There was a time when Patrick Macnee made the hairs on the back of my neck stand up with the words “There are those who believe that life here...began out there. Far across the universe with tribes of humans...” This snippet of the opening narration to the 1978 Battlestar Galactica mini-series establishes right off the bat that the humans you’re seeing on the show are also aliens. Some of the earliest promotional material for Star Wars also presented extraterrestrial humans by challenging the viewers to imagine that “somewhere in space this may all be happening right now.”
Recently, with this summer’s much derided Alien prequel—Prometheus—we’re once again faced with the notion that not only are we not alone in the universe, but that we all came from outer space. What about this notion is so appealing? And just how feasible is it?
As a teenager, the first science fiction story I ever wrote (on the pages of a spiral notebook) dealt with a mad scientist going back in time to create human life on Earth by making sure the dinosaurs died and outer space proto-humans landed and started evolving. When a manager at the bookstore I worked at read the story he promptly informed me how unoriginal the concept was. The idea of human life coming from outer space might not be as old as outer space, but it’s close.
The current edition of the Encyclopedia of Science Fiction roughly defines this phenomenon as panspermia, which, despite how it sounds, is not an unreleased Nirvana album. Instead, the definition of panspermia is:
“…the speculative notion that life may spread around the universe via drifting seeds or spore that provide the starting-point for evolution on planets. The concept is ancient, dating back to Anaxagoras (circa 500 BC-428 BC) but was revived by such scientists as Hermann von Helmholtz…” (From the SFE)
Now, floating spores or extraterrestrials actually specifically causing our existence on Earth is somewhat different. But it is notable that the idea of non-terrestrial evolution (not just human evolution) crops up in actual science and myth as a well as science fiction. For SF writers, the idea of a universal humanoid code is a fairly straightforward mechanism for explaining why the majority of the aliens encountered have arms, legs, and a head.
Star Trek has gone to this well a couple of times. In “Return to Tomorrow” Sargon’s ancient species claims to have colonized several planets some 600,000 years prior to the episode. Sargon even claims to have inspired the Adam and Eve myth on Earth (even if the math doesn’t really add up.) Then, classic Trek gave us the Preservers in “The Paradise Syndrome,” who weren’t necessarily responsible for humanoid life, but rescued certain aspects of it. Later on, in The Next Generation episode “The Chase” a message from an ancient humanoid species is discovered which reveals that nearly all the “alien” races in Star Trek share the same basic genetic code with this original “humanoid.” Whether this humanoid, Sargon, and the Preservers were all the same race, it’s very clear that in Star Trek the idea of indigenous evolution is pretty much thrown out the airlock.
While old school Battlestar Galactica was vague-ish about connections between the 12 Colonies and Earth, contemporary BSG outright claims Earth human beings are actually descended from a combination of Kobol-descended humans and organic Cylons. Helo and Sharon’s human/cylon baby Hera was supposedly Mitochondrial Eve. In October of 2010, Wired ran a great excerpt from a book called The Science of Battlestar Galactica that addresses the differences between our Most Recent Common Ancestor (MRCA) and Mitochondrial Eve. From the text by Patrick Di Justo:
It’s important to emphasize that Mitochondrial Eve and her contemporaries had offspring, and those offspring had other offspring. But throughout the subsequent generations, for one reason or another, the lineages of Eve’s contemporaries all died out. Of all the women alive then (and in our case, that means the entire female population of Galactica and the fleet), only one has offspring alive today. We know her as Hera Agathon.
This does not necessarily mean that Hera is our Most Recent Common Ancestor (MRCA). Hera populated today’s Earth solely through her daughters and daughters’ daughters. The MRCA is the person who, while no doubt descended from Hera, populated today’s Earth via their daughters and/or sons. By adding males to the mix, the MRCA almost certainly cannot be the same as Mitochondrial Eve. In fact, most researchers today feel that the MRCA lived only about five thousand years ago, 145,000 years after Hera.
So, like Sargon’s math on when he and his race of humanoids inspired the Adam and Eve myth on Earth, it seems Six and Baltar’s assessment of who or what Hera was in the evolutionary chain is a little muddled. Further, Di Justo goes on to say that at some point earlier on the show, President Roslin’s cancer cells go into remission because of blood transfusions from a Cylon. If that Cylon DNA got incorporated into our humans then why did cancer pop back up again? Did Roslin have a form of space cancer? None of this renders what BSG did with the concept of human evolution coming from space totally impossible (new cancer strains could have developed, Baltar and Six were confused about the differences between MRCA and Mitochondrial Eve) but it’s not exactly airtight.
Now, science fiction isn't required to be perfect in terms of scientific accuracy or possibility—that's why there's the “fiction” half of the term. Prometheus drew similar complaints about DNA compatibility between humans and the alien Engineers who supposedly created all life on Earth. Phil Plait of Bad Astronomy recently pointed out the problems with Dr. Elizabeth Shaw’s smoking gun “proving” that the Engineers and humans are totally related. From Plait’s article:
“In a key scene, scientist Elizabeth Shaw compares a sample of Engineer tissue to human DNA, exclaiming that it's a 100 percent match. The thing is, if you compared two humans' DNA you wouldn't get a 100 percent match! That only happens with identical twins. There are lots of DNA variations between humans, so a 100 percent match is literally impossible. And last I looked, we're not 8-foot-tall bald translucent bodybuilders with anger management issues.
It's possible that she wasn't checking the whole genome, just key gene sequences. Even then it's hard to buy; chimps match our DNA to roughly 98 percent (depending on what you're measuring), so a 100 percent match even on genetic ”landmarks“ is a big stretch with aliens so different from us.”
Now, again, is the point of Prometheus to make us believe that the Engineers are real, that “out there in space this may all be happening right now?”—or as old school BSG put it, “there may yet be brothers of man who even now fight for survival”? Does it matter if it makes sense?
In Again, Dangerous Visions, Kurt Vonnegut published a story called “The Big Space Fuck” in which the population of Earth is totally aware of its impending demise, and as a result constructs a rocket full of human semen, which they plan on shooting at the galaxy of Andromeda in an attempt to repopulate the species. The battle cry for this insane plot is “Fuck you, Andromeda!” Now, I don’t need a scientist to tell me how it's absurd to think a rocket filled with human semen could actually cause humans to be born in another galaxy. From a realistic standpoint it's silly, but is it all that different conceptually to Prometheus or Battlestar Galactica? In a sense weren’t the Engineers saying “Fuck you, Earth!” and the people from Kobol saying “Fuck you, Caprica!” and the Capricans saying…well, you get it.
The idea that aliens could be our ancestors (instead of gods or supernatural deities) opens up new avenues of faith for skeptics with a science-based worldview. Instead of being made from mud, or springing from the head of Zeus, we can look up to the stars and say, “well, it probably was on one of those things, where everything else came from.” The jury seems to still be out on the scientific plausibility of all of this, but the staggering idea that it could be true continues to feel original despite its age. If actual aliens were to show up and give all of the planet unequivocal scientific proof that we are not originally from Earth, it would be beyond huge. Would the world unite like in Star Trek? Be torn apart? Would all faiths be questioned?
Those are the big questions, but regardless of the answers, I find this idea to be a source of comfort, when all is said is done, and the value of this enduring sci-fi notion that aliens made us all lies in the fact that it is comforting, in a Big Picture way. As BSG told us “this will all happen before and will all happen again.”
And if that means humans will pop up on other planets after this one is long gone, well, it’s a nice thought.
Ryan Britt is the staff writer for Tor.com.