Before deciding what to write, I checked my trustworthy "Random House Dictionary of the English Language" to see what the definition of life really is. I was quite surprised with the number of definitions given for the word "life". Basically it comes down to this;
"Life is the condition that distinguishes animals and plants from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally". If I am interpreting that correctly, it supports my theory, that life on other planets would not have to be "life as we know it", as many scientist indicate when discussing the possibility of life on another world. Obviously, life has the ability to adapt to whatever conditions are present, with those changes originating internally.
I grew up being told and believing we are all there is and accepted it as fact. After all what information did I have to question it? A few years later however, when word about flying saucers, (UFOs), started filtering into my learning process, the "fact" began to become questionable. As my interest in ufology strengthened, and science began to take a closer look at the possibilities of life elsewhere, and discover previously unseen things in our universe, I became more aware to the fact that, surely we are not all there is, in this gigantic universe. I for one cannot be that egotistical to think that life only exists on earth. Is it life as we know it elsewhere? No one knows that yet, but I would wager, probably not, and I see no reason why it would have to be. We are tremendously limited in our ability to think in ways not familiar or "comfortable" to our teaching and method of thinking.
The case against life elsewhere:
Since (in my opinion), this will be the shorter of the two responses, I've chosen to discuss it first. As with all research related to ufology, there are always two sides to every lead, investigation and theory.
Recently two professors at the University of Washington, Peter Ward, with impressive credentials in paleontology and Donald Brownlee, a noted astronomer, co-authored a book, (Copernicus Books), entitled, "Rare Earth", (Why Complex Life is Uncommon in the Universe). They based some of their findings on a study of how life formed on our planet and how several things had to happen at specific times and precisely so, in order for life to evolve over several billion years. They are careful not to rule out life on other planets as a possibility, but state life may exist as microbes and not much more.
Some of the reasons they give for their observation are as follows:
• Our moon stabilizes the earth's axis and helps control our climate.
• The location of our solar system in our own galaxy prevents over exposure from our sun.
• Most stars in the universe are smaller than our sun and that would require planets to orbit closer to their sun to obtain necessary heat.
• Since Jupiter's orbit is in the same solar plane as our earth, it protects us from being hit by many things such as asteroids and comets.
• Having only one sun in our system provides a more stable orbit by the earth around the sun.
• Our distance from the sun is such that an atmosphere and liquid water can form and be maintained.
So these two professors, at no fault of theirs, are making assumptions based on the only planet we know anything about that has intelligent life---our earth. I can't fault them for that, since that's all any of us have to work with.
The case for life elsewhere:
In the above mentioned book "Rare Earth", Frank Drake's Equation is taken to task as assumptions. Are those two authors not also assuming that life on other planets would have to develop the same way as it did on earth, since that is all they can base their information on?
The Drake equation ( N = N* fp ne fl fi fc fL) was developed in 1961 and it is also based to some extent on guesswork, but the more we learn about the universe, the more accurate the results obtained with the equation will become.
Based on the Drake equation, the following is currently believed to be fairly accurate:
• The number of stars in our galaxy are around 200 billion (that's billion with a "B").
• Also used in the equation is the number of stars that would have planetary systems, how many of those planets could support life, and on how many of those planets would life evolve, with an intelligent life.
Our space program and those of other nations have been for several years, sending probes out into our solar system, and among other things being accomplished, they are looking for other life on those adjacent planets to ours. The Hubble telescope has given us glimpses at objects that a few years ago no one dreamed we'd ever be able to see. I think many of us would like to know (and probably even hope), that we are not the only living thing in the universe. Our knowledge is so limited however, that we are still searching our closest neighbor for that information. I'm not implying that we haven't had success in some of our ventures, but when you think of the possibility that there may be 200 Billion stars just in our galaxy, according to Drake's equation, surely some of which can have planets similar (or not similar) to ours, the odds are pretty high for finding other life forms.
I envy those being born today for what they may learn in their lifetime, while on the other hand, I hope that we leave that opportunity for them to learn. Technology is proceeding forward at a faster rate than it ever has in our existence on this planet. Some researchers indicate that our planet earth is about 4.6 billion years old. The oldest known direct evidence of life on earth is a fossilized bacteria found in 3.5 billion-year-old rocks from Western Australia, as announced by J. William Schopf of the University of California at Los Angeles in 1993. The technology we enjoy today has only been developed in the past 100 years, so can we imagine what will be forthcoming in the next 100 years?
We are unique in the location of our planet with in our solar system and galaxy, which surely had a vital affect on it being habitable. What we have developed into has been our choice. What we leave for our children and grandchildren is also our choice. I hope we make the right decisions.
I really don't believe the contact from other life forms will come to us by means of radio communication as that seems, to me, to be a primitive means of communicating. Rather I'm hopeful that actual physical contact will take place. We might have to prove to "them" that we're worthy of being contacted, however, and I'm not sure at this point that we are.
Why Complex Life is Uncommon in the Universe
Their rare Earth hypothesis predicts that while simple, microbial life will be very widespread in the universe, complex animal or plant life will be extremely rare. Ward and Brownlee admit that "It is very difficult to do statistics with an N of 1. But in our defense, we have staked out a position rarely articulated but increasingly accepted by many astrobiologists."
Their new science is the field of biology ratcheted up to encompass not just life on Earth but also life beyond Earth. It forces us to reconsider the life of our planet as but a single example of how life might work, rather than as the only example.
The revolution in astrobiology during the 1990s was twofold. First, scientists grew to appreciate how incredibly robust microbial life can be, found in the superheated water of deep-sea vents, pools of acid, or even within the crust of the Earth itself. The chance of finding such simple life on other bodies in our solar system has never seemed more realistic. But second, scientists have begun to appreciate how many unusual factors have cooperated to make Earth a congenial home for animal life: Jupiter's stable orbit, the presence of the Moon, plate tectonics, just the right amount of water, the right position in the right sort of galaxy. Ward and Brownlee make a convincing if depressing case for their hypothesis, undermining the principle of mediocrity (or, "Earth isn't all that special") that has ruled astronomy since Copernicus.