Table of Contents
- What is a Dyson sphere?
- Why would anyone construct such a bizzare monstrosity?
- Concept of the Dyson Sphere
- Do Dyson spheres exist?
Since the rapid evolution of technology, the needs for a perfect energy supply rose higher than ever, besides nuclear power plants, hopefully fusion power plants, coal plants and others… There exists a concept, a futuristic idea of the perfect energy supply that would mark the era of Human technology at its peak. In today’s topic we are going to talk about the famous Sci-fi concept of a Dyson Sphere.
We are asking ourselves a question. could we harness all the sun’s energy? The idea of the famous physician Freeman J. Dyson was first proposed in his two-page paper in the journal Science in 1960.
What is a Dyson sphere?
A Dyson sphere is a hypothetical megastructure that completely encompasses a star and captures a large percentage of its solar power output.
The concept is a thought experiment that attempts to explain how a spacefaring civilization would meet its energy requirements once those requirements exceed what can be generated from the home planet’s resources alone.
Because only a tiny fraction of a star’s energy emissions reaches the surface of any orbiting planet, building structures encircling a star would enable a civilization to harvest far more energy.
Why would anyone construct such a bizzare monstrosity?
According to Freeman Dyson, an intelligent alien species might consider the undertaking after getting evolved on that level where their needs for energy surpass the opportunities that their home planet offers.
If Human civilization expanded its energy demands long enough, there would come a time when it would demand more energy output from the Sun, and eventually, all of it. And that system of orbiting structures, or the one Megastructure would be designed to harness more of the energy produced by the Sun.
By building structures at twice the Earth-sun distance the material would be sufficient to construct a huge number of orbiting platforms 6 to 10 feet (2 to 3 meters) thick, allowing the aliens to live on their star-facing surface.
“A shell of this thickness could be made comfortably habitable, and could contain all the machinery required for exploiting the solar radiation falling onto it from the inside,” Dyson wrote.
But after absorbing and exploiting the solar energy, the structure would eventually have to reradiate the energy or else it would build up, causing the sphere to eventually melt, according to Dyson. This means that, to a distant observer, the light of a star wrapped in a Dyson sphere might appear dimmed or even entirely darkened — depending on how dense the orbiting platforms were.
Concept of the Dyson Sphere
Inspired by the 1937 science fiction novel Star Maker, by Olaf Stapledon, the physicist and mathematician Freeman Dyson conducted the thought experiment for the Dyson Sphere.
It’s important to note that although this megastructure is theoretically possible, building a real and stable Dyson Sphere system is currently far beyond humanity’s engineering talents.
The number of crafts required to obtain, transmit and maintain a complete Dyson sphere exceeds present-day industrial and engineering capabilities.
The original concept of the Dyson sphere consists of a hollow sphere or matter around a star. Since a solid shell or ring surrounding a star is mechanically impossible. The idea has given birth to three variants of this megastructure, each of them consisting of different size and design. The three concepts are:
The closest variant to Dyson’s original concept, It is composed of a large number of independent constructs, comprised of solar power satellites and space habitats(space permanent settlement).
They would orbit in dense formation around the star. This construction approach has advantages: components could be sized appropriately and various forms of wireless energy transfer could be used to transfer energy between swarm components and the planet.
One of the problems humans would stumble on is the nature of orbital mechanics, the trajectory and arrangement of the orbits of the swarm would be extremely complex. The simplest and best example of this variant is the Dyson Ring (all the structures share the same orbit, which resembles to an actual ring around the star).
More complex patterns with more rings would intercept more of the star’s output, but would result in some constructs eclipsing others periodically when their orbits overlap.
Another variant of Dyson Sphere is the Dyson Bubble. Similar to the Dyson swarm, it is constructed out of many independent constructs and likewise could be constructed incrementally.
Unlike the Dyson swarm, the objects would not orbit around the star, but would be satellites suspended by use of enormous light sails using radiation pressure to counteract the star’s pull of gravity.
