| Topic: |
Science > Physics |
| User: |
"Sam Wormley" |
| Date: |
06 Feb 2004 02:16:37 PM |
| Object: |
UK Physicists attack cosmological model |
Ref: http://physicsweb.org/article/news/8/2/4
Physicists attack cosmological model
6 February 2004
Many astronomers believe that the universe is dominated by cold 'dark
matter' and 'dark energy' - a view that has been confirmed by recent
measurements on the cosmic background radiation. Now, however, a group
of astrophysicists in the UK has found that this radiation - the
microwave 'echo' of the big bang - may in fact have been modified or
'corrupted' as it passed through galaxy clusters on its way to Earth.
The result could undermine previous evidence for both dark matter and
energy (Monthly Notices of the Royal Astronomical Society 347 L67;
http://arxiv.org/abs/astro-ph/0306180)
The cosmic microwave background provides a picture of the universe as
it was some 400 000 years after the big bang. By this time, the
universe had cooled down enough for atoms to form, which means that
there were no longer any free electrons to scatter the photons
produced in the early universe. Any variations or anisotropy in the
temperature of the background radiation therefore reflect variations
in the density of the universe at this time.
These temperature fluctuations can be expressed as a sum of spherical
harmonics, and astrophysicists plot the relative strength of these
harmonics as a function of angle. The height and positions of the
peaks in this so-called 'power spectrum' are related to basic
astrophysical properties of the universe.
Data from the first year of NASA's Wilkinson Microwave Anistropy Probe
(WMAP) satellite - unveiled in February 2003 - support the currently
popular concordance model of the universe. This model predicts that
the universe is a cocktail of 5% ordinary matter, 25% undetectable
dark matter and 70% dark energy - the nature of which is unknown.
Now, Tom Shanks and colleagues at Durham University have performed a
new analysis of the WMAP data by looking at positions in the sky where
galaxy clusters are abundant. They found that the positions of these
clusters generally coincided with positions of low temperature in the
microwave background data.
According to the team, this could be because the hot gas in the galaxy
clusters has scattered the cosmic microwave background radiation and
distorted the background spectrum. This so-called Sunyaev-Zeldovich
effect can reduce the temperature of the microwave background and WMAP
physicists themselves have already reported on observing the effect
close to galaxy cluster centres.
Shanks and co-workers now believe that the distortion could extend to
scales of 1 degree on the sky - an area much larger than previously
detected. This would mean that the first and biggest peak in the power
spectrum could be affected. Until now, the Sunyaev-Zeldovich effect
had only been observed near much smaller angles. "Since the first peak
is the one that seems to support a cold dark matter universe, any
problem here could ultimately weaken the evidence for a universe that
contains dark matter and dark energy," Shanks told PhysicsWeb.
The team now plans to search for the effect in more distant galaxy
clusters using further data from WMAP and the Planck Surveyor, which
is due to be launched later this decade.
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| User: ";-Peter Ramsey" |
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| Title: Re: UK Physicists attack cosmological model |
06 Feb 2004 07:13:52 PM |
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"Sam Wormley" <swormley1@mchsi.com> wrote in message > Shanks and
co-workers now believe that the distortion could extend to
"... any problem here could ultimately weaken the evidence for a universe
that
contains dark matter and dark energy," Shanks told PhysicsWeb.
Best news I've heard this week. ;-p
;-Peter
--
Visit the laptop of the Gods
http://www.godchecker.com
mythology with a twist
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| User: "Bruce Scott TOK" |
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| Title: Re: UK Physicists attack cosmological model |
07 Feb 2004 03:09:06 PM |
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|> Ref: http://physicsweb.org/article/news/8/2/4
|>
|> Physicists attack cosmological model
|> 6 February 2004
[SZ effect]
|> Now, Tom Shanks and colleagues at Durham University have performed a
|> new analysis of the WMAP data by looking at positions in the sky where
|> galaxy clusters are abundant. They found that the positions of these
|> clusters generally coincided with positions of low temperature in the
|> microwave background data.
