Seth Shostak

About the only things that are unique to Earth are our biota and our culture. If aliens ever come here, they'd most likely be either biologists or music fans. Neither one has much reason to antagonize our armed forces.

Are two eyes, four appendages and an upright posture really essential for any creature that can ace the galactic SAT's? Maybe not. In fact, I'd venture that any aliens we ever detect or (less likely) encounter will look quite different than this self-referential stereotype.

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.

People don't learn science in movies. You don't go to the movies thinking, 'I hope I learn some quantum mechanics this afternoon.' But on the other hand, movies are instrumental and influential in getting young people interested in science.

Our computers double in capability on time scales of only a few years. It's hardly outrageous to believe that we will successfully develop thinking machines within a handful of decades, or at most a century or two. If that happens, these artificial sentients will quickly leave us behind.

According to 'Star Trek' mythos, Starfleet Command - operational headquarters for a flotilla of craft that keep the cosmic peace - is located in San Francisco's Presidio, in the shadow of the Golden Gate Bridge (still carrying traffic, even in the 23rd century).

The bottom line is that finding orphan planets - small, faint, and located who-knows-where - is not for the faint of heart. The task is comparable to observing a match flame at the distance of Pluto. The WISE satellite, a hi-tech, space-based infrared telescope especially suited for such work, has found only a few.

The total number of people that do a job that has the same description as mine in the entire world is fewer than 10. There's a lot of effort looking for life in space - that's a lot of what NASA does, but they're not necessarily looking for the kind of life that can hold up its side of a conversation.

Mars still remains the astrobiology community's number one choice for 'nearest rock with life,' but there are many researchers who argue that the moons of Jupiter are better bets. In particular, Europa, Ganymede, and Callisto are all thought to hide vast oceans of liquid water beneath their icy, outer skins.

It's always a tough call deciding whether, as a scientist, you should argue publicly with the creationists. It's a dilemma that I encounter frequently in another subject area: Does it make sense to bandy words with someone from the UFO community?

Every day, the temperature of Sol's surface increases by five billionths of a degree, a change of no consequence for thousands of millennia to come. But a few hundred million years from now, barring a fix by our descendants, this relentless heating will substantially change Earth's biosphere in ways that might not be survivable for us.

Consider: Life arose on Earth close to four billion years ago. Four billion years of slithering, swimming, and soaring life forms. But only in the last 200 thousand years has a species arisen that can fathom the laws of nature and build hardware able to signal its presence.