Theories on why we haven't found alien life yet.

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Graphitetshirt on December 8th, 2018 at 06:38 UTC »

I really like the Early Birds theory, that was new for me

Jaybobi on December 8th, 2018 at 06:59 UTC »

The great filter is a really interesting idea, but I don't think it's well represented in that graphic.

The concept is basically that between very simple life originating and becoming a type III civilisation, there's an inevitable barrier that gets in the way.

This might be some external planetary disaster as in the graphic, but there's a huge amount of other theories as to when the great filter might be - for example, the ability for cells to replicate, the transition to multi celled organisms; there's a lot of complex stages that occur way before humanity that could well be unlikely enough to be the great filter.

But one interesting idea is that the great filter hasn't happened yet for life on earth - in other words, something inevitably happens between current levels of civilisation and galaxy crossing levels of civilisation. Nuclear war? Resource depletion?

The great filter is the idea that there's something inevitable that stops life in it's tracks before becoming a type III civilation wherever in the universe it arises. What that might be is mostly speculative of course, but also cool and scary to think about

jtchris_g on December 8th, 2018 at 08:33 UTC »

Is there a subreddit for this kind of topic? I find all this super interesting