I think it is possible for ordinary people to choose to be extraordinary.

Physics is really figuring out how to discover new things that are counterintuitive, like quantum mechanics. It's really counterintuitive.

Many things are improbable, only a few are impossible.

It would take six months to get to Mars if you go there slowly, with optimal energy cost. Then it would take eighteen months for the planets to realign. Then it would take six months to get back, though I can see getting the travel time down to three months pretty quickly if America has the will.

You could warm Mars up, over time, with greenhouse gases.

If we drive down the cost of transportation in space, we can do great things.

It's not as though we can keep burning coal in our power plants. Coal is a finite resource, too. We must find alternatives, and it's a better idea to find alternatives sooner then wait until we run out of coal, and in the meantime, put God knows how many trillions of tons of CO2 that used to be buried underground into the atmosphere.