To me, Dyson Spheres seem impractical. For one, where are you going to find all the material needed to cover even a fraction of the surface of a star? Additionally, if you do build something that massive, you'll probably influence the movement of the planets.
The term "Dyson Swarm" is preferred because it is a cloud of orbitals, not a rigid sphere. A rigid sphere was never the idea proposed (by Freeman Dyson). This idea comes from science fiction misunderstandings of the term "Sphere".
Think of a Dyson Swarm ("Sphere") as the water droplets in a fog. Collectively they absorb the light going through but the water droplets (and the orbitals) are relatively sparse. So a billion orbitals around our Sun at a distance Venus and Mars would still have a mean distance between them of over 100,000km.
So how much material do you need? One estimate I've seen for a billion such orbitals is less than 1% of the mass of Mercury. Why Mercury? Because it's metal-rich and its proximity to the Sun means energy is incredibly abundant and cheap.
That's to build billions of O'Neil Cylinders.
Even if you don't need that much living room, here's something else you can build: statites. That's a portmanteau of "static satellite". Instead of orbiting the star, they are so light that the solar wind is sufficient to counterbalance the gravity. These things would simply collect energy and/or just reduce the amount of solar energy hitting something like a planet (eg to cool the EArth).
I don't want to say they are practical, but for sure you would build them with planetary matter so you would influence the movement of planets as you would dismantle them. At the end you would not have any planets left.
You disassemble a planet for the raw materials. Mercury would do.
The real problem is that Dyson spheres are wasteful because stellar fusion is thermodynamically inefficient. If you harvest the material of the star and fuse it yourself, you can keep the lights on for trillions of years.
Interesting thought. I've never heard of this idea. Let's think it through.
If I understood correctly, you suggest to turn the heat from fusion into a usable form of energy. On earth we'd do that using steam turbines. Harvesting only the hydrogen from the star to bring it on a planet and fuse it in a reactor seems silly, as the hydrogen is already at sufficient temperature to fuse on its own. So we could send water and steam turbines close to the sun where the turbines charge some sort of battery? Perhaps on some super elliptic orbit, where we switch the full batteries with empty batteries at the apihelion.
You can keep it in the same orbit but spread the mass out along the orbit to the other side and that changes the combined CoG to be closer to Sun's CoG in turn changing Earth's orbit, albeit probably slightly
GPT4 seems to think it is a 3 body problem. Mercury and Earth are of similar size and exert gravitational effects on each other. Take away mercury and maybe the earth slowly drifts a little.
The point is that a very small difference in starting conditions yield wildly different results.
Interestingly, all of those supposed spheres are around dwarf stars, which make them inherently more practical for two reasons:
1) Much less material required
2) Much longer star lifespan (trillions of years rather than a handful of billions)
However, what's interesting is that those spheres all seem to be around red dwarf stars, which are much more active and shorter-lived than white dwarfs. They're just not as stable.
Our nearest neighbor, Proxima Centauri, is a violently active flare star -- and it's also a red dwarf with an estimated lifespan of ~4 trillion years.
But white dwarfs -- which are technically stellar remnants -- are indefinitely stable. They just keep cooling. It's surmised that they'll still be quite a lot warmer than the universe's background temperature in 10^15 years.
This has yet to be observed, but red dwarf stars, when they reach the end of their lifespan, should contract and become white dwarfs. It's said that our sun will also eventually end up as a white dwarf.
White dwarfs are superlatively stable, long-lived, and quite hot. And there are already quite a lot of them. If you're going to build a Dyson sphere/swarm, they're a very good choice. Though red dwarfs aren't bad...
If you are on the level to think about building a Dyson sphere, you are probably also able to create solid matter from the star's energy itself and the other matter floating around the star system. At that point, it's more a question of how long it takes, then how you do it.
I don't think the article and researchers meant it's actual rigid sphere, that's just the Star Trek based popular opinion. Dyson Sphere is Dyson Swarm, people just didn't get it the first time.
it can be super thin (compared to sun scale) so you wont need lots of material, like you dont need lots of gold to plate contacts. And as there is not a lot of mass there will be not a lot of influence on gravitational field.
