In 1960, British theoretical physicist Freeman Dyson published a one-page paper in the journal Science that offered perhaps the most hopeful vision ever conceived of humanitys technological future. Dyson imagined that an advanced civilization would meet its heightened energy needs by building a sphere around a star to absorb its energy output.
The paper focused more on theory than engineering, and Dyson provided scant details on what such a megastructure might look like or how we might build one. He described his sphere only as a habitable shell encircling a star. But that was enough to captivate and inspire astrophysicists, scientists, and sci-fi writers. In some depictions, the Dyson Sphere, as it became known, appears as a massive ring encircling a star and reaching nearly to Earth. In others, the Sphere completely encases the sun, a hulking megastructure capturing every bit of that stars energy. In addition to scientific works, Dyson Spheres have appeared in novels, movies, and TV showsincluding Star Trekas a home for advanced civilizations.
Dyson himself understood the challenges of constructing such a massive structure, and he was skeptical that it might ever happen. Nonetheless, his Sphere has stirred ambitious ideas about the future of our civilization, and it continues to be offered as a solution to some of humanitys most dire dilemmas. Harnessing the total energy of our sunor any starwould solve our immediate and long-term energy crisis, but when civilization gains access to the complete energy output of a star, meeting our terrestrial energy needs is just the beginning.
With so much energy available, we could direct high-powered laser pulses toward exoplanets that we think may contain life, immeasurably expanding our chances of communicating with distant civilizations. These Dyson-powered beams could travel farther into the universe than anything currently possible, penetrating the higher-density areas of space, such as dust clouds, which decay the signals we send now.
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Alternatively, we could use that power to help reach exoplanets directly by harnessing the energy we need toas some astrophysicists postulatemanipulating the space-time continuum to shorten the trip via experiments in quantum gravity. One intriguing option relies on creating so-called Kugelblitz black holes with pure photons, which have already been theorized to power the interstellar starships of the future. By warping space-time itself, we might be able to travel faster than light or create wormholes that provide shortcuts for crossing the galaxy.
More enticing still, the near-limitless energy made available by Dyson Spheres could solve some of the most perplexing barriers to life extension. Proponents of cryogenics recognize that widespread and longer use could create energy demands that far exceed whats currently available. And in 2018, researchers Alexey Turchin and Maxim Chernyakov posed that artificial intelligence might be able to digitally reconstruct people in a simulated world using DNA and other information from the deceased. Creating simulations rich enough to satisfy a race of near immortals would require huge amounts of energynot to mention clearing the many ethical and philosophical hurdlesbut the researchers proposed that Dyson technology could deliver the needed power.
Dysons ambitious vision seems more relevant than ever today. If technology continues along its current growth curve, global energy demands could increase by 50 percent in the next 30 years, according to the U.S. Energy Information Administration. Wind, solar, and other renewable energy sources will help in the near term, but a long-term solution will require more daring engineering. Dysons Sphere could be a bold solution, but it comes with obvious physical and mechanical problems, and its not clear whether these could be solved even by a civilization many thousands of years more advanced than ours.
As a professor at the Center for Astronomy and Astrophysics at the Technical University Berlin, Ive devoted decades to understanding the possibilities related to advanced alien civilizations. Ive coauthored five books on extraterrestrial life, and my interest in this science inspired me to study Dyson Spheres as a possible form of advanced alien technology. Around a decade ago, I became intrigued by the kinds of large engineering projects an alien civilization might undertake.
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In 2010, I looked at the feasibility of building a Dyson Sphere. Working with Brooks Harrop, a former physics student of mine at Washington State University in Pullman, we found numerous problems with the common conception of a Dyson Sphere, the most important of which was the spheres risk of collapse. A rigid concentric sphere around a star would experience a gravitational pull on every point. No material known today could resist that force. Engineers might counter this with a complex thruster system that keeps the shell in place via a counteracting force, but given the enormous mass of the shellmost conceptions imagine the structure to have a radius of 93 million miles, the distance between Earth and the sunsuch a system would consume a huge fraction, if not all, of the energy collected by the shell in the first place.
But say we could overcome these problems and manage to build the sphere far into the future: How would it survive meteors, asteroids, or radiation and solar flares? An object with the mass of Halleys comet would crash into the structure with a kinetic energy of more than 1 million hydrogen Tsar bombs, the most powerful nuclear device ever detonated.
Dyson foresaw those risks and acknowledged that a shell or ring surrounding a star would not likely be feasible. But the physicist proposed a solution: A loose collection, or swarm, of objects traveling on independent orbits around a star, harvesting its energy while avoiding most of the physical and mechanical problems of a solid Dyson Sphere. The satellites could be built over time and delivered gradually to the network, increasing the swarms energy production over time.
