jonathanbgood

Yes, their birth rate assumptions would only yield the population milestones they suggest if the life expectancy was significantly below the reported level.

Thanks for pointing it out - we fixed this to 200,000 B.C.

We use the world population and average life expectancy to calculate births in a year. To connect these point estimates at the varying times in history we use a bounded exponential growth model for births.

Last night an Egyptian in Toronto, who felt powerless to help in the midst of the bloodshed, asked if we could create a place for Egyptians and the world to remember the lives that have been lost in the protests in Egypt.