(July 30, 2015 at 4:03 am)Ashground Wrote: How could we prove it hadn't come from our 'tree of life'? Especially if there had been crossbreeding.
Well I was watching Thought The Wormhole, with Morgan Freeman, and there was speculation about microbes that really like Arsenic. This is normally poisonous to life and it lead into the question about life as we don't know it here on Earth. I can't remember which episode it was though.