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From: Bobbie Sellers <blissInSanFrancisco@mouse-potato.com>
Newsgroups: rec.arts.sf.written
Subject: Re: "Washington Post Accidentally Admits Earth at Coolest Point in
 the Last 485 Million Years"
Date: Sun, 29 Sep 2024 19:46:25 -0700
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On 9/29/24 13:45, William Hyde wrote:
> James Nicoll wrote:
>> In article <vd9rlv$1dcog$1@dont-email.me>,
>> William Hyde  <wthyde1953@gmail.com> wrote:
>>> of direct observation does not agree with this view.
>>>
>>> As to the current warming the question is academic, as the pattern of
>>> warming shows us clearly that this is not due to  an increase in solar
>>> output.
>>
>> Is this a good time to mention the faint young Sun paradox?
>>
>> For people unfamiliar with it, is the question of how to
>> reconcile the young sun being 30% dimmer with the young Earth
>> having liquid water. All things being equal, the Earth should
>> have been well below freezing (on average) but it wasn't. So
>> all things weren't equal.
> 
> 
> Always a fascinating topic for me.
> 
> This is not resolved, but the most common idea is that the thick 
> atmosphere of the young earth, filled with CO2, H20 and possibly other 
> infrared absorbers (NH3, for example) kept the earth warm. But there is 
> no consensus on the composition of that atmosphere.  Perhaps there 
> wasn't much in the way of greenhouse gases.
> 
> Long ago Dirac came up with an idea, not often mentioned, that certain 
> fundamental constants of the universe change over time, while 
> maintaining constant ratios with one another.
> 
> One of these constants was G, which according to this idea should 
> decrease over time.  Petr Chylek mentioned this idea to me, and I was 
> intrigued because solar output varies as G**7 according to a monograph 
> by A. D. Vernekar.
> 
> Using a simple climate model I was able to put an upper limit on the 
> Dirac change by considering the early earth.    If the greenhouse effect 
> of that atmosphere was zero, a given increase in G would account for 
> early climates, a larger one would make the earth too warm.
> 
> I went through a bit of a career change at the time and the work, though 
> presented at a number of seminars, was never submitted for publication. 
> As there is (or was at the  time) little interest in Dirac's idea it 
> would have been difficult to get it in print anyway and more recent ice 
> ages beckoned.
> 
> While looking for some online reference to Dirac's idea I was reminded 
> yet again of how much Dirac actually did.  Even if he had never come up 
> with the Dirac equation and predicted antimatter, he'd still have been 
> one of the great scientists of the 20th century.
> 
> 
> William Hyde
	
	First we should not call it the Young Earth because that
is a creationist theory. I learned that when I searched on the
term.

	Excuse me but did not the Early Earth contribute to it own
heating? One of the reasons that the air was full of water vapor is
that the temperature was higher than the boiling point of water.
	The Early Earth was still suffering tremendous imparts as
its orbit intersected those of other massive pieces of the previous
calamitous end of a star that was not too far from Sol.
	But as soon as it cooled we got a Snowball Earth. Then
the impact of large planetary sized object which knocked the
Moon out of the earth and into orbit. So the stage was set for
the disasters and extinctions to follow which gave rise eventually
to us, Homo Sapiens aka the Wise Guy. Following further along
the time track to science and technology we end up with us making
the Earth, our rocky cradle too messed up to keep us alive.
Wise guy was a misnomer apparently.

	<https://en.wikipedia.org/wiki/Early_Earth>

	bliss

-- 
b l i s s - S F 4 e v e r at D S L E x t r e m e dot com