第9章
Beyond the Horizon: Middle and Remote Futures
Looking beyond the immediate challenges of the next century, we can consider what awaits our descendants on scales of thousands or even millions of years-the "middle future." While difficult to predict with precision due to the unpredictable nature of purposeful beings like us, tantalizing hints suggest fascinating possibilities.
Our most important contribution is getting through the current bottleneck centuries while we're learning planetary management and possess Armageddon weapons but few off-Earth settlements to serve as refuges. Success would open pathways to the middle future for billions of humans and post-humans. This spectacular potential legacy gives profound meaning to our present moment.
What will planetary management require? Like all complex structures, a conscious planet will need distinctive emergent properties to survive and flourish: coordination and planning at planetary scale; advanced science and technology to solve wickedly complex problems; new educational approaches helping humans understand their collective challenges; and ethical systems motivating people to value a flourishing biosphere for their descendants and billions of other species.
Four crucial technological developments will shape our future: sustainable energy production, nanotechnology, artificial intelligence and robotics, and biological technologies that will transform human bodies into human-machine hybrids with indefinitely long lives.
The modern world was built with fossil fuels, but we now know we can't continue using them. Most promising energy technologies are essentially new ways of mining sunlight. Hydropower taps solar energy indirectly through water flows, wind power uses sun-driven air currents, while solar power mines sunlight directly through artificial photosynthesis already more efficient than natural forms.
Nanotechnology-building machines at molecular scales-promises to revolutionize our world. Biologists are developing nanobots that could enter the body, repair problems, and disassemble themselves like proteins in a cell. Eventually, machines may become invisibly small and so cheap we'll barely notice their cost in money or energy.
Artificial intelligence and robots may prove even more revolutionary than nanotechnology. The crucial question is whether we can maintain control over machines once they surpass human intelligence. Toby Ord considers a "Spartacus rebellion" by smart robots one of the likelier paths to existential catastrophe. Samuel Butler warned in 1863 that "Man will become to the machine what the horse and the dog are to man."
New medical, biological, and genetic technologies will transform not just our environment but ourselves. By the year 3000, the people we'd meet might seem as strange as their technologies and cities. With gene-editing technologies like CRISPR, we can now modify organisms gene by gene. Transhumanists welcome these developments, envisioning cybernetic, biological, and genetic transformations that enhance human capabilities, eliminate discomfort, extend lifespans indefinitely, and blend humans with machines.
Biological diversification will accelerate as humans migrate to other planets and celestial bodies. Given our species' history of exploration, our descendants will inevitably migrate into space, taking other species with them and creating new conscious planetary bodies in a reproduction-like "budding-off" process. As anthropologist Ben Finney notes, "We evolved as an exploratory, migratory animal" capable of adapting to environments through technology rather than biology.
This chapter extends beyond our lineage's future to examine Earth's, the sun's, the galaxy's, and the universe's futures, ending with speculations about the conclusion of the epic that began with the big bang 13.8 billion years ago. Surprisingly, we can sometimes see the shape of the remote future more clearly than the next few centuries, and these glimpses suggest something profound: we live at the beginning of time. Our universe is young, with most of its story still untold.
Plate tectonics are well enough understood to predict Earth's geographical configuration 100-200 million years ahead. With the Atlantic widening while the Pacific and Mediterranean shrink, the Americas will eventually meet East Asia and Australia, while North Africa and Europe will fuse together. In about 200 million years, these movements will form a new supercontinent some call "Amasia," surrounded by a vastly expanded Atlantic Ocean.
Our sun grows larger and hotter as helium accumulates in its core-it's already 10% larger and emitting 40% more energy than at birth. Life has survived this warming because greenhouse gases decreased while oxygen increased, maintaining suitable temperatures. In about a billion years, increasing solar heat will break down atmospheric carbon dioxide, causing plants to suffocate, followed by animals that depend on plant-produced oxygen.
In 3-4 billion years, an even hotter sun will boil away Earth's oceans. Radiation will split water molecules, with hydrogen escaping to space while oxygen combines with materials like iron, causing Earth to rust. When surface temperatures reach 1,000C, rocks will melt and Earth will resemble Venus as even the toughest life-forms perish.
How will it all end? This fundamental question has been asked by all human societies. There are two main possibilities: either the universe is eternal with no end, or it is finite with a definite conclusion. Since the 1960s, most cosmologists have accepted the big bang paradigm, dating the universe's beginning to about 13.8 billion years ago and speculating about its eventual end.
To grasp the scale of modern scientific eschatologies, we can use our sun's lifetime of about nine billion years as a basic unit. The universe has existed for just 1.4 solar lifetimes but is expected to last billions or trillions more. This tells us we live in a young universe, having seen only the first few lines of its story.
In 1998, two teams of astronomers discovered the universe's expansion rate wasn't slowing but accelerating and had been for several billion years. Most cosmologists now attribute this to "dark energy," a poorly understood force that increases expansion as the universe grows. This suggests the universe will expand faster and faster forever.
In this scenario, the universe grows increasingly large, cold, and empty until different regions lose contact because light can no longer bridge the distances between them. Eventually, astronomers would see only their local galaxy group, perhaps puzzled by ancient records claiming billions of galaxies existed. In this fragmented universe, even red dwarf stars will die, leaving only dead stars, black holes, and quantum debris.
Another idea that could rewrite our cosmic story is the "multiverse." Many cosmologists now seriously consider that our universe may not be alone. There are theoretical reasons (though no hard evidence) for imagining big bangs occurring continuously in a multidimensional space even larger than our block-universe. Different universes might have slightly different fundamental attributes-perhaps gravity is stronger or electromagnetism weaker. Some might last seconds, others much longer than ours.
These are fascinating ideas, but we currently have no evidence for them. Our technologies allow observation of only one universe, leaving theories about others based solely on logic and imagination. As astronomers joke when asking students to "Define the universe and give two examples," we have a sample of one. For those studying the future, this joke is painful-though we constantly imagine multiple futures, we only ever experience one.
