Life !!!- One of the biggest mysteries of all times....

The Earth began some 4.5 billion years ago. During this early era, approximately one billion years long, the newly-borning Earth was pummeled mercilessly by meteorites. This was the so-called "Hadean Period" (and well named at that!), a "hell-ish" time indeed when the Earth's surface was periodically broiled, flash-fried so to speak. Incoming asteroids of sufficient size would actually vaporize, themselves and the part of the surface they impacted and this would turn into a seering plasma that would tsusami around the globe - not a pretty picture. Not to mention volcanic eruptions.

Abiotic Production of Organic Molecules
The classic experiment demonstrating the mechanisms by which inorganic elements could combine to form the precursors of organic chemicals was the 1950 experiment by Stanley Miller. He undertook experiments designed to find out how lightning--reproduced by repeated electric discharges--might have affected the primitive earth atmosphere. He discharged an electric spark into a mixture thought to resemble the primordial composition of the atmosphere. In a water receptacle, designed to model an ancient ocean, amino acids appeared. Amino acids are widely regarded as the building blocks of life.

Although the primitive atmosphere is no longer believed to be as rich in hydrogen as once thought, the discovery that the Murchison meteorite contains the same amino acids obtained by Miller, and even in the same relative proportions, suggests strongly that his results are relevant.

Others have made similar experiments. A group at the Department of Chemistry and Biochemistry at the University of California, San Diego, exposed sulfur-bearing molecules like those thought to have been present before the Earth formed to low levels of light. The presence of the light was enough to generate organic compounds - molecules containing carbon, which form the chemical basis of life as we know it.

The new compounds had a distinct isotopic (atomic makeup) signature, not normally found on Earth. In fact, the peculiar part is that these isotopes have only been found one other time, in compounds removed from the Murchison meteorite.

So that's what the scientists could say about life and the probable origin of life.....

But now I am left with more questions than when I started out with.

If I can sum up the above content till now - A couple of different chemical molecules, presence of light/ electricity and you are left with Amino Acids that is supposed to be the building blocks of life here on earth.

By my question remains -

How do we begin to define "Life" and at what precise moment would the first scientist exclaim

"Hey !!! That's Life !!!!. ?I have created Life from Organic chemicals !" ???

The Merriam-Webster dictionary defines life as:

"a: the quality that distinguishes a vital and functional being from a dead body

b : a principle or force that is considered to underlie the distinctive quality of animate beings

c : an organismic state characterized by capacity for metabolism, growth, reaction to stimuli, and reproduction"

Needless to say that I am not satisfied with the above definition.

• "Quality that distinguishes"
• "A vital and functional being"
• "A principle or force"
• "distinctive quality of animate beings"
• "organismic state"

I am sure I would need to have a look at the definitions for the above terms again and that would still leave me with more question that answers.

I have always thought that the distinction between life and non-life is a very blurred line. This significant blurred line is where we are not sure if we can define the object of study as life or non-life.

Some facts first:

• The Universe has been around for approximately 13.7 billion years. That's a long time !
• Till date, close to 300 (if not more) extra-solar planets discovered in our viscinity (in astronomical terminology).
• A couple of these newly discovered planets are considered habitable for life to exist.
• There are 200 billion stars in the Milky-Way Galaxy ! and the probability of finding a planet
  

Thus the chances of life on earth originating outside our planet is a significant probability. Life may have come piggybacking on an Asteriod that struck earth close to 2 billion years back. How it has arrived though is not the important question.

THE QUESTION IS AND IT REMAINS - When do we know that we have found life ?

I am not talking about human, other animals, plants or even Viruses and Bacteria. We know for sure that these beings are alive. They can reproduce, grow, react to stimuli and have the metabolism function within them.

But imagine looking at the earliest of molecules when all this started !
I can't begin to imagine how in heaven's name can a couple of organic molecules can "start" reacting to their environment ? Why would the first molecule would want to reproduce ? Why would "it" want more of "its" same ? What significance would "its" outcome be within the environment in which it is residing ? Do we call its moment of first "realization" (that it would need to reproduce) - "the first life" in this universe ?

If not, which is the moment ?

If its not reproduction, then what is it ?

Was it the realization that it needs "food" to "grow" . That is, its ability to grow ? have more of what it is already and have more food than it used to earlier ?

It's the first realization that I was and am always so very curious to know more about............

I am assuming that once we exclaim "hurrah !!! this is life" the evolution over the next billions of years can be explained with considerable ease....

There is something that happens right here on Earth that is equally baffling to me....

"The Birth of the new born"

I am not referring to the baby coming into (the delivery process) this world, but near to the moment it was conceived in the uterus of a mother....

The sperm of the male "fertilizes" the egg ovary residing in the uterus of a mother.

Sounds simple, isn't it ? But we fail to realize that both the sperm and the egg don't have all the attributes of the baby that it eventually leads to...

So when is it that the growing fertilized egg has all the attributes of life per se as we know it....

It is, as if, suddenly the force comes within to jump start the process.....

Do I continue to believe in God till all my questions are answered ? I am guessing it would be a couple of my after-lives when someone does come up with definite answers to these ! I look forward to that day...

The first moment of "realization" is truly a fantastic moment for all "life" as we know it....