How could a Dyson Sphere be destroyed through natural causes?

Question

I would like to destroy a Dyson Sphere so it leaves big chunks of scrap metal with no habitable zones left, but still with enough structure to hold building-sized blocks.

The destruction shouldn't be man made.

Sphere Description (ordered from the sun to the outer layers):

1. Habitable Zone: cities, agricultural farms, places
2. Support Zone: electricity and water supply, first structure level
3. Main structure: the other structure levels where everything is built on.
4. Spaceports and Cargo System: an infrastructure on the outside where spaceships can dock and a network of "Trains" transport cargo
5. Shield Pylons: for shielding the whole Thing against little meteoroids and ships.

I've described the hull of the sphere about 200 - 500 meters thick.

What could make such an impact on the Sphere? How would the destruction progress after the initial "blow" hit the Sphere?

ETA: This question has been refocused slightly, as such some of the answers below are a little out of date.

Answer 1

A Dyson sphere is not stable on itself, for a variety of reasons.

On one side, since the sphere encircles completely the star, it does not feel the gravity, so it must be kept on place artificially. This means having rockets or jets of some kind, thus placing extra tensions on the structure.

On the other side, the sphere can feel the variations of the gravity field caused by e.g. external stars that pass nearby, so it feels tides, which are not good for a solid structure. If the sphere does not encircle all planets (think on a Dyson sphere the size of Earth's orbit, to lye in the habitable zone) external planets cause tidal forces on the structure.

Moreover, you have material fatigue. If your maintenance is not perfect (and it is hard to have perfect maintenance on a sphere with hundreds of millions of kilometers in radius - this is 10,000,000,000,000,000 square kilometers to maintain), the sphere will corrode (even if it is not metallic, there are gamma rays and free protons out there) and eventually tear apart. Moreover it is probable that the sphere fails on itself. Simply some vibration that happens to be in a normal vibration mode of the sphere (thus causing resonance) will destroy it.

And then there are cataclismic events like large asterois or comets, etc.

Answer 2

What about the sphere being hit by a cosmic string?

Some excerpts from the Wikipedia page:

Cosmic strings, if they exist, would be extremely thin with diameters of the same order of magnitude as that of a proton, i.e. ~ 1 fm, or smaller.

[...]

Even though cosmic strings are thought to be extremely thin, they would have immense density, and so would represent significant gravitational wave sources. A cosmic string about a kilometer in length may be more massive than the Earth.

[...]

The only gravitational effect of a straight cosmic string is a relative deflection of matter (or light) passing the string on opposite sides (a purely topological effect).

Also on this blog entry on how to destroy the earth you find

1. Whipped by a cosmic string

You will need: a cosmic string and a whole lotta luck

Method: Cosmic strings are hypothetical 1-dimensional defects in spacetime, left over from earlier phases of the universe, somewhat like cracks in ice. They are potentially universe-spanning objects, thinner than a proton but with unimaginable density - one Earth mass per 1600m of length! All you need to do is get a cosmic string near Earth, and it'll be torn apart, shredded, and sucked in. Probably the entire rest of the solar system would be too.

Earth's final resting place: String.

Feasibility rating: 1/10. Mind-bogglingly unlikely. Even if cosmic strings do exist, which they may not, there are probably only about ten of them left in the ENTIRE UNIVERSE. And they can't be steered, unless you have godlike powers, in which case you might as well chuck the Earth into the Sun and have done with it, so you're relying entirely on luck. This. Will. Never. Happen.

Source: this method suggested by Dan Winston.

BTW, you might also be interested in some of other entries of the latter site; after all whatever can destroy the earth should be able to do huge damage to a Dyson sphere, too.

Answer 3

I would say that a few rocks aren't going to affect a Dyson Sphere, however, a passing brown Dwarf or even a White Dwarf, could put enough pressures on the whole system to truly disrupt it's functioning, maybe even tear it apart.

The gravity between two stars would flex and bend the sphere.

Answer 4

I have several thoughts.

Let's start with your opener - meteors, firstly they will need to be travelling at very impressive velocity to breach something half a kilometer thick! It's possible but I can't help thinking someone with the technology to build a Dyson Sphere could cope with a few stray rocks.

