# Fermi Paradox **URL:** \ **Category:** Great Debates\ **Created:** [September 1, 2014, 3:06am UTC](https://boards.straightdope.com/t/fermi-paradox/697104 "2014-09-01T03:06:13Z")\ **Posts on this page:** 8\ **Page:** 4
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [September 13, 2014, 9:15am UTC](https://boards.straightdope.com/t/fermi-paradox/697104/61 "2014-09-13T09:15:12Z")
> [@chorpler](#): > > (removed garbage characters posted accidentally from Tapatalk on my phone) One possible explanation for the WOW! signal here, I think. ---
**Author:** ![Bozuit](https://avatars.discourse-cdn.com/v4/letter/b/edb3f5/32.png) [@Bozuit](https://boards.straightdope.com/u/Bozuit)\ **Post date:** [September 13, 2014, 3:23pm UTC](https://boards.straightdope.com/t/fermi-paradox/697104/62 "2014-09-13T15:23:15Z")
> [@wolfpup](#): > > Perhaps the very concept of “colonization” is… well, colonial. Planets in other star systems might either be outside the habitable zone or else inhabited – one or the other – a fact that might be known to advanced civilizations who might have a different view of colonization than more primitive societies. Maybe, in order to survive long enough to be able to colonize other planetary systems, it’s necessary for a species to leave behind expansionist ideas and overpopulation, and such a species wouldn’t consider colonization of other places an end in itself, rather than a means to one. It may be that they could colonize but, without the need to do so, there’s no desire. It’s difficult to imagine a species with millions of years of history, though, our own being so comparatively short. ---
**Author:** ![Section\_Maker\_Jupe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/section_maker_jupe/32/1424_2.png) [@Section\_Maker\_Jupe](https://boards.straightdope.com/u/Section_Maker_Jupe)\ **Post date:** [September 13, 2014, 4:37pm UTC](https://boards.straightdope.com/t/fermi-paradox/697104/63 "2014-09-13T16:37:16Z")
Perhaps, when the universe starts to contract, and the distances are a bit smaller, there could be a kind of Family reunion, before everything gets put into that one small point…again:D ps dont want to hijack but that whole Big Bang thing, makes me 😕 confused!! ---
**Author:** ![Bozuit](https://avatars.discourse-cdn.com/v4/letter/b/edb3f5/32.png) [@Bozuit](https://boards.straightdope.com/u/Bozuit)\ **Post date:** [September 13, 2014, 6:52pm UTC](https://boards.straightdope.com/t/fermi-paradox/697104/64 "2014-09-13T18:52:24Z")
It’s generally thought that the universe will continue to expand forever. Eventually everything will be so far apart that, even if someone were still alive, they would look into the night sky and see no stars. That also means that all the energy will eventually be so dispersed that everything will become a uniform temperature and nothing of much interest can happen - certainly not life. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [September 14, 2014, 5:55am UTC](https://boards.straightdope.com/t/fermi-paradox/697104/65 "2014-09-14T05:55:43Z")
Yeah, but we’ve got trillions of years before that happens, and during that time all the countless invisble red dwarfs in the sky will be getting brighter and brighter until the Galaxy is full of Sun-bright stars. The Galaxy will be a very habitable place a trillion years from now, more than it is today. After that- well some people have been making plans to live in the deep future - check out Freeman Dyson’s essay Time Without End - Physics and Biology in an Open Universe [http://www.aleph.se/Trans/Global/Omega/dyson.txt](http://www.aleph.se/Trans/Global/Omega/dyson.txt) ---
**Author:** ![Bozuit](https://avatars.discourse-cdn.com/v4/letter/b/edb3f5/32.png) [@Bozuit](https://boards.straightdope.com/u/Bozuit)\ **Post date:** [September 14, 2014, 8:44am UTC](https://boards.straightdope.com/t/fermi-paradox/697104/66 "2014-09-14T08:44:29Z")
My post was just a response to **Section Maker:Jupe’s** “Big Crunch” speculation. I’ll certainly read that when I get a chance, though. ---
**Author:** ![Section\_Maker\_Jupe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/section_maker_jupe/32/1424_2.png) [@Section\_Maker\_Jupe](https://boards.straightdope.com/u/Section_Maker_Jupe)\ **Post date:** [September 14, 2014, 7:50pm UTC](https://boards.straightdope.com/t/fermi-paradox/697104/67 "2014-09-14T19:50:51Z")
ugg the Big Freeze instead! Some serious down time coming with that, or no time! Jeez, depressing, time to swim in the ocean 😃 ---
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [September 14, 2014, 8:35pm UTC](https://boards.straightdope.com/t/fermi-paradox/697104/68 "2014-09-14T20:35:49Z")
> [@Mijin](#): > > Actually it is normally the other way round: that so-called “simple” cells are actually pretty complex, and so this is usually the part that some people describe as so unlikely that we may be alone. The truth on that is, we don’t quite know yet. We already know that cells were not just spontaneously formed (e.g. how RNA likely became DNA, how mitochondria was captured etc), but there are still a lot of gaps. How likely cells are to form on an Earthlike world is still something we can speculate freely about. > > But, once you have such cells, and a mechanism for passing on genetic variation, that’s all you need for a ratchet effect of increasing variation and specialization. It’s difficult for us to imagine complex animals coming about this way, but that’s just a failure of our imagination, because that’s exactly what happened, and it took mere millions of years, in a universe that’s been about for billions. I went over to wikipedia and put the evolution of life on a timeline to get a sense of where the bottlenecks were. ```auto Billion years ago 4.5 Earth formed 4.4 4.3 4.2 4.1 4 3.9 3.8 3.7 Earliest Evidence for microbial life 3.6 3.5 Oxygenic Photosynthesis -------- 3.4 | 3.3 | 3.2 | 3.1 | 3 | 2.9 | 2.8 | 2.7 | 2.6 | 2.5 | 2.4 Oxygenation of atmosphere -------- 2.3 2.2 2.1 2 1.9 1.8 Eukaryotes: Still single celled, but with orgenelles 1.7 Multi-cellular organisms 1.6 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 Bilateral organisms 0.5 Land plants, Cambrian explosion 0.4 0.3 0.2 Dinosaurs 0.1 0 Humans ``` A: Hard to say in many ways. It’s possible that life arose quickly, but evidence for it would be dodgy in early Earth days. But at any rate it took 1.2 billion for evidence of life to appear and another 1.9 billion for Eukaryote evidence to arise. Eukaryotes may have arisen earlier though. Still there’s some evidence that the bottleneck is creating microcellular organisms with their own organelles. Interestingly, multicellular life occurs a mere 150 million years later. I takes another 1.1 billion years for billateral organisms to arise. Then the Cambrian explosion occurs and the pace really picks up. So: bottleneck candidates: Creation of microscopic life: Not clear. Creation of Eukaryotes from earlier forms of microscopic life: I’m guessing this is a big bottleneck, but that’s a WAG. Creation of multicellular life from Eukaryotes: pshaw. That’s relatively easy. Unless Eukaryotes actually appeared much earlier. Creation of complicated animals with bilateral symmetry from multicellular life: Actually this took a while. 1.1 billion years. Everything else: pshaw. Lots of animals use tools. Lots of social mammals have an arms race prompting increasing cognitive abilities. (canines, dolphins, primates). Put the two together and you get intelligence. Asteroid impacts can set the process back of course. [Previous page](https://boards.straightdope.com/t/fermi-paradox/697104.md?page=3)