I would have expected the WMAP team to have considered this... must be
pretty embarrassing if the new model has to be rectracted. There has
been a lot more press with this than with the "fifth force" and similar
things.
--
cu,
Bruce
drift wave turbulence: http://www.rzg.mpg.de/~bds/
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| User: "" |
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| Title: OT [Re: UK Physicists attack cosmological model] |
08 Feb 2004 05:32:17 AM |
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In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
/BAH
Subtract a hundred and four for e-mail.
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| User: "Franz Heymann" |
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| Title: Re: OT [Re: UK Physicists attack cosmological model] |
08 Feb 2004 11:35:23 AM |
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<jmfbahciv@aol.com> wrote in message
news:402630fe$0$3180$61fed72c@news.rcn.com...
In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
Yes.
Franz
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| User: "" |
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| Title: Re: OT [Re: UK Physicists attack cosmological model] |
10 Feb 2004 04:40:31 AM |
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In article <c05s0r$i4q$1@sparta.btinternet.com>,
"Franz Heymann" <notfranz.heymann@btopenworld.com> wrote:
<jmfbahciv@aol.com> wrote in message
news:402630fe$0$3180$61fed72c@news.rcn.com...
In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
Yes.
<GRIN> Boy, did I dig my hole with this one. Now I get to
decide if 1. you're answering my first question; 2. you're
being kind and obeying my plea 3. Answering both at the
same time. Decisions, decisions, decisions. I should know
better with all of my old work experience.
Thanks, Franz. I chuckled all day yesterday on this one.
/BAH
Subtract a hundred and four for e-mail.
.
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| User: "Franz Heymann" |
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| Title: Re: OT [Re: UK Physicists attack cosmological model] |
10 Feb 2004 11:46:06 AM |
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<jmfbahciv@aol.com> wrote in message
news:4028c7ef$0$3204$61fed72c@news.rcn.com...
In article <c05s0r$i4q$1@sparta.btinternet.com>,
"Franz Heymann" <notfranz.heymann@btopenworld.com> wrote:
<jmfbahciv@aol.com> wrote in message
news:402630fe$0$3180$61fed72c@news.rcn.com...
In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
Yes.
<GRIN> Boy, did I dig my hole with this one. Now I get to
decide if 1. you're answering my first question; 2. you're
being kind and obeying my plea 3. Answering both at the
same time. Decisions, decisions, decisions. I should know
better with all of my old work experience.
Thanks, Franz. I chuckled all day yesterday on this one.
All right, let me give you some relief:
At the time I spoke, I also saw a 0 line count in the headers whenever Bruce
posted.
I haven't looked recently. He might have been cured of his bad habits by
now.
Franz
/BAH
Subtract a hundred and four for e-mail.
.
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| User: "" |
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| Title: Re: OT [Re: UK Physicists attack cosmological model] |
11 Feb 2004 04:46:44 AM |
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In article <c0b5ct$fmv$2@hercules.btinternet.com>,
"Franz Heymann" <notfranz.heymann@btopenworld.com> wrote:
<jmfbahciv@aol.com> wrote in message
news:4028c7ef$0$3204$61fed72c@news.rcn.com...
In article <c05s0r$i4q$1@sparta.btinternet.com>,
"Franz Heymann" <notfranz.heymann@btopenworld.com> wrote:
<jmfbahciv@aol.com> wrote in message
news:402630fe$0$3180$61fed72c@news.rcn.com...
In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]>
wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
Yes.
<GRIN> Boy, did I dig my hole with this one. Now I get to
decide if 1. you're answering my first question; 2. you're
being kind and obeying my plea 3. Answering both at the
same time. Decisions, decisions, decisions. I should know
better with all of my old work experience.
Thanks, Franz. I chuckled all day yesterday on this one.
All right, let me give you some relief:
At the time I spoke, I also saw a 0 line count in
the headers whenever Bruce posted.
