The strange new world of Nanoscience, narrated by Stephen Fry - YouTube#at=35#! Meaning of Halflife. I'd like to illustrate what this really means.
If living creatures had halflives the way radioactive atoms do, the world would be a very different place. What do you mean? Suppose there's an alien species with a halflife of, say, 70 years. You randomly pick out 16 baby aliens and track them to see how long they live. After 70 years, of course, 8 of them will still be alive. Through the Wormhole: Can We Live Forever?
The Brain.