Stephen Baxter - The Science of Avatar

Other Na’vi tree-climbing adaptations might include their bone structure, which is strengthened by a natural carbon fibre, an advantage shared by many Pandoran creatures such as the banshee. And perhaps they have better proprioception than we do. Proprioception is the sense of the position of the parts of the body—of place, movement, locomotion. Maybe that’s why the Na’vi, on the backs of their banshees, are such good natural pilots.

We glimpse the Na’vi’s closeness to their trees in one other touching detail. During his first night in Hometree, avatar-Jake sleeps with the Na’vi, curled up in a leaf-hammock high in the branches. In the background we see a family group tucked up in a single leaf-hammock. The leaf-hammock is a plant, an epiphyte, a plant not rooted in the ground but using the tree for support, while extracting nutrients from rainwater and other sources. The Na’vi call the hammock “safe in the arms of Eywa”— Eywa k’sey nivi’bri’sta . Similarly the chimps like to sleep in nests of leaves high above the ground. And, I like to think, maybe our australopithecine ancestors returned to sleep in the green comfort of the high branches, after a day in the brutal openness of the savannah.

Why should the Na’vi be so disconcertingly humanoid, and so different from the background of their own world?

Of course, looking from the outside at the Avatar universe, we can always point to creative licence. Neytiri, with her catlike features, is sufficiently human to be a sympathetic character, but with a mix of familiar-but-incongruous features to give the audience the sense of the alien. Neytiri trying to hug Jake with four arms might have looked distractingly comical!

But within the Avatar universe observers are puzzled too.

Among the hypotheses to explain the Na’vi’s human-ness are convergent evolution, as we discussed in Chapter 23; perhaps the four-limbed humanoid form is an inevitable end-point of evolution on any world. Or perhaps Na’vi and humans are actually related, through some process of interstellar panspermia, either natural or purposeful. Or, some suspect, maybe a divine hand has been at work; perhaps both we and the Na’vi are the result of a process of intelligent design—but the whole subject of the theological status of the Na’vi is fraught. As yet there is no clear answer. Maybe one of these ideas is right; maybe none is. We have much to learn about the Na’vi, and their world.

However humanoid they are, with their language, art, music, hunting prowess and artefacts, the Na’vi are clearly as intelligent as we are—if not more so, despite our more advanced technologies. And as such encountering them is a fulfilment of a very ancient dream: of finding other minds in the universe.

The idea of extraterrestrial intelligence has very deep roots in our culture.

Renaissance thinkers were astounded by Galileo’s first telescopic observation of the moons of Jupiter, a system invisible to the naked eye, yet like a miniature solar system in its own right. As the astronomer Kepler said, “Those four little moons exist for Jupiter, not for us… We deduce with the highest degree of probability that Jupiter is inhabited.”

This powerful intuition of the commonness of life has always caused great controversy, just as it does today. Saint Augustine, for example, long ago decided that aliens couldn’t exist. If they did, they would require salvation—a Christ of their own—but that would contradict the uniqueness of Christ, which is theologically unacceptable.

On the other hand there are some who believe that alien visitors have visited the Earth, and may indeed be among us now. Personally I am sceptical about the UFO narrative. I’ve no doubt that many reported sightings are based on something real and observable—odd atmospheric phenomena, sightings of secretive military projects—but I’ve seen or heard of no firm evidence of any extraterrestrial intelligence behind any reported sighting. And it’s just too hard for me to believe that creatures advanced enough to cross the stars would behave in the secretive, vindictive and downright irrational manner many reports claim…

And yet.

If we aren’t programmed by evolution to register something, maybe we simply don’t see it. There is an apocryphal story that Captain Cook encountered islanders who seemed unable to see his great ships, until the crew launched their smaller, more familiar-looking boats to row to shore. The islanders had never seen such huge structures before, and they simply did not have the conceptual equipment to take them in. Similarly, an alien artefact would be in a different category of object to anything previously encountered by a human being, neither of the natural world, nor created by a human. And if a UFO were to visit the Earth, then perhaps elusive, half-seen glimpses, wrongly interpreted in terms of familiar objects, is precisely the kind of “evidence” we should expect.

But don’t quote me on that.

Today, fully trained scientists armed with the most modern equipment are busily searching for evidence of alien minds.

2010 saw the fiftieth anniversary of Project Ozma, the first modern experiment in SETI (Search for Extraterrestrial Intelligence), when, back in 1960, American radio astronomer Frank Drake listened for alien signals from two stars at one frequency for a week. The idea came from a seminal paper published in Nature in 1959 by two physicists, Giuseppe Cocconi and Philip Morrison, who realised that the then relatively new radio telescopes could be used to send signals between the stars: “Few will deny the profound importance, practical and philosophical, which the detection of interstellar communications would have.” In the last few years I’ve become involved with SETI myself, having joined one of the SETI academic task forces, responsible for trying to imagine the consequences of a detection.

But Frank Drake heard nothing in 1960. And after fifty years, surely the most striking thing about modern SETI is that there have been no positive detections. What’s going on?

Advocates of radio-astronomy SETI point out how limited the searches have been so far; only a small number of stars in a small range of frequency domains for limited times have actually been studied. But there have also been unsuccessful searches for other sorts of evidence, such as artefacts at gravitationally stable points in the solar system. Even distant galaxies have been examined, fruitlessly, for signs of cultivation by super-intelligences, as in the Carl Sagan novel Contact and the Robert Zemeckis movie based on it.

Absence of evidence is not evidence of absence; we can’t yet conclude we are alone. Nevertheless it can’t be denied that the sky is not full of radio-noisy, close-by civilisations, as might have been hoped back in 1960.

A paradox is emerging. In Chapter 22we looked at the origin of life, and ways life could spread naturally from world to world. Life emerged on Earth about as quickly as it could. If it did so here, why not elsewhere? What’s more, our experience of Earth shows us that if life exists, it spreads wherever it can. The Galaxy is big, but old enough for life to have spread across it many times over, even if it travelled at speeds much less than that of light. So where is everybody? This is a development of a back-of-the-envelope argument first made in the 1950s by the great physicist Enrico Fermi (supposedly in the course of a long lunch). It has become known as the Fermi Paradox : if they exist, we should see them.

Possible resolutions of the Paradox have been extensively explored in science fiction, and in science. Perhaps there is some higher form of existence, as unimaginable to us as a Beethoven symphony is unimaginable to a single neuron in its composer’s brain. Or it may be that there are many species—like the dolphins, perhaps—with intelligence but without the opportunity to develop technology, because they live in an aqueous environment, or are spun out among the great rich interstellar clouds. Or maybe they simply aren’t interested. Frank Drake’s radio telescopes would not detect a trace of the Na’vi, inhabitants of the nearest star system, because they have better things to do than build radio transmitters. Or maybe most advanced technological species blow themselves up, as we’ve come close to doing, or exhaust the resources of their world, as in the “ecocide” of the Avatar future.