Hiding in a galactic forest

The Fermi paradox asks why, given the size of the universe, we have no evidence of life outside of Earth. The Remembrance of Earth's Past series presents a disturbing possibility

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Have you ever stared at the stars and thought that, given the unfathomable number of stars and planets in the universe, other life simply must exist? The number of observable galaxies ranges in the hundreds of billions. Surely we are not that special. Yet we still have no evidence of extraterrestrial life.

You aren’t the first to wonder. In fact, this has a name: the Fermi paradox.

There have been a number of attempts to reconcile the likelihood of extraterrestrial life and the absence of evidence for it. Some experts believe that intelligent life is exceedingly rare, a hypothesis called The Rare Earth Theory. Others believe that intelligent civilizations may only exist for a brief period of time, meaning that two intelligent civilizations may be nearby spatially but not temporally. Still others believe that intelligent civilizations are fairly common, but for technological or biological reasons human beings cannot perceive each other. 

The first novel in the series, The Three-Body Problem, is based in China during the Cultural Revolution. Ye Wenjie, a political dissident and astrophysicist, is recruited by the military for a secret project. It turns out that the project is to seek out extraterrestrial life. Ye is eventually contacted by an alien pacifist from the planet Trisolaris, who warns Ye not to respond again or else Earth will be invaded. As a political dissident suffering under the Cultural Revolution, Ye is disillusioned and embittered with humanity.

She responds immediately.

The Fermi paradox is the central theme of Liu Cixin’s award-winning science fiction series, Remembrance of Earth’s Past. It first appeared as a volume in a science fiction magazine in 2006, with full publication of the first book in 2008. The books were translated into English by Ken Liu in 2014.

Cixin Liu writes from a third-person narrative, which allows the reader to have consistency of perspective as the story shifts across the centuries. The translation of the first book in the series, The Three-Body Problem, from Chinese to English helped to bring it into the mainstream, and Cixin Liu himself has heaped praise onto Ken Liu’s translation. “Usually when Chinese literature gets translated to a foreign language, it tends to lose something,” he said. “I don’t think that happened with The Three-Body Problem. I think it gained something.”

One thing it gained was a massive new audience. Published in English in 2014, The Three-Body Problem won the Hugo Award the followed year, as well as praise from prominent readers including President Barack Obama, Facebook founder Mark Zuckerberg, and fantasy author George R.R. Martin. The success of the series’ English translations has allowed for new media development. Netflix acquired the rights to the books and has plans to produce a streaming series.

“Usually when Chinese literature gets translated to a foreign language, it tends to lose something. I don’t think that happened with ‘The Three-Body Problem.’ I think it gained something.”

Cixin Liu

The series’ answer to the Fermi paradox is known as dark forest theory, which posits that resources within the universe are constant, but civilizations are ubiquitous. These civilizations want to survive, to grow, to expand. At the same time the constraints of time, distance, technology, and biology make communication between civilizations almost impossible. Civilizations also make technological jumps in unexpected ways, meaning that the unassuming civilization today might become the juggernaut of tomorrow. As a result, the universe is in a constant state of war, with civilizations annihilated by others as soon as their locations become known. Hence the name dark forest—civilizations must hide from others to survive, and danger lurks around every corner. It is Liu Cixin’s answer to why we do not have any evidence of life outside of Earth.

Dark forest theory is outright fascinating to consider, when applying it to our own universe. Is the reason we haven’t encountered any alien life because they are hiding from fear of dangerous predator civilizations? Is the universe more treacherous than we believe it is? If Liu Cixin’s theory is correct, we should probably turn off everything broadcasting our existence to the rest of the universe. I would contend that humans and extraterrestrials would eventually find some way to communicate, and band together against bad actors. But if communication between aliens is truly impossible, universal resources are limited, and civilizations’ technological advances are unpredictable, some version of dark forest theory could explain why we don’t have any evidence of life beyond Earth.

The Remembrance of Earth’s Past series is a must-read for any science fiction fan. Liu Cixin’s perspective provides a new look at some of the most interesting questions in the genre.

Marcus Johnson

Marcus Johnson is a political commentator and a political science Ph.D. candidate at American University. His primary research focus is the impact of political institutions on the racial wealth gap.