Those objects would not be in danger of colliding with one another, they would be totally stationary with regard to the star, and totally independent of one another. Their distance would vary from the central star. The practicality of this approach is questionable with modern material science, but cannot yet be ruled out.
A 100% reflective satellite deployed around the Sun would have an overall density of 0.78 grams per square meter of sail.
That kind of material has not yet been produced in the form of a working light sail. The closest material that is currently produced has a density (without payload) of 3 grams per square meter. That’s four times as heavy as would be required to construct this megastructure. The construction of such a megastructure, and making it habitable would be a gigantic and merely impossible.
The required material science is far behind the required stadium, its only in the early stages of development, and besides the material science question, there are other engineering problems that need to be solved before we even think about building.
At the end of the day, if you could put enough satellites around the star, such a system would not suffer from drawbacks of massive compressive – pressure, it would have the same and thermal properties as the rigid form.
A third variant of the Dyson sphere is the so-called Dyson shell. It represents a uniform solid shell of matter around the star. With this build, this megastructure would completely alter the emissions of the central star, and would intercept(absorb) 100% of the star’s energy output.
Such a structure would also provide an immense surface that could be used for habitation. This concept and design is the only variant that could use the maximum possible energy captured from the Sun.
Non-shell designs cant intercept this much amount of energy. The biggest problem with this concept is gravitational energy, there is a possibility that if the movements went uncorrected, they could result in the collision of the Megastructure and the Star itself.
That brings us to the conclusion that those structures would need some kind of propulsion system to counteract any drift or unwanted movement so it wouldn’t collide with the star.
If choosing to construct this object, its immense size would need to be 1 Astronomical unit (149,597,870.7 kilometers or 92,955,807.3 miles). That would mean that the material forming this kind of sphere would have to be immense to prevent implosion due to the star’s gravity. For now, no known or theorized material is strong enough to withstand this pressure, and form a static sphere around a star.
It represents the only concept that could absorb 100% of the stars energy, but it is also the most engineering and material science demanding version of a Dyson Sphere.
Besides being the least possible variant to be construct, it would be vulnerable to impacts from all sorts of interstellar bodies like comets and meteoroids.
You can build your own Dyson sphere in this great game: https://store.steampowered.com/app/1366540/Dyson_Sphere_Program/
Do Dyson spheres exist?
In 2015, an astronomer Tabetha Boyajian reported the mysterious dimming of light from a star called KIC 8462852. That irregular flickering of light looked like nothing scientists had ever seen before. The unusual light fluctuations of the star were including up to a 22% dimming in brightness.
Unfortunately, those campaigns to look for signs of alien technological activity on that entity have turned up empty. The star that came to be known as Tabby’s Star (in honor of Tabetha Boyajian) was in the end a normal star, but the dimming and flickering observed has still not been fully explained today.
Even if we didn’t stumble upon evidence that these megastructures exist, we still hope that someday, with the advancement of our space exploration technology we will find one.
One of the most sophisticated engineering marvels today, known as the James Webb Telescope may detect and reveal the existence of a Dyson sphere.
To give you some insights on what capabilities a Sci-fi megastructure like the Dyson Sphere has, we will present you some facts about the power usage and absorption.
A Dyson sphere with approximately 25% efficiency would produce:
Global electricity consumption in 2019 was 22,848 terawatt-hour (TWh). Which means that a Dyson sphere with 25% efficiency would produce about one million years of electricity every second.
One interesting example is also, the largest nuclear bomb ever detonated, the Tsar Bomb, released about 210 petajoules of energy. That means that a Dyson sphere would produce 476 million Tsar Bombs worth of energy every second. The immense power and capabilities of a Dyson sphere are not imaginable, it represents the best concept for the ultimate and unlimited energy supply for a Type 2 civilization. It is on us now, only to hope that humanity will someday become that much technologically advanced, that a construction of this megastructure would be possible.
A great video where the concept of the Dyson sphere is explained: https://www.youtube.com/watch?v=pP44EPBMb8A