http://www.msnbc.msn.com/id/46632008/ns/technology_and_science-science/t/mystery-still-why-early-earth-didnt-freeze-over/
<<For greenhouse gases to explain the faint young sun paradox, their concentrations would need to have been extremely high, hundreds to thousands of times as much as today. "If levels of carbon dioxide were that high, they would be recorded in ancient soils and sediments in the rock record," Pope said. "If levels of methane were that high, they would actually form a kind of organic haze in the atmosphere that blocks the sun's rays and would counteract its properties as a greenhouse gas." Now scientists analyzing relatively pristine 3.8-billion-year-old rocks from Isua find no evidence that greenhouse gas levels were high enough to explain the faint young sun paradox, further deepening the mystery, Pope told LiveScience. >> harry On Tue, Aug 14, 2012 at 8:05 PM, Robert Lynn <[email protected]> wrote: > Probably the most sensible solution is that the atmosphere was significantly > thicker. 30% less heat input would drop the earth's temperature by about > 20°C, but 20% more mass of air would increase the temperature by about 20°C > at ground level. We know that during the age of the dinosaurs that there > was a lot more oxygen in the atmosphere, it was up to about 30% O2 vs 20% > now. Assuming the quantity of nitrogen is about the same (pretty safe as it > doesn't react significantly or leak away) then you are looking at another > 10°C just in the extra thickness of atmosphere caused by that extra oxygen. > > > Before about 800 million years ago the atmosphere had very little O2 and a > whole lot of CO2, which would have made the atmosphere even thicker and > further increased the temperature at the surface. > > > > Also the earth was spinning a lot faster and the thicker atmosphere > transported heat better from the tropics to the poles, producing a wider > latitudinal band of temperature climates (this is known from geological > studies) > > > On 14 August 2012 23:27, Harry Veeder <[email protected]> wrote: >> >> Models of the Sun's evolution predict the Sun was 70% percent as >> bright 2 billion years ago, and the Earth should have been an ice ball >> at that time. Yet the geological record indicates the oceans were >> liquid. >> >> A number of explanations have been proposed which haven't faired well >> upon closer study. The lastest explanation says that the Earth at one >> time orbited closer to the Sun: >> >> http://www.sciencedaily.com/releases/2012/05/120530152034.htm >> >> >> Here is another: If LENR occurs inside the Earth then perhaps there >> was sufficient LENR activity in the Earth billions of years ago to >> keep the oceans liquid. >> >> >> harry >> >
