One Planet examines the ethical and practical implications if people begin to live for 200 years and beyond.

David Eagleman is an American neuroscientist whose book: Sum: Forty Tales from the Afterlives, imagines a world where everyone lives for centuries, even as long as beyond 300 years.

He has written a funeral speech, from an imagined future, in which a relative has died prematurely at the age of just 122 years.

The article has a picture of a person who is a 120 and looks that age—meaning, she looks just awful. But this is a misrepresentation of what it will be like to live for 200 or more years. If that kind of longevity becomes a reality, it will mean one thing: the great extension of time that a human life spends in its youth. It will not mean, as the picture implies, that you will be old forever. Being old for 200 years is utterly useless. It is youth that matters, and a life that can span two centuries will not be biologically possible without the lengthening of the period which contains the greatest amount of health, resilience, and strength.