How was the early earth different from the earth we know today?

1 Answer
Sep 17, 2015

This is unanswerable until you determine what you mean by "early" Earth. For the three billion years or so the Earth was scalding hot (molten for the most part). It was completely uninhabitable even before the hypothetical catastrophic impact that completely melted the crust of the planet and put enough material into space to create the moon.

After the Earth solidified the atmosphere was still poisonous.

After that there were periods of ice ages which resulted in layers of ice over 50 miles thick.

This was all before anything more complicated than bacteria even evolved.