What is a realistic based Situation in which a Dyson Sphere could be created?

Question

I felt inspired, and I wanted to write about the future of our lives.

Setting: If one had to guess, what year would we most likely be able to build a super-structure like a Dyson-Sphere around the sun?

The Setting Im trying to point out is somewhere after 2500, but any year after that time would function perfectly for what Im writing.

For the un-knowing: A Dyson Sphere is a Mega-Structure that can be created as a large orbital object created for Eco-setting and Energy Purposes, I've also heard of concepts of using a Dyson-Sphere to transport planets.

What I'm asking for, is what, when, and where could there be a situation where we as humans are able to create a Dyson Mega-Structure around the sun to Catalyze and Collect the Energy of a Cosmic Fission/Fusion Device to keep Humanity Alive for millions of years to come.

Im going to be facing a Situation where humans are living in a sort of... "Perfect Utopia" of Infinite Happiness and Perfection, but there is a looming threat... something un-natural, something fictional and magical, but real, balanced, and dangerous.

There are two main forces in the story, Humans, and the "Creatures" that wish to punish humans for killing the world, and for killing the Universe with their Greed.

If anyone could give me ideas towards these subjects, I'm all ears

Answer 1

What I'm asking for, is what, when, and where could there be a situation where we as humans are able to create a Dyson Mega-Structure around the sun to Catalyze and Collect the Energy of a Cosmic Fission/Fusion Device to keep Humanity Alive for millions of years to come.

Let's assume the mega structure is in fact a swarm, since that is both more feasible and easier to achieve than a solid sphere. Others have pointed hat out, so i won't go into detail.
Let's also use the therm "the energy of a [sun]" rather loosely, in the sense of "quite some of it's energy".
And let's also talk about the human race rather than humanity, because the latter might be a tricky subject, and subject to interpretation, which will change over the centuries.

Starting with the where part of your question, i would suggest Sol, our sun, for the boring but practical reason that it is the one we are already fairly close to. Or, in other words, because it is there.

For the when part: You are writing the story, so it is entirely up to you. You already specified 2500ad as a minimum, and i think that might actually work. But since you are writing science fiction, and you are writing about a space faring civilization, the concept of an earth year might not be the best way to measure time.
So if you take a different measure, not only will you appease those readers who doubt that the achievements in your story are feasible within that time frame, you also make concessions to the inhabitants of mars and the asteroid belt, who were never very happy with an earth year that just provided random fractions of their perceived seasons. That also got you re-elected and ended a lot of grumbling, so let's just go with that.
Or, in other words: just bypass the question, and where necessary, drop a hint or two about the time that must have passed, but stay vague.

So, finally, on to the interesting bit, the what of your question. While it might be conceivable that a civilisation (or a subset thereof) actually came up with the plan of building a dyson sphere, or swarm, from scratch, there is a different route that is easier, cheaper, requires both less imagination and less boldness, which in my opinion makes it more likely. It also saves you from endless mind-numbingly boring planning meetings. And you can bypass the war over the desired colour of the thing.
I'm talking about evolution, about venturing forth into the adjacent possible, and of becomings.
The first solar cell equipped space vehicle has been launched in the year 1958 (Vanguard 1), so if you stretch terminology a bit, that was the start of the building of a dyson swarm. Okay, you're stretching it a lot, but anyway.
The important bit is: You can get to a dyson swarm by building individual spacecraft that utilize solar energy, and you don't need to have a dyson swarm in mind at any time of the process. You just build your ship, or satellite.
Later, you build a second one. Or someone else does. After that, some more. Sooner or later, you will have quite a lot of those beasties in space. It won't be long before the desire arises to travel from one to the other, to exchange materials, for redundancy, safety, or to fight boredom.
And the more ships you have in space, the more natural it will become to add some extra.

And after a century, or a few of them (for any possible value of "a few") there will be so many objects in space, utlizing solar energy, that someone might look at a map, and say:

Oh my... where did that Dyson Swarm come from?

Answer 2

This information cannot be guessed.

There are some problems that we know we can find solution to, given enough time. There are some problems that we already have solution too, they just take too long. However, a Dyson sphere is the concept of building a device around the sun to trap and contain all the energy within it. ALL the energy of a Sun is a lot of energy, and right now we don't have the means or materials to create something like that. We don't have materials strong enough to be able to withstand the heat of the sun to encase it (that's 3.86 x 10^26 watts of energy!) and even if we could, hypothetically, get a hold of such material, we'd need to build it around the Sun, which is massive. The amount of raw material we'd need would be similar, and we'd need to expend time and energy to get it all into place without it crashing into the Sun from the orbit path it needed to get there.

All in all, it's a great concept for science fiction, but in reality, we don't know of any way to do it. Maybe we can figure it out in a 100 years. Maybe a 1000. Maybe even 10,000 - the future is unknown. But right now, we just don't know.

