One of the great unsolved mysteries of science is the origin of life. How did it happen?

If we were able to click on Google Earth and visit the Earth during the Archean Eon, we would likely not recognize it is the same planet we inhabit today. The atmosphere was a reducing atmosphere of methane, ammonia, and other gases which would be toxic to most life. Also during this time, the Earth's crust cooled enough that rocks and continental plates began to form.

It was early in the Archean that life first appeared on Earth. Our oldest fossils date to roughly 3.5 billion years ago, and consist of bacteria microfossils. In fact, all life during the more than one billion years of the Archean was bacterial.

Through most of the 20th century, scientists thought that life began with a stupendous chemical fluke, unique in the observable universe.