Judging from the deluge of recent movies featuring aliens of all sorts — Dr. Strange, Arrival, the upcoming Star Wars movie Rogue One — we can't help but be fascinated with these imaginary creatures.
They live deep in our collective unconscious, mirroring the good and evil we are capable of. In a real sense, the aliens are us. They reflect what we know of the world and ourselves, our expectations and fears, our hopes and despair.
But there is something else with aliens, something we rarely pause to consider. Not so much the fictional types that live on our pages or screens, but the ones that may actually exist out there, in a corner of our galaxy, or possibly in other galaxies far, far away. Once we mix in real science with the possibility of extraterrestrial life, we can learn much about our current dilemmas and, hopefully, about our survival as a species.
Let's do some quick numbers for context.
Like us, aliens (at least the ones with life forms similar to ours — carbon-based, water-dependent) would live on a planet or moon circling a star. Their survival would depend crucially on the energy output from that star, and on how that radiation interacts with their planetary or lunar atmosphere. In our case, Earth absorbs about 71 percent of the total incoming solar energy: about 23 percent by water vapor, dust and ozone in the atmosphere, and 48 percent by the surface. We get roughly 140 watts per square yard on the ground. Imagine covering the Earth's surface with 140-watt light bulbs and have them all illuminated during Christmas. Not a very smart use of resources — but beautiful, especially if seen from space.
In any case, for a planet to harbor life for a long time, it needs to be fairly stable: Its orbit can't be erratic. Its atmospheric composition can't change very quickly. Its climate must be fairly stable. It needs to receive and generate large amounts of energy. Aliens out there would need to have planets that have similar properties to these.
Our species has been here for about 200,000 years, a mere trifle compared to Earth's age of 4.5 billion years. From a cosmic perspective, we are a baby smart species, with many challenges ahead to ensure our long-term survival. This is where "they" could be useful.
The first thing to note, at least from our own history, is that odds are very small that two or more intelligent species could coexist in the same planet. (Disclaimer: There are many ways to define and quantify intelligence. I am interested in creative intelligences capable of developing advanced technologies.) Given life's implicit combative-survivalist nature, another smart species would be seen as a threat, at least early on in the evolutionary race. Case in point, the Neanderthals, even if not as bright as Homo sapiens, presumably were partly assimilated, mostly decimated, by our ancestors. Peaceful coexistence of different intelligent species that can compete on equal footing for dominance seems very difficult to achieve, unless both species (or more) have achieved very high moral standards. But by then, it would probably be too late.
We then consider lonely intelligent aliens, who would have found the physical and moral means to survive for millions of years. How would they have done that?
First, they would have realized that a predatory relation to their planet and to the other life forms in it would lead to their own demise. They would have realized quite soon that their planet, even if large and plentiful, had limited resources, and that rampant, mindless exploitation would quickly transform it into a barren land, unable to sustain them. The painful example of Easter Island is a case study for what could happen globally from an unplanned, parasitic relation to the land.
The aliens would have to have learned how to live with the planet, respecting its resources and planning carefully how to exploit them in a sustainable way.
They would have learned to maximize and optimize the energy output from their parent star, just as we are beginning to do here with a combination of solar and wind energy. If their star was not powerful enough for their needs, they would have learned how to use mirrors and other focusing technologies to increase the amount of radiation reaching their planet's surface.
These aliens would have understood the interconnectedness of all things living; they would have realized they were at the apex of the food chain and, precisely for this reason, they would have taken action to preserve the biosphere so that they could make proper use of its resources for as long as possible.
They would have realized that in order to ensure their species' longevity, they had to redefine their relationship with other living creatures.
The aliens would have realized that the only way to ensure their long-term survival was to eradicate social inequality; they would have quickly found that income disparity and cultural exploitation create social unrest and poverty, both leading causes of planetary predation. So, to make sure they survived as a whole, they would have embraced all of their population as one, sharing resources in an equitable and just way. They wouldn't eradicate competition, as they saw it as key to innovation and happiness, but they would have made sure that everyone had similar opportunities to succeed. An equitable society doesn't need to be stale. They would have understood that global change needs sacrifice from those who have more, but they would have reinterpreted sacrifice as a temporary means to mutual survival. They would have created, in the long term, a society still with some level of disparity — for their scholars understood that sameness is dystopic — but with a sound baseline built on dignity, mutual trust and respect.
The result of their global-scale project of resource-protection and social justice would be revolutionary. It would have produced a major shift in moral values, erasing the last brutal vestiges of evolutionary disparities. A new era would have dawned, based on a moral understanding of their relation to their planet and to one another. This new era would celebrate difference, while identifying the fundamental unity that connects them, all belonging to the same species, all living in the same planet, all sharing the same natural resources. These aliens would have survived for millions of years, creating new ways to enjoy life and understand one another.
We have a lot of work to do.
Marcelo Gleiser is a theoretical physicist and writer — and a professor of natural philosophy, physics and astronomy at Dartmouth College. He is the director of the Institute for Cross-Disciplinary Engagement at Dartmouth, co-founder of 13.7 and an active promoter of science to the general public. His latest book is The Simple Beauty of the Unexpected: A Natural Philosopher's Quest for Trout and the Meaning of Everything. You can keep up with Marcelo on Facebook and Twitter: @mgleiser