In the movie Battleship, which docks in theaters today, the aliens have landed. They’re big. They’re armed. And they’re angry. Luckily, Earth has some bold (and beautiful) protectors, in the forms of Taylor Kitsch, Alexander Skarsgård, Rihanna, and Brooklyn Decker. Though inspired by the classic military strategy board game, this Battleship is pure alien-invasion sci-fi. So we sat down with Seth Shostak, the SETI scientist who advised the filmmakers, to hear him explain the science behind the science fiction.
Q: So, what do you do at SETI?
My title is senior astronomer. Doing experiments trying to eavesdrop on E.T., just as was done in the movie Contact. The idea is to determine that there’s someone out there at least as clever as we are by picking up either radio signals or light signals that they’ve either deliberately sent our way or have just leaped off their planet.
Q: The scientists in Battleship are working off the idea that there are “Goldilocks” planets that are “just right” for hosting life. Is that a real theory?
Yeah, that is a legitimate, well-used term in the field. If you find a planet around another star, one of the first questions you’re going to ask is, could it have life? And that’s very hard to know because these planets are very far away and they’re very tiny, very dim. It’s hard to get a picture of these things.
But we can tell how bright their sun is, and we know how far that planet is away from that sun, so that allows you to make a simple calculation to figure out what’s the daytime temperature on that planet. You can figure out that planet is so close to its sun that it’s going to be 500 degrees everyday, in which case there’s probably not much life because all the oceans boil away, and so do the aliens. Or you could say that planet is so far away from its star that it’s going to be minus-200 degrees day and night, so again no liquid oceans, and the atmosphere is just going to be piled up with snow. So between those two extremes, there would be some planets where you say this porridge is not too hot, not too cold. It’s in the Goldilocks zone. It’s in the inhabitable zone. Great for bears and maybe for aliens.
Q: So in Battleship the scientists try to reach these planets by broadcasting signals into space. Are we really doing that?
We don’t do too much broadcasting, but there was a very powerful signal sent in 1974 from the big antenna in Puerto Rico. It was just a demonstration for three minutes. It was sent to a bunch of stars. Now, those stars are 25,000 light years away, so it will take 25,000 years to get there. So there’s no immediate reason to be concerned.
But every night, everyday, our television stations and the radar sets at the airport are broadcasting into space willy-nilly, so in some sense, Earth is lighting up with all this traffic, but in a deliberate sense, not so much.
Q: There’s a prediction in the film that if a broadcast reached aliens, and they responded, it would be like Columbus and the Indians—except that we’d be the Indians. Is that a common perception?
There are people who have that point of view, and that quote is almost word-for-word from Stephen Hawking. If anybody came here, that could be true, because you usually meet the aggressive guys. You don’t meet the ones that are sitting at home playing backgammon. That’s the history of human exploration in any case.
Q: What are the most common questions you get from writers and directors?
They mostly want to beef up the authenticity by having you supply a plot device that they’re looking for. For example, a spacecraft has to be out of touch with homebase for a period of hours so something terrible can happen, and they need an excuse for that. What would make it possible for a ship to be out of touch? Or what would the aliens want if they came to Earth? What would lure them to our planet? That was one of the questions for Battleship. What is it that’s motivating their visit? Are they on a galaxy rock-n-roll band tour? Do they want the water? Do they want to use of for breeding experiments? What is it?
Q: What did you tell them?
I pointed out to them that water was probably not what they wanted because there’s water throughout the cosmos and besides, water is very heavy and it’s expensive to take it away from Earth. As far as I know the film doesn’t make clear why they’re here. It makes clear what attracted them, but it doesn’t explain what they want.
The only thing that’s special about Earth is the biota. You know, little E.T. came as a botanist, as somebody pointed out to me. Or they come for the culture, because the culture really is special. In one of the Indiana Jones films, that’s what they wanted, because that’s special to this planet. Our rock-n-roll is going to be different from everybody else’s rock-n-roll.
Q: What’s the appeal for you in advising movies and TV shows?
When people ask me why did I get interested in science, I always say it was the movies. When I was a kid I went to a lot of cheesy sci-fi films. Hollywood was going through this cycle of creature films and sci-fi films—They Came From Outer Space, The War of the Worlds, Forbidden Planet, The Day the Earth Stood Still. And I went to them every weekend.
I feel that if I can give the moviemakers some ideas that are useful, not just in a technical sense, but useful for showing kids how much fun science is, well, if it worked for me, it could work for them as well.