What if one day we meet aliens and they turn out to be our descendants? The fact that someone outside the Earth can live sounds like science fiction. Our lives take place on this planet. For half a century of space flights, less than 600 people have visited Earth's low Earth orbit, and only 12 have studied the surface of an alien world. The cost and complexity of freeing people from the yoke of gravity is killing dreams of free space travel.
However, this must change. Entrepreneurs like Elon Musk and Jeff Bezos are developing reusable rockets that can fly people into orbit with ease. Richard Branson hopes to show that there is a viable economic model for space travel, built on leisure and tourism. Robert Bigelow wants you to be able to rest at the space station in ten years. Meanwhile, governments and space agencies are stepping up their efforts to get researchers to the Moon and Mars. NASA plans to deliver astronauts to Mars by 2035, and China intends to have an orbiting space station and a lunar colony at the same time.
These plans are fueled by technological innovation. New materials will allow rockets to be lighter, stronger, and cheaper to launch. The parts will be 3D printed on the International Space Station. The moon and Mars are far away, but their soil is quite easy to turn into building materials and get water for drinking and oxygen for breathing.
It is even possible to build a space elevator to the moon: a heavy-duty cable that extends into the sky, supported by its own weight and the rotation of the moon, that will allow materials to be transported in elevators in zero gravity. The space elevator could spur new economic activity and further exploration of the solar system. Perhaps the brave crew will go into suspended animation and go to explore interstellar space in search of habitable worlds.
Let's assume all of this unfolds over the next 50 years. We can imagine the first child to be born outside the Earth, and this event will be akin to the exit of our distant ancestors from Africa 60,000 years ago. How will life outside of Earth change us?
Several astronauts have spent more than a year in microgravity and have experienced loss of muscle mass, fragility of bones and vision problems. The space station could rotate to solve these problems, and for the colonists of the Moon and Mars, gravity will be reduced, but not zero. Their capillaries and cardiovascular systems will adjust and their muscle mass will be kept at a level.
Few of us would enjoy isolation in cramped bubble dwellings far from home. Lack of a diverse natural environment is likely to lead to a weakened immune system. However, colonists will be able to experiment with exercise and sex. Their spacesuits will be made of materials that are durable, pleasant and close to the body, so they can both live in them and explore the surfaces of new worlds.
In a fundamentally different and controlled space environment, speciation can occur much faster than on Earth.
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If the first colonies are replenished with recruits from Earth, the physiological changes will be more modest. But subsequent waves of colonists may sever the umbilical cord; they can dissent or follow utopian ideals. In life and death outside the Earth, the psychological landscape can be shaped by the worldview of another world. Biologically, they will also develop into a new branch of the human tree of life.
How long will it take and what will they be like when they stop being “us”?
The minimum viable colony size to avoid excessive genetic abnormalities and inbreeding is in the order of 160 individuals. Colonists will be subject to two phenomena that are well known among small isolated populations on Earth: founder influence and genetic drift. A decrease in the genetic pool has the contradictory property of accelerating evolution. It will also receive acceleration due to the high level of mutations, since cosmic rays will not be held back by the thin atmosphere. Small genetic diversity will be unable to contain the pressure of new speciation. Colonists can be vulnerable to new pathogens that can kill them.
Obviously, all this can lead to the fact that they have to take their own destiny into their own hands. DNA engineering and “editing” technologies are rapidly evolving, so colonists optimize their genetic makeup, bypassing the Darwinian mechanism of natural selection. Advanced medical technology and an optimized diet ensure that nearly everyone lives to their old age, not just the strongest.
Extraterrestrial colonists may not be citizens of any country, so they will establish their own legal and ethical standards. Most likely, they will aggressively adopt technology to radically improve their lives or replace body parts with mechanical equivalents. The prospect of human and machine merging is a grim prospect for many of us, but the adoption of such technology will allow colonists to circumvent many of the physical limitations. This, in turn, will expand the list of "habitable" extraterrestrial environments for colonization. The end result of such a scenario may be loading consciousness into a computer and getting rid of all dependencies of the physical body.
Some populations in Australia and Papua New Guinea have been isolated from Europeans for 30,000 years but have not evolved into new species. In an extremely different and controlled space environment, speciation can proceed much faster than on Earth.
Suppose some colonists return to Earth after thousands of years and hundreds of generations. Their language is incomprehensible, their culture is unrecognizable. They are tall and thin, with pale skin, small teeth, and no body hair. Surely we will be scared to look at them and try to recognize us in them, as if in some kind of distorted mirror.
Ilya Khel