Exploring the Validity of Veizer and Shaviv's GCR Theory

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In summary, the paper by Veizer and Shaviv looks at geological records and compares them to some models of the GCR spectrum. It is not considered mainstream science at this point, with some critics saying that the conclusions don't seem reasonable.
  • #1
Norman
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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 http://www.gsajournals.org/gsaonline/?request=get-abstract&doi=10.1130%2F1052-5173(2003)013%3C0004:CDOPC%3E2.0.CO%3B2[".
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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"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.
 
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  • #3
Sorry didn't realize 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 http://www.envirotruth.org/docs/Veizer-Shaviv.pdf" [Broken]
 
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  • #4
Here is a good critique of the previous paper.
http://www.soest.hawaii.edu/GG/FACULTY/POPP/Rahmstorf%20et%20al.%202004%20EOS.pdf" [Broken]

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).
 
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  • #5
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.
 

1. What is Veizer and Shaviv's GCR theory?

Veizer and Shaviv's GCR (galactic cosmic ray) theory proposes that changes in the Earth's climate are primarily driven by fluctuations in the intensity of galactic cosmic rays, rather than by human activities such as greenhouse gas emissions.

2. How is the validity of Veizer and Shaviv's GCR theory explored?

The validity of Veizer and Shaviv's GCR theory is explored through various scientific studies and research, including analyzing geological and climate data, conducting experiments, and building computer models.

3. What evidence supports Veizer and Shaviv's GCR theory?

Some evidence that supports Veizer and Shaviv's GCR theory includes correlations between cosmic ray flux and global temperatures, as well as geological records that show periods of increased cosmic ray activity coinciding with cooler climate periods.

4. What are some criticisms of Veizer and Shaviv's GCR theory?

Some criticisms of Veizer and Shaviv's GCR theory include the lack of a clear mechanism for how cosmic rays could affect Earth's climate, the limited time frame of the theory's applicability, and the potential oversimplification of complex climate processes.

5. What is the current consensus on the validity of Veizer and Shaviv's GCR theory?

The current consensus among the scientific community is that Veizer and Shaviv's GCR theory is not a significant driver of changes in Earth's climate. While there may be some correlation between cosmic ray activity and climate, it is likely not the main cause, and other factors such as greenhouse gas emissions have a much larger impact on climate change.

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