This influential, yet controversial idea requires that the mixture of species on Earth at any moment acts as a collective organism that continuously (yet unwittingly) tunes Earth's atmospheric composition and climate to promote the presence of life... But I'd bet there are some dead Martians and Venusians who advanced the same theory about their own planets a billion years ago.

'As a fraction of your tax dollar today, what is the total cost of all spaceborne telescopes, planetary probes, the rovers on Mars, the International Space Station, the space shuttle, telescopes yet to orbit, and missions yet to fly?' Answer: one-half of one percent of each tax dollar. Half a penny. I'd prefer it were more: perhaps two cents on the dollar. Even during the storied Apollo era, peak NASA spending amounted to little more than four cents on the tax dollar.

I'm a fan of the planets in any combination. When I was born, Mercury, Venus, Jupiter, Saturn, Uranus, Neptune, Pluto, the Sun, and the Moon were all in the sky.

Trillions of years into the future, when all stars are gone...all parts of the cosmos will cool to the same temperature as the ever-cooling background. At that time, space travel will no longer provide refuge because even Hell will have frozen over. We may then declare that the universe has died-not with a bang, but with a whimper.

It's progress I think, that science has joined philosophy, metaphysics & religion as subjects drunk people argue about in bars.

For me, one of the most fertile consequences of the space program is the extent to which it stimulates people to innovate because they want to create a different tomorrow than what they're living in today. And it's that culture of innovation that spawns entirely new economies.

A television advertisement must illustrate the scientific method to substantiate any claim.... That is why stains are lifted, ring-around-the-collar is removed, paper towels become soaked, excess stomach acid is absorbed, and headaches go away-all during the commercial.