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Strange-Ad1209 t1_ixjqi8i wrote

Reply to comment by s1ngular1ty2 in what would happen if a liquid mass of water collided with earth? by Brave-Line-6326

And all of the impacts that brought water were while the Earth was molten rock anyway. Except for the late term bombardment which heavily cratered the Moon and of course the Earth equally so, most impacts occurred in the first Billion years of Earth's 4 Billion year existence. Life didn't even appear until 2 Billion years ago and that was single cell stuff. Great Permian Mass extinction was 240 Million years ago. Dinosaurs 65 Million years ago. Many Mega Fauna 50,000 years ago from a string of Asteroid strikes like one here in Arizona near Winslow. Then the Usselo Horizon 26,000 years ago largely world wide forest fires from meteor strikes leaving layers of charcoal world wide. Asteroid winters usually only last about 1000 to 2000 years before clearing.

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s1ngular1ty2 t1_ixjqpn0 wrote

Incorrect. Stop trying to tell me things you don't even understand. Life existed almost immediately after the Earth formed. New evidence puts primordial life back to almost the very beginning of the Earth's existence. You should do some more research on the topic.

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live_2_know t1_ixl8qdg wrote

Agreed. Single cell life evolved around 4-3.5 billion years ago when the early earth's atmosphere was devoid of appreciable levels of oxygen. Many of these early life forms died out in the first mass extinction brought on by the evolution of cyanobacteria and the subsequent great oxygenation event of our planet about 2.5 billion years ago. It is always fascinating to remember that the introduction of such a reactive element (oxygen) to our planet in the form of O2 resulted in evolutionary opportunities for energy capture in biological systems by oxidation of food (sugars, amino acids, fats) to generate ATP and GTP. Processes that we humans carry out with respiration. Increased available oxygen dissolved in world oceans and in the atmosphere also lead to an extensive diversification in the minerals present on earth. So the rise of oxygen producing life forms actually terraformed earth to the conditions we see as 'normal' today. We live by exploiting oxidation in a world crafted by oxygen generating life. You can still see cyanobacterial stromatolites in Shark Bay, Australia and imagine a similar scene 2 billion years ago.

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