A Dyson Swarm of about 10 million satellites could fulfill humanitys energy needs. Thats a lot, but modern satellite constellations are creating precedence for such an engineering feat. SpaceX can launch 240 Starlink communication satellites a month, and as of February 2022, it already has more than 2,000 in space. The fleet could number in the tens of thousands by its completionnot Dyson Swarm amounts by a long shot, but enough to fuel our imagination.
To overcome the challenges of Dysons original concept, Harrop and I set out to find a realistic design for its replacement, the Dyson Swarm. We called our idea Solar Wind Power Satellites (SWPS). While traditional solar panels use the energy of visible light, our satellites would harvest the electrons that make up half of the solar wind. (The other half consists of protons and alpha particles.) Fast solar wind has a velocity of ~750km/s-1making these electrons richer in energy than those in the visible light hitting a solar panel. The heart of our SWP satellite is a long metal wire pointed at the sun, which would be charged to produce a magnetic field and then direct incoming electrons into a spherical metal receiver. These electrons would produce a current, which would in turn maintain the magnetic field in the wire and create a self-sustaining system between the two.
Most of the current would remain to power an infrared laser beamed toward receiving stations on Earthinfrared is optimal due to the transparent infrared window in our atmosphere, which allows wavelengths between roughly 8 and 13 microns through without absorption. After the laser sends its electrical energy to the receiving station, the remaining electrons would fall back onto a ring-shaped sail, where incoming sunlight can excite them enough to keep the satellite in orbit around the star.
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Each SWP satellite would have a mass of about 3.7 metric tons (about three times the weight of a GPS satellite) and would provide a continuous power output of about 2 megawatts per 24-hour day, meeting roughly the energy needs of 1,000 U.S. single-family homes. A full swarm of SWP satellites could fulfill all of humanitys energy needs.
These satellites could be built with relatively simple, inexpensive materials; the major construction expense would be 950 feet of copper wire per satellite. And because they use solar wind as their energy source, these satellites would absorb a minimal amount of heat and operate at nearly 100 percent efficiency. Traditional solar cells, by contrast, are expensive to produce because they require high-purity silicon for their semiconductors, and they have a notoriously low efficiency, about 20 percent.
A few technical hurdles stand in the way of a Dyson Swarm. While SWP satellites require little maintenance, theyre not self-cleaning. If positive ions rather than electrons from the solar wind get caught in the sail, they would reduce the efficiency of the satellite and, over time, degrade the system. We also didnt solve how to maintain a steady location in space amid variations in the solar wind, or how to arrange the orbits of millions (or eventually billions) of satellites around a star. And while small-scale, power-beaming laser systems have made large strides in recent years, a system that works in space is still a challenge. Small temperature changes of less than a degree Celsius would result in large changes to the lasers wavelength and output efficiency. Keeping a constant temperature in space is a headacheits difficult to transport heat from hotter to colder bodies where there is no atmosphere. We havent solved every problem of the Dyson Swarm yet, but maybe another civilization has.
In my book The Cosmic Zoo: Complex Life on Many Worlds, coauthored with William Bains, a senior research fellow at Cardiff University, we argued that once life arises on a planetary body, it will eventually evolve to become intelligentassuming the planet stays habitable long enough. The basis of this argument is that all major transitions in the evolution of life on Earth seem to have occurred several times independently from each other, or via different biochemical pathways. That would suggest that some of the trillions of other planets in the universe could have experienced this same evolutionary process, and a subset of life forms on those planets could have evolved to become intelligent. Have they advanced enough to build a Dyson Sphere? Freeman Dyson hypothesized that if they did, we could detect it.
Traditional Dyson Spheres with a solid shell might emit waste energy in mid-infrared wavelengths, detectable by current human instruments. At least one research team has looked for such a signature. Jason Wright, a professor of astronomy and astrophysics at Penn State, and Matt Povich of California State Polytechnic Universitys Physics and Astronomy department, used data from NASAs Wide Field Infrared Survey Explorer (WISE) to search for a strong infrared signal in space, which would be expected from a Dyson Sphere. That search failed to find a Sphere, but perhaps the reason our telescopes havent seen any megastructures in space is that the aliens have come to the same conclusion we did in our paper: A gigantic, solid Dyson sphere is impractical, even for a civilization more advanced than our own.
Though we might never see our sun encased in a megastructure, or draw our energy from millions of satellites orbiting around it, the scienceand science fictioninspired by Dysons Sphere continues to animate some of our most ambitious thinking about life on this planet and beyond. That might be its most valuable contributiongiving us an ambitious target to aim for, and making way for a revolutionary discovery in the attempt.
Link:
A Dyson Sphere Could Hold they Keys to Immortality - Popular Mechanics
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