How the new economics of space exploration changes everything

It costs about $10,000 per pound, to put a person into orbit and $1,000,000 per pound to send a person to Mars. That's a lot of money, especially in these current times of economic austerity. So how are we going to explore space and build an insurance policy, so to speak, to save Earth from global warming? The acclaimed theoretical physicist Michio Kaku says that help could come not from NASA alone but with help from the private sector. Specifically, he posits that inventor, free-thinker, and all-around Silicon Valley disruptor Elon Musk "has the vision, the energy, and the checkbook" to turn these seemingly far-out ideas into a reality. Michio's latest book is The Future of Humanity: Terraforming Mars, Interstellar Travel, Immortality, and Our Destiny Beyond Earth.