View source for Why we need Mars to save humanity

A major reason why some of us what to colonize Mars is to save our species.    

== Extinction Level Events ==
At least 5 times in Earth’s history events have happened that destroyed almost all life.  Each time more than 75% of species disappeared from the Earth.<ref>https://www.discovermagazine.com/the-sciences/mass-extinctions</ref>  Scientists do not totally agree on the causes of all the mass extinctions, but the fact remains that they did happen.<ref>https://cosmosmagazine.com/palaeontology/big-five-extinctions</ref> <ref>https://en.wikipedia.org/wiki/Extinction_event</ref> <ref>Arens, N.C.; West, I.D. (2008). "Press-pulse: a general theory of mass extinction?". Paleobiology. 34 (4): 456–71. doi:10.1666/07034.1.</ref>  <ref>MacLeod, N (2001-01-06). "Extinction!"</ref>  It could happen again!   Past extinctions have been caused by asteroid impacts and maybe even by a supervolcano.<ref>Henehan, Michael J.; et al. (21 October 2019). "Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact". Proceedings of the National Academy of Sciences of the United States of America. 116 (45): 22500–22504. doi:10.1073/pnas.1905989116. PMC 6842625. PMID 31636204.</ref>  <ref>https://www.theguardian.com/science/2005/apr/14/research.science2</ref>  These circumstances can end human life.  The most predictable life-ending event will occur when the sun nears its end.  After billions of years, the sun will exhaust much of its hydrogen and become a red giant.  But, even before that, it will get brighter.  Long before reaching a red giant stage, the sun will cause our ice caps to melt and then the oceans to boil.<ref>https://www.universetoday.com/12648/will-earth-survive-when-the-sun-becomes-a-red-giant/</ref>  In the red giant phase the Earth may actually be orbiting inside the outer atmosphere of the sun. <ref>https://www.space.com/22471-red-giant-stars.html</ref> <ref>https://www.space.com/107-life-earth-escape-swelling-sun.html</ref>
Gamma ray bursts can destroy life.<ref>Corey S. Powell (2001-10-01). "20 Ways the World Could End". Discover Magazine.</ref>   Such bursts may have caused the Ordovician extinction.<ref>Melott, A.L.; Thomas, B.C. (2009). "Late Ordovician geographic patterns of extinction compared with simulations of astrophysical ionizing radiation damage". Paleobiology. 35 (3): 311–20. arXiv:0809.0899. doi:10.1666/0094-8373-35.3.311.</ref>   These are rare.<ref>Podsiadlowski, Ph.; et al. (2004). "The Rates of Hypernovae and Gamma-Ray Bursts: Implications for Their Progenitors". Astrophysical Journal Letters. 607 (1): L17. arXiv:astro-ph/0403399. Bibcode:2004ApJ...607L..17P. doi:10.1086/421347.</ref>   The burst has to be directed in our direction.  While they may affect several planets, Mars may not be affected if it were on the other side of the solar system.  
A scary scenario is being swallowed by a wandering black hole.<ref>https://www.theguardian.com/science/2005/apr/14/research.science2</ref>  Such things do exist, based on observations.<ref>https://www.space.com/43024-rare-black-hole-in-milky-way.html</ref> <ref>https://www.space.com/43024-rare-black-hole-in-milky-way.html</ref> <ref>https://phys.org/news/2020-01-astronomers-massive-black-holes-dwarf.html</ref>
There are also a huge number of rogue planets.<ref>https://www.scientificamerican.com/article/wandering-in-the-void-billions-of-rogue-planets-without-a-home/</ref>   They are not attached to a star. Instead they are just traveling in the darkness of space.  Scientists have estimated that there could be one Jupiter sized planet wandering around for every 4 stars.  They are created by gravitational interactions between stars.  Also, there may be as many rogue moons as stars.<ref>https://www.space.com/40016-rogue-exomoons-may-be-common.html</ref> <ref>Hong, Yu-Cian, et al.  2018.  Innocent Bystanders: Orbital Dynamics of Exomoons During Planet–Planet Scattering.  The American Astronomical Society. The Astrophysical Journal.  Volume 852.  Number 2</ref> <ref>https://iopscience.iop.org/article/10.3847/1538-4357/aaa0db</ref>    A strike by a body over 50 miles across would be a great disaster.  Estimates for the size of the asteroid that wripped out the dinosaurs range from 6 to a little over 50 miles across.<ref>https://en.wikipedia.org/wiki/Chicxulub_crater</ref> <ref>Durand-Manterola, H. J.; Cordero-Tercero, G. (2014). "Assessments of the energy, mass and size of the Chicxulub Impactor". arXiv:1403.6391 [astro-ph.EP].</ref> <ref>https://www.psi.edu/epo/ktimpact/ktimpact.html</ref>
An asteroid destroyed the dinosaurs and most life.<ref>Alvarez, Walter; Kauffman, Erle; Surlyk, Finn; Alvarez, Luis; Asaro, Frank; Michel, Helen (Mar 16, 1984). "Impact theory of mass extinctions and the invertebrate fossil record". Science. 223 (4641): 1135–41. Bibcode:1984Sci...223.1135A. doi:10.1126/science.223.4641.1135. JSTOR 1692570. PMID 17742919.</ref> <ref>Joel, Lucas (21 October 2019). "The Dinosaur-Killing Asteroid Acidified the Ocean in a Flash - The Chicxulub event was as damaging to life in the oceans as it was to creatures on land, a study shows". The New York Times. Retrieved 22 October 2019.</ref> <ref>Henehan, Michael J.; et al. (21 October 2019). "Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact". Proceedings of the National Academy of Sciences of the United States of America. 116 (45): 22500–22504. doi:10.1073/pnas.1905989116. PMC 6842625. PMID 31636204.</ref>  It could happen again, even though there are not as many asteroids left in our solar system.  Most have already collided with solar system bodies.  

We know of many possible events that could end human life on our planet.  There are probably others that we do not know about.  Despite listening for signals from other civilizations for decades, we have not found any.  One reason for this, perhaps, may be because intelligent species do not last long before some cosmic event occurs to take them out of existence. If we can establish colonies on Mars and learn how to live off the land, maybe the human race can survive and advance.

== Preservation of High Tech Culture ==
It is by no means certain that high technology cultures are stable in the long term (lasting hundreds or thousands of years).  If Earth was to lose high technology, it would be much harder for a high technology culture to appear because easy to exploit resources are used up.  However, people living on Mars, MUST preserve science and technology in order to maintain life-support.  If a disaster were to cripple Earth's technology, a high tech society could be re-seeded from Mars.

==References==
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==See  also==

*[[Air]]

*[[Glaciers on Mars]]
*[[How living on Mars will be different than living on Earth]]

*[[In-situ resource utilization]]
*[[Martian features that are signs of water ice]]

*[[Terraforming Mars]]

*[[Water]]