The aliens on the TV show "Battlestar Galactica," which starts its final season Friday night on the SciFi Channel, aren’t your usual extraterrestrial baddies: They’re highly evolved robots, originally created by the humans they’re now fighting against. How highly evolved? The robots are way sexier than the humans.
Some aspects of the "Galactica" universe may be as bogus as other science-fiction creations (such as spaceships with artificial gravity that instantly jump from one star system to another). But when it comes to the idea that the first intelligent aliens we meet may actually be machines, astronomers say the show is definitely on the right track.
"There are two kinds of encounters with aliens you can have," said Seth Shostak, senior astronomer at the California-based SETI Institute. "Either you pick up a signal, or you pick them up on the corner. But I think it's safe to say that in both instances they will be synthetic. They will be artificial constructions."
That may not be obvious to science-fiction fans who have grown up with soft, squishy aliens like "E.T.," or even noble humanoid visitors like Michael Rennie's Klaatu in "The Day the Earth Stood Still." But Shostak arrives at his conclusion by looking at how rapidly we're developing our own breeds of smarter machines.
"Within another 100 years we will presumably be making thinking machines ourselves," he said. And because we're almost certainly the new kids on the block when it comes to interstellar communication and travel, any civilization that makes contact with us would likely be much farther along.
Such a civilization could create swarms of robo-broadcasters to ping the surrounding habitable star systems, or "one giant machine that's sitting somewhere just belching out the local weather report," Shostak said. If the aliens felt the need to send out actual emissaries, an intelligent machine would be best suited for survival over the time scales required for interstellar flight.
"The chances that it's going to be a little green guy with big eyeballs is pretty remote," Shostak said.
Robot-human hybrids
Astronomer Jeffrey Bennett, author of the newly published book "Beyond UFOs," agreed with Shostak's assessment. In his book, Bennett speculates that there might be 100,000 Earthlike planets in our galaxy where intelligent life could have arisen over the past 5 billion years. If you average that out, that comes to one galactic civilization for every 50,000 years. His conclusion? The typical alien civilization will be at least 50,000 years older than ours.
"I find myself personally hesitant to imagine anything that far advanced," Bennett told me. "No one imagined the Internet 50 years ago, and we're trying to imagine what things would be like after 50,000 years of technological development? I just don't think we could make really good guesses, other than to say it will be incredible."
He was willing to go along with the idea that an advanced alien species might be a hybrid of biology and cybernetics - an idea that I addressed a couple of years ago in a highly speculative look at future evolution. "When you look far out, you start to ask yourself where the robot ends and where the organism begins," Bennett said.
However, Bennett and Shostak were both pretty sure that a real alien cyborg wouldn't fill out a red dress the way Six (played by Tricia Helfer) does on "Battlestar Galactica."
"I think people get it wrong when they assume the aliens will be young lovelies," Shostak joked.
Sex and robots
Of course, the "Galactica" writers can explain why the cyborgs (known as Cylons on the show) are so darn good-looking: Because the robots were created by humans in the first place, they'd have a good idea what templates to use if they decided to transform themselves from the shiny toasters of 1978's original "Galactica" into sexy spies.
That sexiness applies to the Cylons' function as well as their form. Without getting too deeply into the series' spoilers, let's just say that the robots are capable of doing anything humans do - including falling in love, getting married and giving birth.
"Battlestar" isn't the first to address this in science fiction, of course. Romance with robots is a familiar plot line to anyone who has seen "Star Trek," "Blade Runner" or other sci-fi classics. But how realistic is the idea?
This topic isn't often addressed by astrobiologists. However, David Levy, an artificial-intelligence researcher at the University of Maastricht, explored the subject of robot-human intimacy in depth last year. His doctoral thesis on sexbots spawned a book titled "Love and Sex with Robots" - in which he contends that the age of robot-human unions may be closer than you think.
"My forecast is that around 2050, the state of Massachusetts will be the first jurisdiction to legalize marriages with robots," Levy told LiveScience.
It may sound outlandish - but then, so does the idea of a pregnant man.
Aliens 'R' Us?
So far, we've been talking about intelligent aliens - the kinds of aliens that make for the complex relationships and ripped-from-the-headlines relevance "Battlestar Galactica" has become famous for.
But the first aliens we're likely to encounter could be in our own celestial backyard, and much harder to figure out. Perhaps we'll find microbes deep beneath the Martian surface. Maybe there are critters lurking in the hidden seas of Jupiter's moons (say, Europa or Callisto) or Saturn's moons (Enceladus or Titan).
"The most likely place where we'd get the first evidence would be from Mars," Bennett said, simply because that's the closest potential target, with an armada of probes already looking for clues. One more probe, the Phoenix Mars Lander, is due to join the search next month.
If a future spacecraft does find something, determining whether it's alien life could be tricky. First of all, is it life, or merely a geological process? The debate over the "nanofossils" found on a Martian meteorite more than a decade ago illustrates how difficult answering that question can be.
If the signature of life happened to be earthlike, you'd have to ask whether that life was truly alien. "There's the possibility of terrestrial contamination, not necessarily from spacecraft, but from meteorites that have flown between the planets," Bennett said.
In fact, some scientists have speculated that life as we know it could have gotten its start on Mars, and then was transferred to Earth before the Red Planet turned dry and cold. If that's the case, we all could be aliens. And darn good-looking ones, too.
An extended version of this report appears in Cosmic Log at msnbc.com. The SciFi Channel is owned by NBC Universal, which is a partner along with Microsoft in the msnbc.com joint venture.