Wednesday, September 10, 2008

Early earth should have been a frozen wasteland

From the geologic record, we believe liquid water has been around for 3.7 billion years. Yet from observations of other stars in the universe, we believe that, 3.7 billion years ago, our sun would have been too dim to keep temperatures at the Earth's surface above freezing. This is known among scientists as the "faint young sun problem."

According to
a report at Space.com, most theories explaining the "problem" have revolved around greenhouse gases. Basically, theories suggest the early earth was so high in CO2, for example, that a greenhouse effect kept temperatures high enough for liquid water. The problem with that, according to some research teams, is that geologic evidence shows CO2 levels were "far too low to keep the surface from freezing."

But one of the same teams that disputed the CO2 theory is shifting its position. In a new calculation that factors in important periods and milestones in Earth's history (for example, a phase of regular asteroid impacts called the Late Heavy Bombardment, the appearance of bacteria and the first known oxidation) a German team led by Philip von Paris of the Institute for Planetary Research (in Germany) believes those "low" levels of CO2 were enough to keep the planet's surface above freezing.

The Space.com doesn't get into specifics on how the Late Heavy Bombardment, bacteria and oxidation affect the climate model.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.