Answer 3

Realistically, a Dyson Sphere would be unlikely to start deliberately, unless everyone decided they really, really want to do surgery on the Sun. More likely would be a swarm composed of co-orbiting habitats and satellites, which would slowly grow to envelope the Sun.

While there are a variety of uses for building the smaller structures that will eventually comprise the swarm, it's hard to imagine why they would reach such huge numbers. You can supply the Earth's energy needs with a fleet of power satellites that would hardly leave a speck on the surface area \$pickAnOrbit, even at abismally low efficiencies. If humanity collectively decides to turn Earth into a nature preserve, or to evacuate, or something, the amount of habitats necessary to house all of humanity would likewise take up very little space, even if people want to spread out for privacy / security / isolationism, and use the intervening space for solar farms and factories. Immense transit systems could be built to make spaceflight, resource extraction, or cargo shipment more affordable, but even if you somewhy scaled this up to the Solar System rather than a handful of planets, moons, and asteroids, it'd still look like a few mega rings.

What you're looking at with a Dyson Swarm / Sphere is a civilization bigger than more or less all the galaxy-spanning civilizations in Science Fiction combined, give or take the odd outlier with poor publicity. The only way I can see such a megastructure showing up in under a millennium (which feels optimistic) is if either there is some threat for which harnessing all that power is necessary (moving the sun, turning it into a Death Star, its lifetime is shorter than we thought and we must remove excess stellar matter ASAP), or a combination of huge population growth and a boom in the popularity of insanely inefficient ventures, like interstellar colonization or a Virtual Reality MMO whose computation needs are best expressed in scientific notation.

I can imagine reasons that some civilization would Dyson up their star, but humanity as we know it seems nowhere near operating in those ways. Perhaps, if some cabal of extremely powerful people get obsessed with the idea, they could get it started, but the costs, people, and time involved mean it would almost certainly not get far without said cabal also being immortal, or run by an AI told to solve energy.

So the best I can offer is a combination of all of the above: someone unlocks the secrets to making space colonization immediately and obviously beneficial to everyone. Populations start growing rapidly again, space-based factories become essential due to the chemicals, medicines, materials, etc that can only be affordably produced there, and some overpowered ideologues somehow push through a project that grows exponentially. Bonus points for environmental shenanigans, requiring loads of space-based infrastructure to save the Earth / humanity, and it somehow works out perfectly enough to maintain growth for centuries. Maybe have some scary astronomical event (which may or may not have been misidentified or misconstrued by the popular media) to encourage Solar Security. Maybe factional disputes among those in space result in them building more and more infrastructure. And as fancy adventures become more affordable, they become more popular, and more costly.

All of that combined still feels like a megastretch. We're talking disassembling lots of asteroids and Mercury over many, many generations. Trying to think of anything remotely comparable in history, the best I've got is the Great Wall of China, and a Dyson Sphere would be so far beyond every historical megalith combined by orders of magnitude. If every human who ever lived rebuilt every structure ever built, that might scratch a sliver of Earth's orbit, which would be the tiniest fraction of a percent of a Dyson Sphere.

Answer 4

A Dyson sphere with a thickness of 10m has a volume of about 650 Earth volumes. So to build it you need far more rocky material than exists in the solar system. Because a Dyson sphere is a very thin shell rather than a massive body, you will need to provide artificial gravity by rotating the sphere. In order to provide 1 earth gravity (at its equator) with a Dyson sphere at 1AU from its star it will need to rotate about its star with a period of 88 days. Given the thinness of the shell it is impossible for such a structure to remain spherical, it will become a flattened ovoid with the polar parts being drawn much closer in to the star, therefore much hotter, and still with low gravity (going to zero at the poles). This of course assumes you have some unobtainium with sufficient strength to prevent it simply being ripped apart by the stress exerted by rotating it so fast. The best case is you would have a habitable "ringworld" around the equator of your Dyson structure with large uninhabitable energy collection regions away from the equator.

A more practical (and I'm using the word "practical" loosely!) arrangement would be a literal ringworld: such an object 1000km wide and 100m thick would only require 9% of the mass of Earth, so it could be built by cannibalising Mars or Venus (assuming you could convert the mass of those planets into sufficiently strong unobtainium to cope with the vast circumferential stress of rotating so fast). Assembling all the parts in orbit would be somewhat problematic, too. Such an arrangement would by no means collect all the energy of the sun but it would provide 47 billion times the area of the surface of the Earth, so plenty of room for population expansion. Perhaps further out than the ringworld you could have a swarm of solar collector satellites, but to block out a significant fraction of the light of the star they would again require such a large volume of raw materials that harvesting them from a very large number of other star systems would be required.

It's no wonder that your creatures think humans are destroying the universe!