ill start with a quote. (sorry Guppy but this may be a little long)
"Astronomy leads us to a unique event. a universe which was created out of nothing,one with the very delicate balance needed to provide exactly the conditions required to permit life, and on which has an underlying (one might say supernatural) plan."- Nobel Laureate Arno Penzias
Most astronomists however, dont agree. They agree with the ego deflating idea of copernicus. We are an average rock floating around an average star in an average galaxy.( i realize i did agree with this idea earlier in the thread, but i was having a "bad" day. but im having a good day right now, so i decided to do a little research) This idea was so cemented that we infact in the 70s beamed a message to a globular cluster known as M13, a concentration of 250,000 stars. The message, one of greeting, would take more than 20,000 years to reach its target.
This idea of "mediocrity" is however beginning to change. Many scientists are beginning to study the scores of of "coincidences" that make intelligent life possible on earth. A book titled "Rare Earth", marshals evidence from a wide range of scientific disciplines to build its case that "not only intelligent life, but even the simplest animal life may be exceedingly rare in our galaxy and in the universe." The authors call the conclusion "inescapable" that earth is a rare place indeed. David Levy also said that "As we know it on earth, complex life might be very rare and precious." More and more scientists are observing the incredible ways in which our planet manages to fulfill a large number of finely balanced criteria that are absolutely crucial to supporting a habitat suitable for intelligent life to flourish.
Most scientists believe that as long as you have water, life would appear. It is true that the universal solvent is needed for proper reactions to take place. And arbon which serves as the core atom of the molecules of life. but still more then that is needed. Humans need 26 essential elements, even bacteria need 16. The problem is that not just any planet will provide all of those required ingredients in the correct forms and amounts. Science fiction writers have popularized the idea that life on other planets and galaxies may have take on a radically different form, for example sillicon based life-forms instead of carbon based. The problem is that you cant get other elements to stick together in sufficient number and complexity like carbon can. furthermore, you cant get other liquids to dissolve as many different chemicals as water can. Plus, ther are around half a dozen different properties of both water and carbon that are optimal for life. And frankly, no other combination comes close.
A good argument against the idea of a "special" planet is number, there are trillions upon trillions of stars with undoutbtedly trillions of terrestrial bodies revolving around them. Mathematically, it seems likely that there are many earth-like habitats. But a concept known as the galactic habitable zone refutes the math. The idea basically states that you cant have a habitable planet anywhere for there are too many threats to life present in most places in the galaxy. Furthermore, only spiral galaxies are conducive to life because they provide habitable zones between arms. Also the safe zones are found relativley halfway between the edge of the and the nucleus of the galaxy. To close to the center, and radiation is too prevalent to allow life. To far away, and there arent enough heavy elements to allow for an earth like planet.
So in closing, earth may be more special then we previously believed. So we may indeed be rare.
"Astronomy leads us to a unique event. a universe which was created out of nothing,one with the very delicate balance needed to provide exactly the conditions required to permit life, and on which has an underlying (one might say supernatural) plan."- Nobel Laureate Arno Penzias
Most astronomists however, dont agree. They agree with the ego deflating idea of copernicus. We are an average rock floating around an average star in an average galaxy.( i realize i did agree with this idea earlier in the thread, but i was having a "bad" day. but im having a good day right now, so i decided to do a little research) This idea was so cemented that we infact in the 70s beamed a message to a globular cluster known as M13, a concentration of 250,000 stars. The message, one of greeting, would take more than 20,000 years to reach its target.
This idea of "mediocrity" is however beginning to change. Many scientists are beginning to study the scores of of "coincidences" that make intelligent life possible on earth. A book titled "Rare Earth", marshals evidence from a wide range of scientific disciplines to build its case that "not only intelligent life, but even the simplest animal life may be exceedingly rare in our galaxy and in the universe." The authors call the conclusion "inescapable" that earth is a rare place indeed. David Levy also said that "As we know it on earth, complex life might be very rare and precious." More and more scientists are observing the incredible ways in which our planet manages to fulfill a large number of finely balanced criteria that are absolutely crucial to supporting a habitat suitable for intelligent life to flourish.
Most scientists believe that as long as you have water, life would appear. It is true that the universal solvent is needed for proper reactions to take place. And arbon which serves as the core atom of the molecules of life. but still more then that is needed. Humans need 26 essential elements, even bacteria need 16. The problem is that not just any planet will provide all of those required ingredients in the correct forms and amounts. Science fiction writers have popularized the idea that life on other planets and galaxies may have take on a radically different form, for example sillicon based life-forms instead of carbon based. The problem is that you cant get other elements to stick together in sufficient number and complexity like carbon can. furthermore, you cant get other liquids to dissolve as many different chemicals as water can. Plus, ther are around half a dozen different properties of both water and carbon that are optimal for life. And frankly, no other combination comes close.
A good argument against the idea of a "special" planet is number, there are trillions upon trillions of stars with undoutbtedly trillions of terrestrial bodies revolving around them. Mathematically, it seems likely that there are many earth-like habitats. But a concept known as the galactic habitable zone refutes the math. The idea basically states that you cant have a habitable planet anywhere for there are too many threats to life present in most places in the galaxy. Furthermore, only spiral galaxies are conducive to life because they provide habitable zones between arms. Also the safe zones are found relativley halfway between the edge of the and the nucleus of the galaxy. To close to the center, and radiation is too prevalent to allow life. To far away, and there arent enough heavy elements to allow for an earth like planet.
So in closing, earth may be more special then we previously believed. So we may indeed be rare.
