The world can now maintain an acute infection in a way that is unprecedented in the history of life on our planet.

Many people on our planet right now despair; they think we've reached a point where we've discovered most of the things. I'm going tell you right now: Please don't despair.

If an alien visited Earth, they would take some note of humans, but probably spend most of their time trying to understand the dominant form of life on our planet - microorganisms like bacteria and viruses.

Phone networks can capture life on our planet.

Big History studies the history of everything, offering a way of making sense of our world and our role within it.

Poverty and lack of education are ruining our planet.