The actual root cause of aging was discovered some time ago. When cells die, and are replaced by new cells, there is always a very tiny bit of degradation in the copy. Sort of like what happens if you copy a xerox from a xerox, from a xerox, etc.
It was theorized, that if it were possible to make new cells that were perfect copies of the cells they were replacing, then logically, there should be no aging.
Long story short, experiments with mice and other animals proved the theory was correct. Here's an excerpt of an article that explains the science behind this:
"Inside the center or nucleus of a cell, our genes are located on twisted, double-stranded molecules of DNA called chromosomes. At the ends of the chromosomes are stretches of DNA called telomeres, which protect our genetic data, make it possible for cells to divide, and hold some secrets to how we age and get cancer.
Telomeres have been compared with the plastic tips on shoelaces because they prevent chromosome ends from fraying and sticking to each other, which would scramble an organism's genetic information to cause cancer, other diseases or death.
Yet, each time a cell divides, the telomeres get shorter. When they get too short, the cell no longer can divide and becomes inactive or "senescent" or dies. This process is associated with aging, cancer and a higher risk of death."
Each time a cell reproduces the telomeres are cut in half. At a certain pre determined point the cell will cease to replicate itself and die off(apoptosis). As far as I know though cancer cells do not lose telomeres and continue to make complete duplicates including a full set of telomeres.