As the geological evidence of Earth proves, life comes and goes on this planet in a blink of an eye. It has been estimated that there have been between five to twenty mass extinction events on Earth since life first appeared. Each caused by different events, such as Flood basalt events, Sea-level falls, Impact Events, both Global Cooling and Global Warming and other lesser known events. Now, for the first time in recorded history, a species that evolved on Earth has the ability to leave it if it so chooses to possibly avoid such events. So why should we leave Earth and attempt to colonize another planet? For humanity to survive, either from its own doings or natural events, we need to spread out across the stars.
The Earth is an ever changing place, no matter what causes that change. Tectonic plates shift, polar-shifts are predicted to occur, volcanic activity and sea levels are constantly changing and natural diseases continuously pop up from time to time. Not to mention the millions of large chunks of rock, ice or iron that comes close to our planet on a seemingly daily basis. For humans not to adapt with everything we face as a species would be disastrous.
Humans have always had a desire to seek out new places, to spread out past the known into the unknown. When we become stagnant we risk cultural collapse as well as inviting diseases to come in a wipe us out, such as what happened with the several Black Plagues that have dotted history. But more importantly, the unpredictable cosmos that surrounds us is the most effective argument to continue to seek out the unknown in space.
Even now we find ourselves only noticing near earth asteroids after they have passed or within a few weeks of passing our planet. Just recently a near-Earth asteroid, 2010 AL30, was discovered just three days before it passed by Earth at a mere 76,000 miles which is about 1/3 of the distance from the Earth to the Moon. Granted this particular asteroid was not large enough to cause mass extinction, but it was large enough to cause a dangerous airburst of between 50 to 100 kilotons of TNT force or three times the force created by the atom bomb dropped on Hiroshima.
If humanity, given the fact that we are the first to have the ability to do so on this planet, could spread out across the solar system, the risk of full extinction by such an event would be greatly decreased. If there is a sizeable colony on Mars and something catastrophic happens to Earth, then humanity has a real chance of continuing on. We are a young race, with the God-given ability to adapt and learn, and to realize how to survive the ever changing cosmos. Let us do so before it is too late.
Resources:
Extinction Level Events. BBC. 23, November 1999. Web. Retrieved from http://www.bbc.co.uk/dna/h2g2/ A207415.
National Aeronautics Space Administration. Near Earth Object Program, Last Modified 06 Feb. 2011. Retrieved from http://www.dailymail.co.uk/sciencetech/article-1301482/Human -race-colonise-space-face-extinction-warns-Stephen-Hawking.html.
Main Online. Human race ‘must colonise [sic] space or face extinction’, warns Stephen Hawking, 10 Aug. 2010. Retrieved from http://www.dailymail.co.uk/sciencetech/article-1301482/Human -race-colonise-space-face-extinction-warns-Stephen-Hawking.html.
