U think that the univers is realy expanding? think again

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Discussion Overview

The discussion centers around the expansion of the universe and the role of neutrinos, particularly in relation to their mass and implications for cosmological models. Participants explore the connection between neutrino mass, dark matter, and the validity of the Big Bang theory, with references to recent experimental findings and theoretical postulations.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant questions the expansion of the universe, suggesting that if neutrinos have mass, it could imply a contracting universe and challenge the Big Bang theory.
  • Another participant asserts that neutrinos have been confirmed to have mass and argues that this does not affect the current understanding of the universe's expansion, which is accelerating due to dark energy.
  • Some participants emphasize that the mass of known neutrinos is too small to significantly impact cosmological models, particularly in explaining dark matter.
  • A later reply discusses the postulation of a heavy fourth generation neutrino to address issues in cold dark matter models, referencing specific studies.
  • There is a debate regarding the reliability of Wikipedia as a source for information on neutrinos, with some participants expressing skepticism about its accuracy.
  • Participants discuss the implications of recent experiments, such as MiniBooNE and LSND, on the existence of sterile neutrinos and their relevance to dark matter, noting conflicting interpretations of findings.

Areas of Agreement / Disagreement

Participants express differing views on the implications of neutrino mass for the expansion of the universe and the validity of the Big Bang theory. There is no consensus on the reliability of certain experimental findings or the interpretations of those findings regarding sterile neutrinos and dark matter.

Contextual Notes

Some claims rely on specific experimental results that may not be universally accepted or interpreted consistently. The discussion includes references to various studies and articles, which may have differing levels of credibility and relevance.

darkness_limits
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u think that the universe is really expanding?? think again

well i readed recently in a physics magazine that the scientist are trying to find if the neutrino has any mass , if it is true then the universe will be contracting and not expanding and the big bang theorie is false.. what is the relation ?
 
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Er... you are about 10 years too late. We ALREADY know the neutrinos have mass! The neutrino oscillation experiments have been going on for the past 10 years, at least. This has no effect on the universe expansion as of yet. In fact, the whole reason for the "dark energy" scenario is due to the more recent observation that the universe seems to be expanding at an even faster rate than expected!

Zz.
 
Even worse, the neutrino 'mass' is far too insignificant to affect the 'big picture' of expansion. It is not a viable candidate to explain 'dark matter' or assert it's place as the 'missing mass' in a Lamda universe.
 
Chronos said:
Even worse, the neutrino 'mass' is far too insignificant to affect the 'big picture' of expansion. It is not a viable candidate to explain 'dark matter' or assert it's place as the 'missing mass' in a Lamda universe.
This is correct. I would like to emphasize that the mass of the known neutrinos is too insignificant. However, the existence of a heavy fourth generation neutrino has been recently postulated in order to correct the too cuspy density profiles of a pure cold dark matter model. See for example: Constraining Warm Dark Matter candidates including sterile neutrinos and light gravitinos with WMAP and the Lyman-alpha forest.
 
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hellfire said:
This is correct. I would like to emphasize that the mass of the known neutrinos is too insignificant. However, the existence of a heavy fourth generation neutrino has been recently postulated in order to correct the too cuspy density profiles of a pure cold dark matter model. See for example: Constraining Warm Dark Matter candidates including sterile neutrinos and light gravitinos with WMAP and the Lyman-alpha forest.

Er.. are you sure? I thought the recent http://physicsworld.com/cws/article/news/27569 kinda dashed that hope?

Zz.
 
You might be right. I was relying on the wikipedia article about MiniBooNe that claims that there are indications pointing towards the existence of the sterile neutrino and that this information is more recent than the april paper also mentioned there (and that I assume to be the source for the physicsworld article you have linked). However, I've checked now the MiniBooNe web and I was not able to find any more recent information. It seams that the wikipedia article is not very accurate.
 
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hellfire said:
It seams that the wikipedia article is not very accurate.

That goes without saying.

Trust Wikipedia at your own risk.

Zz.
 
The quality of articles on Wiki vary wildely, and daily. It is an unreliable source, IMO.
 
ZapperZ said:
Er.. are you sure? I thought the recent http://physicsworld.com/cws/article/news/27569 kinda dashed that hope?

Zz.

Not really. The LSND signal that MiniBooNE was trying to reproduce is in the wrong region of the sterile neutrino parameter space to account for warm dark matter.
 
  • #10
But even LSND has backed down from its own findings when it couldn't find it again, no? Or am I thinking of another experiment here?

Zz.
 
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  • #11
ZapperZ said:
But even LSND has backed down from its own findings when it couldn't find it again, no? Or am I thinking of another experiment here?

Zz.

My point was that MiniBooNE does not rule out the full parameter space for sterile neutrinos. The big news back in April was that it had found nothing where the hint of a signal reported by LSND had been. This is in a region of the parameter space quite remote from any sort of dark matter candidate.
 

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