Editing Rare Earth hypothesis (section)

==Fermi paradox==
{{Main|Fermi paradox}}
There is no reliable or reproducible evidence that [[Extraterrestrial life|extraterrestrial organisms]] of any kind have visited [[Earth]].<ref name="ConversationNoUFOs">{{cite news |last1=Tingay |first1=Steven |title=Is there evidence aliens have visited Earth? Here's what's come out of US congress hearings on 'unidentified aerial phenomena' |url=https://theconversation.com/is-there-evidence-aliens-have-visited-earth-heres-whats-come-out-of-us-congress-hearings-on-unidentified-aerial-phenomena-183443 |access-date=27 October 2022 |work=The Conversation |language=en}}</ref><ref name="NewYorkerAliens2021">{{cite magazine |last1=Kolbert |first1=Elizabeth |title=Have We Already Been Visited by Aliens? |url=https://www.newyorker.com/magazine/2021/01/25/have-we-already-been-visited-by-aliens |access-date=27 October 2022 |magazine=The New Yorker |date=14 January 2021}}</ref> No transmissions or evidence of [[intelligent]] life have [[SETI|been detected or observed]] anywhere other than [[Earth]] in the [[Universe]]. This runs counter to the knowledge that the Universe is filled with a very large number of planets, some of which likely hold the conditions hospitable for life. Life typically expands until it fills all available niches.<ref name="AreWeAlone">{{Cite journal|url=https://adsabs.harvard.edu/full/1978QJRAS..19..277P|title=1978QJRAS..19..277P Page 277|journal=Quarterly Journal of the Royal Astronomical Society|bibcode=1978QJRAS..19..277P |last1=Papagiannis |first1=Michael D. |year=1978 |volume=19 |page=277 }}</ref> These contradictory facts form the basis for the Fermi paradox, of which the Rare Earth hypothesis is one proposed solution.