Sue Armstrong: Unraveling the mysteries of borrowed time

The science of aging is rapidly evolving. Many of us are more aware of our capacity to live a long healthy life, than ever before. But the quest to understand human longevity - and perhaps figure out how we can slow down the process - is still a huge work-in-progress. Why do we age? Is it due to wear and tear on our bodies, is it all predetermined by our genes - or is there an invisible killer all around us, such as toxins in the environment, that is slowly eating away at our lifespan? These ...