Even damaging the outer skin in a single place would be fairly devastating to a sphere - assuming the inside is pressurised atmosphere would start to leak out dragging debris with it and causing massive damage. What about some tiny robots which worked their way through the weak spots of the superstructure?

My first thought is could someone do something to the sun itself? Having already established there must be some seriously impressive technology behind this location could the inhabitants of the sphere harvest something from the sun which causes it to react badly? Could excess mining tip it to cause a either supernova, implode into a black hole, scorch the ground with flares, throw out lethal radiation... you get the idea?

Finally physically destroying the sphere may be an option but there are more ways to get people to abandon a city other than blowing it up, there could be a sudden change of heart towards outsider or a plague, a famine. Perhaps your simplest solution is to look at real world reasons which force people to leave places. You may find these are a lot easier to explain than trying to undermine such advanced technology! Who knows, maybe the rush to escape or low maintenance will cause it's destruction in the long term.

Answer 5

Have you thought about having the meteors being like a thousand fist-sized meteors, explain it that because of the small size of each meteor they slipped past the sphere's defenses. piece by piece the meteor shower could destroy infrastructure to a point where it becomes unstable and thus requiring your party to leave.

Answer 6

An event from outside massive enough to damage the sphere or a structural failing of the sphere itself are both too prone to wreck the whole sphere, causing complete breakup of it. I thought of two things: 1) Some kind of calamity during construction that kills off or reduces capabilities of whatever being or race is building it. If the framework is already in place but not the 'land', you've got that framework you want. 2) The star changes somehow. If it grows or intensifies, the habitable area will be scorched at least, rendering it uninhabitable. If the star shrinks the habitable area will freeze over, rendering it uninhabitable.

Answer 7

Stars have a temperature difference over a long period of time. A Dyson Sphere, absorbing all of the energy from a star, would be sensitive to those changes over a period of time. This is described via the Standard Solar Model. An increase of, say, 10% could lead to a runaway climate effect on the entire sphere that isn't manageable, which could lead to it being abandoned. This will take a very long time to have a real chance of an effect.

Beyond that, it could run out of fuel, and if that happened, then it would become unstable. Eventually parts of it would run in to the Sun, and would fall in lots of pieces spread all over the place. A scenario that this could happen is described in Ringworld, where essentially due to a lack of raw materials, the civilizations gradually regress in to a pre-technology civilization, where they eventually forget to fuel the rockets keeping it stable. Maybe these rockets even get stolen. In any case, if the Dyson Sphere is neglected for any reason over a lengthy period of time, it will cause some serious environmental issues, eventually having it fall in to it's host star.

Answer 8

If the sun in the center of the Dyson Sphere went SuperNova that would destroy the Dyson Sphere. It is in some way concievable that a small proportion of the sphere might survive. With that much matter to be destroyed it may be possible to postulate that some sections would survive.

Answer 9

Kinetic energy (from meteors) doesn't simply create damage at a point of impact, it also imparts acceleration onto the impacted body. Any* motion of the sphere takes some part of it closer to it's parent star.

Not only that but the motion will accelerate, as the closer to the star a mass is the greater influence a star's gravitation has over it. Your result is that the Dyson Sphere tears itself apart before it actually 'touches'' the star because one side(part, not hemisphere) of the sphere is under greater and greater gravity-induced acceleration whilst the other side is under less and less. If it's a '3d polygon' it seems to me you have to have an immensely resilient sphere to be able to apply sufficient counterthrust without wrecking your shell.

Otherwise, you have two oppositional impacts.

Firstly a dyson sphere is of course restricting the transit of mass from interior to exterior but not restricting the gravitational impact of the star.

Under normal conditions a star acts as an attractor (gravity) and repeller (ejected massive particles)

Some learned individual I'm sure could do the math if it's at all relevant..

But it seems to me that if your Dyson Sphere is not absorbing the same 'quantity' of force and mass that it#s Star normally ejects your Star is effectively gaining mass.

And mass that would otherwise be repelled by solar wind etc et al..is now drifting inexorably towards your Sphere. It's all well and good saying "I shoot meteors with lazors" but that doesn't actually change where the mass that composed that meteor is being is being attracted to.

Intuitively, that all seems plausible to me, but even so how long (if ever) such a process would take to materially impact your structure is entirely beyond my ken.