even the sun is meant to die in a few million years. *snip* The Earth does not even have the resources to support the present number of humans.
Er, you're off by a factor of about a thousand....the sun is set to keep shining at its present rate for another 4 to 5 billion years...The Earth can easily sustain the current number of humans living on the planet; the amount of surplus food produced by the united states alone could feed most of the starving people in the world; only lack of effort on humanity's part is preventing the hungry from eating.
Well, now we know Bob Barker's secret...
And Dick Clark's as well.
The only way to make humans live more than about 130 is to make cells out of a longer lasting matterial like steel, but then we would be machines and no longer human. The DNA also decays so it is imposible to 'rebuild' someone after a certain age, thats why bringing dinosaures back to life Jurrassic Park style is impossible.
Also 3000 years ago people were living way past 100, it was only from about the 16th century AD that people started living 30 years.
I'm not sure you understand the composition of animal cells; the phospholipid bilayer membrane that makes up the cell membrane is constantly being repaired and rebuilt by the cell, as are the proteins and cholesterols embedded in it (cholesterols are actually responsible for the flexibility and some of the strength of the membrane). The other parts of the cell such as the cytoskeleton and various organelles are also repaired and replaced through the life of the cell, by the cell (some of the organelles, like mitochondria actually replicate and repair themselves independently of the cell).
DNA in healthy cells is constantly being repaired and "proof-read" to correct mistakes from random mutations and replicational errors, (in an average cell, point mutations in nuclear DNA occurs at the rate of about 100 per day. However, due to the cells ability to repair its DNA through the action of DNA polymerase 1, 2, and 3 (only 1 has proof-reading activity though) the rate of mutation not corrected by the cell is around (sorry i can't remember exactly, molecular bio was a total drag) 1 in 10^12 mutations.) The main limiting factor in the life of the cell is how many times the chromosomes can replicate before information is lost. Information is lost on the ends of the chromosomes during mitosis, however the ends of chromosomes are repetitive noncoding DNA known as telomeres. after enough replications the telomere DNA has been lost, and DNA coding for proteins begins to get lost. In experiments with cells treated to replicate and replace their telomeres, scientists have created cells that are in effect immortal, and they do not exhibit signs of aging. What I'm saying here is that its not the individual parts of the cell wearing out, or the fragility of DNA (in a cellular environment it will last quite intact for an extremely long time...there are Redwood trees over 1,000 years old, and they're DNA based life forms just like us), that is the limiting factor in human life
As for people 3,000 years ago living "way past 100" I'm afraid I'm going to have to ask you for proof positive of that. I'm sure a very, very, very select few individuals hit the 100 mark, but they are extremely few and far between. I believe there are verified records of an Egyptian pharoh living to the age 92, and that was an extraordinary event. "way past 100?" I don't think so. In any event, the life expectancy in the Roman Principate, which was pretty much the height of western civilization at the time, from (sorry about the inexactness of the dates, I really hated Roman history) ~40 BC to ~530 AD the average life expectancy was around 45, which wasn't a whole lot higher than it was in the previous centuries. In fact it wasn't until the 20th century that the average life expectancy increased to over 60 for anyone.
