Reposting because somehow the first url ended up as a Google link rather than to the Cambridge site.<p>I think about this paper a bunch because it really challenges some assumptions we have about time and how long things stick around. It's pretty interesting to think that, had there been some advanced technological society in ancient times, there wouldn't actually be much evidence. Hard to believe, but the authors walk through the logic of their thinking in the paper.<p>People sometimes get a little huffy about this paper because they think it's trying to advance some kind of 'ancient aliens on earth' narrative. But, it's not saying there WAS an ancient civilization. Just showing how hard it would be to actually show that one did exist.<p>I also think about this a lot in the context of Venus, with its runaway greenhouse effect. A mystery in our own cosmic backyard.
Big recent thread <a href="https://news.ycombinator.com/item?id=42106700">https://news.ycombinator.com/item?id=42106700</a> among several over the years <a href="https://hn.algolia.com/?q=silurian+hypothesis" rel="nofollow">https://hn.algolia.com/?q=silurian+hypothesis</a>