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Uh, Oh: BICEP2 Results In Jeopardy?



 
 
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  #1  
Old May 27th 14, 08:17 PM posted to sci.astro.research
Robert L. Oldershaw
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Default Uh, Oh: BICEP2 Results In Jeopardy?

On Tuesday, May 20, 2014 2:10:03 PM UTC-4, Jonathan Thornburg wrote:
Solar neutrino fluxes do not show a 22-year time dependence, so we
know that there is NOT a 22-year solar cycle in the center of the sun
(which is where solar neutrinos are generated). So understanding the
center of the sun doesn't really have much to do with understanding
the solar cycle.


So you think the 22-year cycle within the Sun is unrelated to the deep
inner core of the Sun?

Is there no doubt in your mind about that?

[Mod. note: reformatted -- mjh]
  #2  
Old May 28th 14, 07:18 AM posted to sci.astro.research
Phillip Helbig---undress to reply
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Default Uh, Oh: BICEP2 Results In Jeopardy?

In article , "Robert L.
Oldershaw" writes:

On Tuesday, May 20, 2014 2:10:03 PM UTC-4, Jonathan Thornburg wrote:
Solar neutrino fluxes do not show a 22-year time dependence, so we
know that there is NOT a 22-year solar cycle in the center of the sun
(which is where solar neutrinos are generated). So understanding the
center of the sun doesn't really have much to do with understanding
the solar cycle.


So you think the 22-year cycle within the Sun is unrelated to the deep
inner core of the Sun?

Is there no doubt in your mind about that?


Consider how long it takes a photon to get from the core to the surface
of the Sun. I don't recall the number, but it is 1 million years or
so.
  #3  
Old May 29th 14, 07:44 AM posted to sci.astro.research
Robert L. Oldershaw
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Posts: 617
Default Uh, Oh: BICEP2 Results In Jeopardy?

On Wednesday, May 28, 2014 2:18:37 AM UTC-4, Phillip Helbig---undress to reply wrote:
Consider how long it takes a photon to get from the core to the surface
of the Sun. I don't recall the number, but it is 1 million years or
so.


But I think that electromagnetic and gravitational interactions
between the inner core of the Sun and its convective layers take a
good deal less time than a million years.

Would you not agree? (;-)

[Mod. note: reformatted -- mjh]
  #4  
Old May 29th 14, 07:23 PM posted to sci.astro.research
Jos Bergervoet
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Default Uh, Oh: BICEP2 Results In Jeopardy?

On 5/29/2014 8:44 AM, Robert L. Oldershaw wrote:
On Wednesday, May 28, 2014 2:18:37 AM UTC-4, Phillip Helbig---undress to reply wrote:
Consider how long it takes a photon to get from the core to the surface
of the Sun. I don't recall the number, but it is 1 million years or
so.


But I think that electromagnetic and gravitational interactions
between the inner core of the Sun and its convective layers take a
good deal less time than a million years.


EM? Perhaps you are thinking of an oscillating magnetic
dipole with a frequency of 22 year^(-1), i.e. flipping
every 11 years, which has its source in the center?
But it will have it's field strongly attenuated by the
conducting medium around it. The field changes we are
talking of are now still photons, but with a very low
frequency.

Basically the attenuation length for EM waves applies
here, which is the "skin-depth" in the medium at this
frequency. For EM communication from the center to the
surface we need 10^8 to 10^9m for this skin-depth:
delta = sqrt(2/omega sigma mu)
If we assume mu=mu0 (non-magnetic medium) this is the
same as requiring:
sigma 0.001 [S/m]
But I would expect the plasma to conduct much better
(may astrophysicists here correct me if I'm wrong).

So EM communication would seem to be impossible. And
for the gravitational interaction you mention, you'd
need gravitating density fluctuations in the core, i.e.
quite strong ones. But in that case, shouldn't we also
look at simple pressure waves (sound) as the mechanism?

--
Jos
  #5  
Old May 29th 14, 07:35 PM posted to sci.astro.research
Robert L. Oldershaw
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Default Uh, Oh: BICEP2 Results In Jeopardy?

On Thursday, May 29, 2014 2:44:10 AM UTC-4, Robert L. Oldershaw wrote:


Getting back to the BICEP2 issue, here is a new paper by those who have the expertise to review the current situation.

http://arxiv.org/abs/1405.7351
  #6  
Old May 30th 14, 08:22 AM posted to sci.astro.research
Robert L. Oldershaw
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Posts: 617
Default Uh, Oh: BICEP2 Results In Jeopardy?

On Thursday, May 29, 2014 2:35:36 PM UTC-4, Robert L. Oldershaw wrote:

And here is another discussion of the present status of the BICEP2 claims.

It is low-tech and accessible piece from Nature with interesting
personal comments.

http://www.nature.com/news/no-eviden...-waves-1.15322
  #7  
Old May 31st 14, 01:34 PM posted to sci.astro.research
Nicolaas Vroom
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Default Uh, Oh: BICEP2 Results In Jeopardy?

On Friday, May 30, 2014 9:22:36 AM UTC+2, Robert L. Oldershaw wrote:
On Thursday, May 29, 2014 2:35:36 PM UTC-4, Robert L. Oldershaw wrote:

And here is another discussion of the present status of the BICEP2 claims.

http://www.nature.com/news/no-eviden...-waves-1.15322


In this document we can read:
"That is a problem, because on small scales, gravitational lensing
-- the bending of light due to massive objects -- exactly mimics the
twisting polarization pattern that gravitational waves imprint on
larger spatial scales." (Exactly ?)
That is not only a problem for gravitational wave detection but also
for CMB radiation in general.

The central part of this document
http://www.naturalhistorymag.com/fea...30/dark-matter
shows an image of a galaxy cluster.
At the right hand side we see the Milky Way.
The left side shows a distant galaxy and two virtual galaxy's.
The picture shows one straight line starting from the galaxy cluster
which goes through the galaxy cluster and which ends in the Milky Way.
What you should do is the reverse. Use a laser pen and point the pen
to the center of that cluster. First the light will be a bundle going
straight towards the center but there after the light will be fanned
out in "all" different directions.
For the CMB radiation the same happens but in reverse order.

The issue is: the influence of this noise in order to calculate
the cosmological parameters.
Maybe the original CMB was much more uniform as presently observed.

Nicolaas Vroom
http://users.pandora.be/nicvroom/

[Mod. note: the influence of galaxy clusters on the CMB is well
understood, as I pointed out some time ago -- mjh]
  #8  
Old June 2nd 14, 02:02 PM posted to sci.astro.research
Phillip Helbig---undress to reply
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Posts: 629
Default Uh, Oh: BICEP2 Results In Jeopardy?

In article , Nicolaas Vroom
writes:
On Friday, May 30, 2014 9:22:36 AM UTC+2, Robert L. Oldershaw wrote:
And here is another discussion of the present status of the BICEP2 claims.

http://www.nature.com/news/no-eviden...-waves-1.15322


In this document we can read:
"That is a problem, because on small scales, gravitational lensing
-- the bending of light due to massive objects -- exactly mimics the
twisting polarization pattern that gravitational waves imprint on
larger spatial scales." (Exactly ?)
That is not only a problem for gravitational wave detection but also
for CMB radiation in general.


The key point is "on small scales". BICEP2 was not the first to detect
B-mode polarization. However, previous detection was on smaller scales
and understood in terms of gravitational lensing. BICEP2 looked at
larger scales where the signal won't be from gravitational lensing. (Of
course, as recent discussion shows, this does not automatically mean
that it is from gravitational waves.)
 




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