Ancient Rocks Show How Young Earth Avoided Becoming Giant Snowball

Science Daily ^ | 2-5-2007 | University Of Chicago

[Sam Ketcham]

Thanks

[Tarpon]

Earth may have avoided becoming frozen solid early in its history, when astrophysicists believe the sun was 25 percent fainter than today.

Warm is a good thing.

Since most living things exhale CO2, what are we going to do about that? When did CO2 become the deadly gas that was going to kill us all?

[StopGlobalWhining]

Bump

[Gondring]

ping

[NicknamedBob]

"...chemical weathering decreases, carbon dioxide accumulates in the atmosphere, ..."

How does a decrease in weathering lead to an increase in CO2?

As near as I can piece it together, chemical weathering in this instance is primarily the action of carbon dioxide dissolved in rainwater, making carbonic acid. With lower temperatures and much water locked up as ice, there would be less rainfall.

Less rain to dissolve the carbon dioxide out of the atmosphere, thus letting it accumulate.

It may be that CO₂ levels act as a control only at the lower temperature levels, while H₂O functions as the high-temperature safety valve. -- CO₂ accumulation keeps the world from staying frozen, and the boiling convention action and reflection characteristics of water vapor accumulation keeps it from getting too hot.

[Freedom4US]

hey i think that's my rock, from my collection.

[AndrewC]

The iron probably was released with other metals in hydrothermal vents called black smokers found along mid-ocean ridges

[ChessExpert]

Thanks for the answer to my question! I expect I will return to it from time to time.

I like the idea of a control to keep temperatures from going too low, and a control to keep temperatures from going too high. It is almost like it was designed that way.

[Lancey Howard]

Thank goodness for "global warming".

[NicknamedBob]

Add the challenges of slowly migrating continents, punctuated equilibrium, the presence of an inordinately large moon beckoning us to extend our grasp, and all the other curious coincidences that not only permit but practically drive us in a particular direction, and it's hard to believe it all happens just by chance, isn't it?

Einstein was reputed to have said, "God does not play dice with the Universe."

I'm inclined to agree. But I also think God might like an occasional game of billiards, or perhaps just tinkering around with the way dominoes fall.

[SunkenCiv]

http://www.freerepublic.com/focus/news/1805973/posts?page=17#17

[SunkenCiv]

Note: this topic is from February 5, 2007.

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[SunkenCiv]

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