[baudrunner]

Hi, sillysally,

Welcome to the quest.

I don't know how you feel about mixing science and theoretical speculation with the pragmatic because that's where I come from. I tend to rain on people's parades.

Any reference, usually biblical, to people living outrageous ages like 800 or 900 years as found in the Book of Genesis actually refers to the phases of the moon. The "year" that is being referred to is actually a month. The primitive minds of those who wrote the stories so many thousands of years ago did not accept real science, likely did not even speak the language of their masters (the Egyptians) who did have some astronomical knowledge, and were not aware of seasonal changes in a land where it was only periodically hot and then somewhat less hot, and not predictably at that. The phases of the moon are an excellent reference in telling time. Try dividing 12 into those large three digit numbers and you get an age which is normal for any time for any reasonably healthy individual who eats well. We only live somewhat longer now because we have better medicines.

You are actually wondering why we can't live forever. I have expounded elsewhere on this site as to the process that determines life to exist but I will skip most of it and give you the short answer. The evolution of a single-celled life with a few nucleotide sequences in them to a single-celled life with a nucleus, or a eukaryote, occurred over a span of 2 billion years. The evolution of eukaryotes into the simplest multi-cellular life, ie.- a bilateral (left and right side) creature with a mouth and an anus, now long extinct, occured over a span of 1.5 billion years; and the evolution from that simple lifeform to humans occurred over a span of 650 million years. So you see, the simple fact is that evolution is an accelerating process. If life had become manifest into one giant infinitely existing sentient intelligent being it would have become obsolete over time. Life must of needs be finite, and continuously in production in order to meet the requirement that it manifests as a matter of course for perpetuity, given the conditions that allow it to do so.