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Accepted Science?

by Norman
Tags: accepted, science
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Norman
#1
Jun2-06, 09:28 AM
P: 922
Hi all,

I am a particle physicist who deals with transport of radiation through materials. That is to say I am directly involved with the shielding of astronauts from galactic cosmic rays. I came across a paper a paper that said the GCR spectrum may be somewhat responsible for variations in the mean temp. of Earth.
It is a paper by Veizer and Shaviv that looks at geological records and compares them to some models of the GCR spectrum.

My question is, is this considered main stream science? That is to say, has there been any work that refutes this or superceedes it? Has a consensus in the atmospheric and geological realms been reached on the validity of their statements? Admittedly, I have not read the paper in detail, just a quick skim. I will withold any more comments until the people who are more knowledgeable than me in this realm comment.
Cheers,
Ryan
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Bystander
#2
Jun2-06, 02:21 PM
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"Somewhat?" Can't argue with a word like that --- (1/T)dT ~ (1/4q"dot")dq"dot". If they come up with a GCR power density variability of tenths of watts, no one can argue --- it's more rigorous bookkeeping than assuming, "The cosmic ray flux" is insignificant when compared to the solar flux.

Comment on the link: if it's a "subscribers only" site, include a brief summary of the pertinent information, such as "Found a GCR flux of x watt/m2.

Edit: Sorry 'bout the missing "(1/T)" --- now corrected.
Norman
#3
Jun2-06, 05:04 PM
P: 922
Sorry didn't realise it was subscriber only... I could access so I didn't think of it. Still haven't had a chance to read it thoroughly.

The paper can be found for free here (pdf).

Norman
#4
Jun2-06, 05:24 PM
P: 922
Accepted Science?

Here is a good critique of the previous paper.
Rahmstorf critique

The critique finds two main problems with the article.

First. The fact that meteorite cluster can give information about the cosmic ray flux variability seems dubious. The original article draws some conclusions that don't seem to be reasonable, especially about the movement through the 4 galactic arms being so unperiodic.

Second. They use a very simple regression analysis which assumes variation on the scale of millions of years. The use of this on time scales of decades or centuries is a little questionable they contend (and I agree with).
Bystander
#5
Jun2-06, 11:08 PM
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Okay, learn sumpin' every day --- cosmic ray ionization of troposphere leads to increased cloud cover. From there we move to correlation of high CRF (cosmic ray flux) with reduced solar "constant" (less shielding), and the suggestion that the discrepancy between changes in solar "constant" and change in global mean temperature as derived from meteorological records ("gray body" effect of 2-4 watt increase over past century suggests 0.15 - 0.3 K increase compared to an unreviewed increase of 0.6 K in screen height air temperature measurements) can be explained, at least partly, by reduced cloud cover resulting from lower CRF due to increased solar activity.

That the way you read their "problem" statement, Norman? Don't wanta get too far gone critiquing their treatments or the critics' assessments 'til we're on the same page.


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