Seth Shostak on the Set of 'The Day the Earth Stood Still'
Promotional poster for 'The Day the Earth Stood Still,' 2008 version.
Credit: 20th Century Fox

I met my first alien, and he looked like a tall Canadian.

Indeed, he was Canadian. It was Keanu Reeves, suited up to play the part of a visiting extraterrestrial by the name of Klaatu.

This was months ago, when I was ushered into a large building in an industrial suburb of Vancouver. The interior was stuffed with sets for the remake of the sci-fi movie classic The Day the Earth Stood Still. Fox studios had brought me here to be a technical advisor ? to review the film's script and some of the staging to ensure that this archetypical tale of aliens come to Earth was at least modestly true to science.

In the 1951 version of this story, Klaatu (played by the smoothly laconic Michael Rennie) lands his saucer on the White House ellipse. He's come to deliver a telegram to Earth, and the message is straightforward: Don't spread nuclear armaments to the rest of the Galaxy. Failure to heed this small request will provoke a fate "too terrible to risk" at the mechanical hands of Gort ? an interstellar Robocop brought along by Klaatu who looks as if he could barely stumble across a busy street. If we don't behave, Gort and his chrome-plated android buddies will reduce Earth to "a burned-out cinder." The worst kind.

Now, a half-century later, Klaatu and Gort are back ? with more complaints. No longer concerned that Earth will somehow start nuking other planets, the aliens have sent their good-cop, bad-cop emissaries to rescue terra firma from environmental destruction. Imagine: The inhabitants of other worlds are more concerned with global warming than we are (although their remediation plans are not gentle)! This intervention reminds me of alien abductions: not precisely the social life to which you aspire, but at least someone's showing interest.

My job on the film was straightforward: review the screenplay for errors in the science, and coach the principles in certain technical details.

I read the script several times, and made suggestions both with regard to the specifics of the dialogue, and the portrayal of the (earthly) scientists. The former sported some techno-babble that ? while approximately accurate ? was as stiff as an I-beam. Real scientists don't describe an object entering the solar system as "notable for the fact that it was not moving in an asteroidal ellipse ? but moving at nearly three times ten to the seventh meters per second." More likely, they would say that there was "a goddamned rock headed our way!" (Real scientists might also note, in passing, that any object encountering the dust of the inner solar system at 0.1 times the speed of light would burn up faster than a bug in a blast furnace. But that's Klaatu's problem.)

In addition to making dialogue suggestions, I tried to wean the filmmakers from the clich? image of scientists as clipboard-carrying, labcoat-wearing ciphers. Rather than addressing one another as "Dr. Rodney" or "Professor Furball," I suggested that they do what real scientists do, and use first names (or in the case of men, last names) without the honorific. Stuff like that.

Among my biggest responsibilities was to advise Jennifer Connelly on believable jargon and interests for her character Helen, the astrobiologist. Connelly was, like Reeves, remarkably serious about her role, wanting to understand her real-world counterparts as well as possible. She did everything short of writing a NASA grant application.

In Vancouver, my major task was monitoring a sequence in which Klaatu meets up with a human scientist, Professor Barnhardt, played by John Cleese. The two of them engage in a blackboard duel, writing equations to flaunt their stuff, eventually convincing Barnhardt that this Klaatu guy knows some important physics that humankind doesn't. The film's director, Scott Derrickson had me suggest some high-falutin' equations for this interchange, and instruct Reeves and Cleese on how to convincingly chalk them on the board. The equations were taken from General Relativity, and since this is hardly my specialty, I enlisted the help of a couple of experts (Marco Peloso at the University of Minnesota, and Hector Calderon and William Hiscock at Montana State) to come up with some relevant mathematics.

Actors are better at memorizing lines than tensor equations, so the formulae were first written on the board in light pencil, and Cleese and Reeves simply traced them as the Panavisions rolled. After a few takes, I told Derrickson about my concern that Keanu was scribing the Greek letters very slowly, and it might not look convincing. The director responded, "Hey, Seth, he's an alien!" Sounded right to me.

Between takes, both Reeves and Cleese solicited my opinion on subjects that had nothing to do with the film. In particular, they wanted to know why we're here. What's the grander meaning of our existence? Apparently a lot of people assume that astronomers, who deal with big things and long timescales, have some insight into what life is all about. More than, say, tax accountants.

"Surely," Cleese ventured, "we're here for a purpose." I figured that a lifetime of standing around movie and television sets, not to mention the front desk at Fawlty Towers, had prompted this question.

"Well, John," I responded, "maybe that's true. Maybe there is some grand plan. But then again, you might have asked that question 100 million years ago, hanging out with a bunch of your dinosaur pals. The answer then was 'you're just a dinosaur.' The answer today might be no more profound."

I'm not sure Cleese was fully gratified by my response.

The Day the Earth Stood Still raises a straightforward question: Should we really expect aliens to intervene in our bad behavior ? be it nuclear warfare, global warming, or any other ornery aspect of contemporary society?

I think it's unlikely. The evidence for these transgressions is now moving into space at the speed of light, betrayed by the flash from bomb tests and the atmospheric absorption features of chlorofluorocarbons. But this evidence ? even aside from being difficult to detect ? has reached only a few thousand nearby star systems. It's a very long shot indeed that Klaatu or his buddies will know about any of our problems, let alone rocket to Earth to solve them.

But in a way, that's all beside the point. The sci-fi films I so avidly devoured as a youngster weren't important because of the science content (such as it was). They were significant because they engaged me emotionally, and inspired me to learn more. In that sense, The Day the Earth Stood Still may have a greater impact on the next generation of scientists than any ten textbooks.

Seth Shostak is Senior Astronomer at the SETI Institute and host of the weekly radio program Are We Alone?.