reply to post by elevenaugust
Okay, where to begin?
With this paper, I want to demonstrate that we are probably living in the most important century for the humankind, as (and this is not only a strong intuition) there's no doubt in my mind that the final proof of extraterrestrial life will be found within the century.
- Distance is still an obstacle: discoveries methods can only be used in a combination way for relatively nearby stars out to about 160 light-years from Earth (exceptionnally up to 300 light-years):
as of February 2011, NASA's Kepler mission had identified 1,235 unconfirmed planetary candidates associated with 997 host stars, based on the first four months of data from the space-based telescope, including 54 that may be in the habitable zone.
Originally posted by elevenaugust
Okay, where to begin?
the final proof of extraterrestrial life will be found within the century.
I think we shouldn't limit ourselves by just searching for "Earth sized" planets in habitable zones. Other larger and smaller planets in the same zone may also contain life. If we are just looking for another planet to colonize then yes we need similar atmosphere and gravity etc which an Earth sized planet may offer. But, If we are searching strictly for signs of "Life" it may have found a way to develop on any number of sized planets in the "Habitable Zone. IMO.
There are many different classes of extremophiles that range all around the globe, each corresponding to the way its environmental niche differs from mesophilic conditions. These classifications are not exclusive. Many extremophiles fall under multiple categories. For example, organisms living inside hot rocks deep under Earth's surface are both thermophilic and barophilic.
An organism with optimal growth at pH levels of 3 or below
An organism with optimal growth at pH levels of 9 or above
An organism that lives in microscopic spaces within rocks, such as pores between aggregate grains; these may also be called Endolith, a term that also includes organisms populating fissures, aquifers, and faults filled with groundwater in the deep subsurface.
An organism requiring at least 0.2M concentrations of salt (NaCl) for growth
An organism that can thrive at temperatures between 80–122 °C, such as those found in hydrothermal systems
An organism that lives underneath rocks in cold deserts
An organism (usually bacteria) whose sole source of carbon is carbon dioxide and exergonic inorganic oxidation (chemolithotrophs) such as Nitrosomonas europaea; these organisms are capable of deriving energy from reduced mineral compounds like pyrites, and are active in geochemical cycling and the weathering of parent bedrock to form soil
capable of tolerating high levels of dissolved heavy metals in solution, such as copper, cadmium, arsenic, and zinc; examples include Ferroplasma sp. and Cupriavidus metallidurans
An organism capable of growth in nutritionally limited environments
An organism capable of growth in environments with a high sugar concentration
An organism that lives optimally at high hydrostatic pressure; common in the deep terrestrial subsurface, as well as in oceanic trenches
An organism that qualifies as an extremophile under more than one category
An organism capable of survival, growth or reproduction at temperatures of -15 °C or lower for extended periods; common in cold soils, permafrost, polar ice, cold ocean water, and in or under alpine snowpack
Organisms resistant to high levels of ionizing radiation, most commonly ultraviolet radiation, but also including organisms capable of resisting nuclear radiation
An organism that can thrive at temperatures between 60–80 °C
Combination of thermophile and acidophile that prefer temperatures of 70–80 °C and pH between 2 and 3
An organism that can grow in extremely dry, desiccating conditions; this type is exemplified by the soil microbes of the Atacama Desert
If we are not to apply the scientific observations we have discovered to be repeatable.