Life on Mars: Difference between revisions

 

Mars is of particular interest for the study of the origins of life because of its similarity to the early Earth. This is especially so since Mars has a cold climate and lacks [[plate tectonics]] or [[continental drift]], so it has remained almost unchanged since the end of the [[Hesperian]] period. At least two thirds of Mars's surface is more than 3.5 billion years old, and Mars may thus hold the best record of the prebiotic conditions leading to [[abiogenesis]], even if life does not or has never existed there.<ref>{{cite journal |doi=10.1029/RG027i002p00189 |title=The early environment and its evolution on Mars: Implication for life |date=1989 |last=McKay |first=Christopher P. |last2=Stoker |first2=Carol R. |journal=Reviews of Geophysics |volume=27 |issue=2 |pages=189–214|bibcode = 1989RvGeo..27..189M }}</ref><ref name="Fromproto">{{cite journal |bibcode=2007prpl.conf..929G |arxiv=astro-ph/0602008 |title=From Protoplanets to Protolife: The Emergence and Maintenance of Life |last=Gaidos |first=Eric |last2=Selsis |first2=Franck |date=2007 |pages=929–44 |journal=Protostars and Planets V}}</ref> In May 2017, evidence of the [[Earliest known life forms|earliest known life]] [[Evolutionary history of life#Colonization of land|on land]] on Earth may have been found in 3.48-billion-year-old [[geyserite]] and other related mineral deposits (often found around [[hot spring]]s and [[geyser]]s) uncovered in the [[Pilbara Craton]] of [[Western Australia]].<ref name="PO-20170509">{{cite news|author=Staff |title=Oldest evidence of life on land found in 3.48-billion-year-old Australian rocks |url=https://phys.org/news/2017-05-oldest-evidence-life-billion-year-old-australian.html |date=May 9, 2017 |work=[[Phys.org]] |accessdate=May 13, 2017 |deadurl=no |archiveurl=https://web.archive.org/web/20170510013721/https://phys.org/news/2017-05-oldest-evidence-life-billion-year-old-australian.html |archivedate=May 10, 2017 }}</ref><ref name="NC-20170509">{{cite journal|last1=Djokic |first1=Tara |last2=Van Kranendonk |first2=Martin J. |last3=Campbell |first3=Kathleen A. |last4=Walter |first4=Malcolm R. |last5=Ward |first5=Colin R. |title=Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits |url=https://www.nature.com/articles/ncomms15263 |date=May 9, 2017 |journal=[[Nature Communications]] |doi=10.1038/ncomms15263 |accessdate=May 13, 2017 |volume=8 |page=15263 |deadurl=no |archiveurl=https://web.archive.org/web/20170518082609/https://www.nature.com/articles/ncomms15263 |archivedate=May 18, 2017 |bibcode = 2017NatCo...815263D }}</ref> These findings may be helpful in deciding where best to search for [[Abiogenesis|early signs of life]] on the planet Mars.<ref name="PO-20170509" /><ref name="NC-20170509" />

 

The search for Life on Mars past and present is the first of [[NASA]]’S four science goals<ref>Hamilton, V.E., Rafkin, S., Withers, P., Ruff, S., Yingst, R.A., Whitley, R., Center, J.S., Beaty, D.W., Diniega, S., Hays, L. and Zurek, R., [https://mepag.jpl.nasa.gov/reports/MEPAG%20Goals_Document_2015_v18_FINAL.pdf Mars Science Goals, Objectives, Investigations, and Priorities: 2015 Version]</ref>: