During the Archean Eon, the Earth was very different from how it is today. In fact, the Archean atmosphere is thought to be devoid of oxygen! It was also a moderately warm and very wet climate; near constant volcanic eruptions due to increased tectonic activity caused ceaseless rain and violent lightning, and large amounts of greenhouse gases trapped heat in the atmosphere. This kept the climate at near-modern levels, despite the fact that the sun was about 30% dimmer than it is today.
Fun Fact: The Faint Young Sun paradox demonstrates the contradiction between liquid water in the Archean eon and the expectation that the sun would only be about 70% as intense as it is today. It was pointed out in 1972 by two scientists, Carl Sagan and George Mullen, and has been explained by greenhouse effects and/or astrophysical influences.
There is ample evidence for liquid water in the Archean Eon, which is thought to have existed as early as a few hundred million years after Earth's formation. Oceans were probably created by water condensation, a byproduct of volcanic eruption. At the beginning of the Archean, the Earth was entirely covered in water. Oceanic basins were known to have existed during the Archean, and the presence of liquid water can be shown by deformed gneisses produced by morphing of protoliths.
By the end of the Archean, the Earth was a lot more similar to what it is like today: it had modern continent structure and pate tectonics, there was much more oxygen in the air, and the oceans were less green than they were about a billion years before.
The earth was completely covered in acidic ocean at the beginning of the Archean however, land masses did appear later. Although the sun was dimmer, the climate was warm because the greenhouse gases retained heat and the core was much hotter than it is now. It rained constantly and there was violent lightening.
ReplyDeleteAt the beginning of the Archean, the atmosphere was devoid of oxygen, wet, gassy and warm. Though the sun was dimmer, greenhouse gasses, volcanic eruptions and increased tectonic activity kept the earth at near-modern levels. The earth was entirely covered in water. As time progressed, it became much more like the Earth as we know it today.
ReplyDeleteIn the beginning of the Archean the earth was covered in ocean that was acidic and warm, without any oxygen in the atmosphere, it was also wet from the ocean and the volcanic eruptions that spewed water vapor into the air. Even though the sun was thirty percent dimmer, the tectonic activity, volcanic eruptions, and greenhouse gasses all brought the temperature to what it is today. It rained a lot fom the eruptions, as well as it had lightning.
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