“It bears mentioning that the Milky Way is only one of 150 billion galaxies visible to our telescopes - and each of these will have its own complement of planets.”

“The Moon stabilizes Earth's obliquity. Well, almost. The tilt actually varies between 22 and 24.5 degrees - and the variation is enough to induce such environmental inconveniences as the occasional ice age. Without the Moon, it might be much worse.”

“We can never prove that we're alone in the universe. But the Allen Telescope Array could prove that we're not.”

“Disasters happen. We still have no way to eliminate earthquakes, wildfires, hurricanes, floods or droughts. We cope as best we can by fortifying ourselves against danger with building codes and levees, and by setting aside money to clean up afterwards.”

“Ever since the infamous quiz show scandals of the 1950s, the feds had insisted that TV game shows be honest - or that at least they didn't cheat. So as a 'Dating Game' bachelor, I didn't know what I was going to be asked. The other bachelors and I were required to concoct our answers in real time.”

“'Dating Game' wasn't social commentary, political analysis, Shakespearean-level drama or even blunt-force comedy. It was just the televised equivalent of meeting someone at a bar. But it appealed to our most basic Darwinian instinct: selecting a good mate. You can't go wrong when a show's premise is hard-wired into human DNA.”

“It seems obvious that if a species has the brainpower for speech, along with the sort of appendages that can manipulate a pair of pliers, it will eventually blunder into science, technology, and radio.”

“The space elevator's not just another competitive technology, promoted by people who simply like the idea of diminishing the luster of the thrusters. It would open wide the doors to space.”

“Most of the things at the zoo don't look like us. We're one design that works. Our chimp pals sort of look like us, so that's a different take on the same basic design. But fish don't look like us, and giraffes don't. They look a little like us, but not too much. And insects certainly don't look like us, and they work just fine.”

“While human space travel is daunting, machines - with their indefinitely long lifetimes - could travel the galaxy. It might make little difference to them that bridging the distance from one star to the next could take hundreds of thousands of years or more.”

“It's hardly a secret that I'm skeptical of declarations that the aliens are out and about on our planet. Still, I try to answer every one of these mails and phone calls because, after all, it's not a violation of physics to travel from one star system to another.”