Have you ever washed your hands with alcohol scrub, boiled water,
sprayed something with lysol and thought "Ha! no more microorganisms
there." Well we know today that no matter how much alcohol, lysol,
and boiling water we apply to a surface, there will always be a
microorganisms that survives. Always.
We call these microorganisms life. Let's take a moment to reexamine
the word life as defined by Webster's Dictionary
"Life"
http://www.merriam-webster.com/netdict/life
Now let's look at how astrobiologists
http://en.wikipedia.org/wiki/Astrobiology
are redefining our definition of "life".
Astrobiologists are anticipating the discovery of terrestrial planets (small rocky planets, ex. Earth) by the Kepler Mission. Once Kepler discovers terrestrial planets inside the Goldilocks zone it will be time for the astrobiologists to take all their research and begin programming it into government or private research detectors.
In the meantime Kepler is busy determining how many terrestrial planets exist outside our solar system while astrobiologists are busy taking samples from deep undersea volcanic vents where lava spews into the deep ocean. Why would a biologist waste their time looking for life in such an inhospitable place?
Much like your memories of turning over your first rock as a child to find a plethora of living organisms, where you reasoned there could be none due to being smashed flat, astrobiologists are looking for microbiological life in and on places across the face of the planet under other proverbial "rocks". They bring the same open minded curiosity you had as a child, though as well educated researchers to the field of astrobiology.
These "rocks" they turn over include; the outside of the space shuttle, nuclear waste sites, glacial ice cores, the inside of active volcanoes, at the top of the Himalayan Mountains, the deep abyss of caverns, and in the great deserts such as the Gobi and the Sahara. All places where we as multi cellular, multi-system based intelligent life would either perish instantly or not sustain long without life support systems.
The samples from these forsaken places have returned the evidence of extremophiles
http://www.newscientist.com/article/dn12433-eightmillionyearold-bug-is-alive-and-growing.html
with subsets such as thermophiles. Thermo.....what? Thermophiles, these are heat loving "living" organisms. These are the microorganisms that would not die at the bottom of you pot of boiling water.
Cryophiles are the microorganisms that after being "frozen" in glacial ice cores for thousands of years when melted decide to reanimate themselves as if they had been hanging out on a beach in Hawaii.
Let's talk about the habitable zone, or as we have labeled it, the Goldilocks zone. Many scientists agree that the Goldilocks zone in ours and other solar systems is a narrowly defined corridor that is not too far from the sun but not to close. Think frozen lake or baking desert. Earth is a simplistic way to look at what is just right, at least for highly developed intelligent life. Therein lies the way we define the habitable zone. We generally are defining for highly developed intelligent life such as humans, thereby excluding the majority of life on the planet Earth, from measurements of how large the habitable zone could be...
If we find simple microorganisms inside boiling hot thermal vents at the bottom of pitch black oceanic trenches, why would it be hard to say that we couldn't find it inside one of Io's active volcanoes.
Io
http://en.wikipedia.org/wiki/Io_(moon)
The Goldilocks zone has been narrowly defined by the orbit of Earth, not to close, not too far from our sun. Though as we can see if we open our mind and searches to microbiological life we can and should expand the Goldilocks zone to, dare we say, the entire Universe (Tyson, 2006). We need to rediscover the childhood surprise we had when we first turned over that rock and found minute biological life abound. Thereby opening our minds from childhood forward to the fact that under even the largest and heaviest boulders there is life. So to in the Universe even under the most extreme conditions we will be surprised by what might be thriving out in the vastness of the cosmos.
References:
Gay, Pamela L., and Fraser Cain. "Astrobiology." Audio blog post. AstronomyCast. 21 June 2009. Web. 05 Feb. 2010.
.
Tyson, Neil. Death by Black Hole. New York: W.W. Norton and Company, 2006. Print.