex
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