Battle: Los Angeles, Red Dawn, and Alien Invasions
By Taylor Marvin
At io9, Charlie Jane Anders has a pithy post challenging the popular end-of-the-year critical assessment that places Battle: Los Angeles in the worst movies of the year dustbin:
“Here’s the thing about Battle: Los Angeles. It’s a straight-up action movie that takes itself absolutely seriously. There’s no winking at the audience, no clever banter, no irony, and absolutely no comic relief… But if you actually take this film on its own terms, as a serious action movie about soldiers, it’s a pretty good movie.”
Earlier in the year I used the film as a jumping off point for an examination of why universal economic constraints make a hostile invasion by an alien species unlikely. Specifically, I found Battle: Los Angeles’ motivation for alien invasion especially unconvincing [mild spoiler alert] — the films’ alien antagonists mount a laughably unbelievable invasion of Earth for the planet’s liquid water. Water is one of the most common compounds in the universe and planets with liquid surface water are almost certainly widespread in the local galaxy. Frozen water is even more plentiful, even in our solar system: a good portion of Uranus and Neptune’s moon systems are made up of water ice, and it strains credibility to suppose that a species capable of interstellar travel faces an energy constraint that prevents them from melting massive quantities of outer solar system ice. A hostile alien species in search of water has plenty of available alternatives to a contested invasion of Earth, especially considering the not-inconsiderable costs of transporting water out of the Earth’s (relatively) steep gravity well.
But fantastical premise aside, I really enjoyed Battle: Los Angeles. As Anders notes, Battle: Los Angeles has more in common with Saving Private Ryan and Black Hawk Down than science fiction staples like War of the Worlds or Independence Day. At its core, the film isn’t a science fiction movie; it’s a war movie that uses aliens to depict US Marines in combat against a superior force. This is an interesting narrative, and a revealing one. A generation ago films like Red Dawn could use human adversaries to create a scenario of overwhelming enemy forces challenging sympathetic US military characters. Today, that’s less credible. While the increasing military prowess of potential adversaries like China is clearly on the road to near-peer status, even paranoid American film audiences have trouble seeing PLA forces as a threatening adversary for fictional US forces. The long delayed 2012 remake of Red Dawn, which replaced the original film’s Soviet and Latin American invaders with modern PLA occupiers, encountered a more concrete problem with Chinese invaders then military plausibility: China is a growing market for American films, and MGM’s distributors were (understandably) concerned about offending Chinese theater audiences. Red Dawn’s producers buckled, and replaced the PLA antagonists with a North Korean invasion of North America. Think about this for a moment: economic concerns forced US filmakers to turn to North Korea when in search of an existential military threat for American heroes. Remember, the DPRK is a nation of 24 million people: even if every single North Korean man, woman, and child occupied the US, there’d still be 13 Americans for every single Korean occupier — bad odds. Suddenly Battle: Los Angeles’ hastily imagined aliens don’t seem out of place in a story of infantry warfare. This says a lot about the decreasing incidence of war, and’s an encouraging anecdote — while the extremes of nuclear war and limited-scope local conflicts are persistent threats to human security, large conventional ground wars against human adversaries are becoming less common even in fiction. This doesn’t mean they’re impossible, or even significantly less likely. But it does tell us something interesting about American film audiences’ ideas of credible threats to US domestic security.
Returning to the subject of alien invasions, there’s another aspect of Battle: Los Angeles that challenges credibility. Like every alien invasion movie I can think of, the arrival of Battle’s aliens take the human protagonists completely by suprise: the alien spacecraft are detected only days before they enter the Earth’s atmosphere, and are mistaken for meteors until the moment alien warriors crawl out and begin ransacking Santa Monica.
However, most imaginable forms of an alien invasion would be likely be detectable for decades before they arrived at Earth, because most imaginable interstellar propulsion schemes are extremely difficult to keep stealthy. Any spacecraft must decelerate before it reaches its destination; because many varieties of possible interstellar spacecraft travel at significant portions of the speed of light, deceleration is a long and energetic process. Nuclear pulse propulsion or exotic fusion and antimatter rockets capable of high acceleration flight would require decades long (for most possible flight times) deceleration burns to slow from interstellar speeds as they approached the solar system. These exhaust plumes would be highly visible from Earth, and give humans years of warning of approaching visitors. Other drive systems are similarly detectable. Beamed energy propulsion (where spacecrafts accelerate on extremely high powered sustained laser beams fixed at their point of origin) would be obvious decades to centuries before the spacecraft they powered arrived, and many beam propulsion schemes utilize fusion rockets to decelerate at their destination anyway.
There are stealthier deceleration options available for sufficiently advanced aliens. A solar sail that used the momentum of reflected photos to decelerate would likely be stealthier than deceleration rockets, but would remain visible as a large, hot (1,000 K+) mirror in the infrared and visible spectrum. Magnetic scoop systems would be less visible: decelerating by impinging interstellar ions, a magnetic deceleration system would be detectable only as a large, powerful magnetic field.
In addition to the high visibility of their decelerating propulsion systems, hostile aliens approaching Earth would have to contend with the thermal emissions of their spacecraft. These infrared emissions are extremely difficult to stealth: barring exotic technologies, a spacecraft will always be a hot moving object against a cold background, making it inherently more visible than asteroids and other solar system debris.
Of course, any discussion of countering hypothetical invading alien forces involves a lot of assumptions. But in the context of Battle: Los Angeles these aren’t unjustified. Battle: Los Angeles depicts uniquely primitive alien invaders, at least compared to the alien’s science fiction invasion-genere comrades. The aliens of Battle: Los Angeles appear to use weapons with capabilities broadly similar to our own, cybernetics not far beyond that plausibility available to near-future humans, and aircraft that use broadly familiar reaction propulsion rather than more exotic lift schemes. In this technological context discounting faster than light travel, (extremely) exotic propulsion and stealth technologies is reasonable. Of course, the fictional world of Battle: Los Angeles exists in the context of its narrative: the film’s writers limited their villains’ technology to make infantry combat between Battle’s Marine heros and the alien foe believable. However, despite these narrative limitations the film’s still an interesting springboard for discussion. That’s what makes fiction interesting.