I haven't looked recently. He might have been cured of
his bad habits by now.
He hasn't posted from my POV since then. It's not his bad habit,
but brain-damaged software which seems to be propogating at an
alarming rate these days. I've had too much thinking in other
areas to do and haven't been minding the bit store w.r.t. tracing
bit flows.
/BAH
Subtract a hundred and four for e-mail.
.
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| User: "Richard Herring" |
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| Title: Re: OT [Re: UK Physicists attack cosmological model] |
09 Feb 2004 07:30:41 AM |
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In message <402630fe$0$3180$61fed72c@news.rcn.com>,
writes
In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
He doesn't have a Lines: header at all (which is OK according to
RFC1036, it's not a required item.) It's your software that's
interpreting its absence as zero.
--
Richard Herring
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| User: "" |
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| Title: Re: OT [Re: UK Physicists attack cosmological model] |
10 Feb 2004 04:37:37 AM |
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In article <SkhkAmtBu4JAFwz7@baesystems.com>,
Richard Herring <junk@[127.0.0.1]> wrote:
In message <402630fe$0$3180$61fed72c@news.rcn.com>,
writes
In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
He doesn't have a Lines: header at all
Thanks, I was wonder if the behaviour had to do with his @ in
following angle brackets enclosed in square brackets (a very odd
contstruct in the computing biz).
..(which is OK according to
RFC1036, it's not a required item.) It's your software that's
interpreting its absence as zero.
Fucking software (mine,not his). It hides more ***** that lays
in wait to bite me in the bit.
/BAH
Subtract a hundred and four for e-mail.
.
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| User: "Richard Herring" |
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| Title: Re: OT [Re: UK Physicists attack cosmological model] |
10 Feb 2004 07:12:56 AM |
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In message <4028c741$0$3204$61fed72c@news.rcn.com>,
writes
In article <SkhkAmtBu4JAFwz7@baesystems.com>,
Richard Herring <junk@[127.0.0.1]> wrote:
In message <402630fe$0$3180$61fed72c@news.rcn.com>,
writes
In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
He doesn't have a Lines: header at all
Thanks, I was wonder if the behaviour had to do with his @ in
following angle brackets enclosed in square brackets (a very odd
contstruct in the computing biz).
What, like mine?
(A dotted-quad IP address in square brackets is a perfectly good
alternative to a domain name, and this particular address particularly
so ;-)
--
Richard Herring
.
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| User: "" |
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| Title: Re: OT [Re: UK Physicists attack cosmological model] |
11 Feb 2004 04:43:31 AM |
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In article <VPUVaPVYjNKAFwYd@baesystems.com>,
Richard Herring <junk@[127.0.0.1]> wrote:
In message <4028c741$0$3204$61fed72c@news.rcn.com>,
writes
In article <SkhkAmtBu4JAFwz7@baesystems.com>,
Richard Herring <junk@[127.0.0.1]> wrote:
In message <402630fe$0$3180$61fed72c@news.rcn.com>,
writes
In article <200402072109.i17L96oe001262@ipp.mpg.de>,
Bruce Scott TOK <Use-Author-Supplied-Address-Header@[127.1]> wrote:
Does anybody else see a 0 line count in their headers whenever
Bruce posts? Please say yes; I don't need any more problems.
He doesn't have a Lines: header at all
Thanks, I was wonder if the behaviour had to do with his @ in
following angle brackets enclosed in square brackets (a very odd
contstruct in the computing biz).
What, like mine?
Yea.
(A dotted-quad IP address in square brackets is a perfectly good
alternative to a domain name, and this particular address particularly
so ;-)
Our OS would have problems with such a construct. :-) [emoticon
puts on biased hat] We had sensible rules.
I hadn't paid enough attention to formats and hadn't really worked
on the hypothesis; IOW, I got lazy and decided to just ask instead.
/BAH
Subtract a hundred and four for e-mail.
.
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