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Comment by havemylife | Hacker News Reader

I'm not discounting the possibility of life on Earth originating from somewhere other than Earth. However, why would the early conditions of Earth not be sufficient for life to begin over say any other object in space with the base elements for life?

How life began is obviously still an unanswered question, but if the conditions for self replicating molecules were sufficient early on for Earth, I'm not sure why billions of years would be needed for life to form versus several hundred million years.

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Earth needed ~ 2 billion years for life to start. Frequent solar winds - especially in the first few billion turbulent years of the universe - basically sterilize planets and the whole 2-billion-year counter gets reset to 0.

Planets that exist without a solar system, but do retain sufficient heat, might have been out of solar winds harm ?

Life on Earth started within a few hundred million years, not 2 billion years.

I'm by no means well informed on these topics, but I'm unsure where you're getting your 2 billion year estimate. Furthermore I thought that Earths magnetic field shielded from solar radiation, and additionally that there's a significant amount of radiation in space anyways.

Further questioning I have though is, does solar radiation penetrate through ocean water?

What radiation is between solar systems or what rogue planets would likely encounter, and how that effects single cell life, amino acids, organic compounds, and any other building blocks to life?

>>Further questioning I have though is, does solar radiation penetrate through ocean water?

Barely. 10km of water will shield you from almost any amount of radiation, and we know of life forms which live at those depths, so they could have developed even when Earth was completely bathed in radiation.

Life appears to have started on Earth remarkably soon after the creation of the planet and the subsequent formation of oceans - ~130 million years by some estimates:

https://en.wikipedia.org/wiki/Abiogenesis#Earliest_biologica...

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