A Simulated Stable Planetary System with 416 Planets in the Habitable Zone
nautil.us
nautil.us
If we mine the asteroids, Mars, and Mercury for materials we can build habitable surface areas that are in aggregate many times greater than Earth in size. Each carbon fiber Bishop Ring could have an internal surface area the size of India.
This simulation reminds us that space is really, really big, and really, really empty. If you can fit 416 planets, just think how many space stations you can fit.
There might be small adjustments that need to be made where Earth's atmosphere is almost completely negligible but there are fewer forces degrading the orbit and there's no immediate threat of crashing into a planet if the adjustments aren't made in time.
pretty sure the answer is "as many as we can figure out how to get the mass for".
absent dismantling the gas giants themselves, you're not going to do anything very interesting do the dynamics of the solar system, regardless of what you take apart, or how you reconstitute it.
and the man-made structures can include mechanisms for closed-loop control of their position. which they'd need anyways, as they'd accumulate positional error from vehicles coming and going.
> absent dismantling the gas giants themselves, you're not going to do anything very interesting do the dynamics of the solar system, regardless of what you take apart, or how you reconstitute it.
I would consider reconfiguring available materials to achieve more usable surface area to be interesting (not to mention potentially useful if we manage to accomplish it someday).
However, what's "interesting" is highly subjective and dependent on context. Perhaps you meant something different by "you're not going to do anything very interesting" than the way some of us are interpreting it?
the orbital dynamics of the solar system. (the thing you'd be worried about if you thought you needed to learn how to make 416-body systems stable.)
certainly packing the habitable zone full of new places to live is interesting, on all sorts of social and technological levels. it just doesn't raise any questions about the stability/dynamics of the n-body system that is the solar system (until you maybe start taking apart the gas giants).
hopefully that clears that up?
And I agree; it turns out that planets are really heavy and have an incredible amount of inertia; moving some asteroids around isn't going to cause the Earth to slip on a banana peel and fall into the sun.
The original article about placing 416 Earth-sized planets in a stable orbit does involve a quantity of mass greater than Jupiter (at 317.8 Earth masses), but building habitats out of what we have available in and inside the asteroid belt is a much more modest scope.
Not that I disagree! We also have the Hilda, Trojan, and Greek asteroids (in Jupiter's Lagrange points) to work with. The Jovian and Saturnian moons too. It'll be a long, long time before we need to worry about dismantling the gas giants themselves.
On our path towards maximizing the livable land area in the Solar System, I wonder what we will run out of first. It looks like water, iron, carbon, etc. are all pretty abundant. We'll run out of* some rarer element (like Phosphorous or something) before we ever approach maximum constructed land area.
*And by "run out of", I mean even with perfect recycling, the spot market demand for the material maintains a price level where it's uneconomical to develop further, barring discovery of new supplies or more efficient usage.
Someone should make a VR app that lets you simulate the surface of any kind of planet and any kind of sky based on a solar system configuration.
Like the simulations of what will be seen from Earth when the Milky Way and Andromeda merge (https://en.wikipedia.org/wiki/Andromeda%E2%80%93Milky_Way_co...) but with hundreds of planets !
Even a render of the "binary earth" would be cool.
If we have habitable zone of 50 millions kilometers wide - just a rough number - then planet ring to planet ring distance would be 6 million kilometers, 20 times Earth-Moon distance. With 52 planets along the single orbit and orbital radius 150 millions kilometers (~billion kilometers circumference) the distance between planets on the same ring would be 20 millions kilometers. So I don't think planets would appear too big on the sky.
What I'm not sure about is how we'd deal with sea tides caused by binary planets. Even Moon causes significant tides; an Earth-sized planet would have to be much farther away than the Moon so it woudn't cause ever bigger tides...
http://store.steampowered.com/app/230290/Universe_Sandbox/
On steam there is Universe Sandbox^2 that has a VR version included. I don't think you can simulate the surface of planets, though. (I have it, but I haven't tried the VR version yet due to some persistent glitches with Oculus on many Steam apps).
You'd have to take that into account when doing your global warming models too.
Sun −26.74, Moon −12.74 (average full moon), Venus -4.89 to −3.82. So sun is around 400,000 times as bright as the moon, and the moon is ~1500 times as bright as the Venus which is bright largely because it's so close to the sun.
Mars is −2.91 at it's brightest. So 1/2 as much light as Venus because it's further from the sun even if it's closer. These might be closer than Mars, but not closer than the moon.
52 evenly spaced planets in an Earth-like orbit would be about (2pi600)/52 light seconds apart, which comes out to about 72 and a half light seconds. So, the closest neighbor planets would appear a lot smaller than the moon, but a lot bigger than, say, Venus.
I'm not sure how widely the adjacent rings would be spaced, so you might sometimes have neighbors that are closer than 72.5 light seconds as they zip by in the opposite direction.
The article also talks about arranging the planets as binary pairs, in which each planet might be very close to its neighbor, possibly appearing bigger and brighter than the moon from Earth.
Also, I'm wondering about tidal forces ...
Until some idiot on planet 297 moves his couch from one side his living room to the other. Then the whole system is going to slowly fall apart,
Previous discussion: https://news.ycombinator.com/item?id=14764125
It even links to the same site and the blog was posted by the same guy. I wonder why he's recycling content.
[0]: https://nautil.us/blog/a-letter-from-the-publisher-of-nautil...
Then it would just be a huge asteroid belt which would eventually form a normalized amount of planets.
1: https://en.wikipedia.org/wiki/Pierson's_Puppeteers#Homeworld...
I mean, our own solar system has more planets than "Pierson's Puppeteers".
Another unnatural thing about this model is that adjacent orbits rotate in opposite directions: according to existing theories of formation of planetary systems, it seems impossible for the gas disk to go into different directions in layers.
Anyway, this model is definitely cool (416 bodies in stable orbits!) and might be a useful blueprint for interplanetary engineering of the future.
> This system is completely stable—I double-checked with computer simulations. But nature would have a tough time forming this system. If it exists, it could only have been built by a super-advanced civilization. That’s why I call it the Ultimate Engineered Solar System.
But it'll send a pretty impressive message.
I would think that's a hilarious joke if the author didn't seem so serious.
And yes, that the N-body problem is chaotic.
Of course, when you're talking about a civilization building 416 equal-mass planets equally spaced in 8 counter-rotating orbits, worrying about how stable they are is kind of silly; as long as they're "mostly" stable the maintenance of monitoring and tweaking their orbits for a billion years would presumably both be feasible and cheap compared to the initial construction.
That said, the longer you simulate those orbits, the more certainty you have that they are stable. But you will never get a mathematical proof, because only symbolic math can ever prove things in a chaotic system, finite precision math can only deal with statistic degrees of certainty.
https://en.wikipedia.org/wiki/N-body_problem#n-body_choreogr...
obviously if another star smashes into planetary system - it won't survive, at least not in original form.
When the forecast says "60% chance of showers tomorrow", what he really means is that they ran a few billion simulations of the environment with very tiny perturbations of the initial conditions and in 60% of those simulations, it rained. In 40%, it didn't.
Tiny little changes in any variable in a chaotic system will, in the long run, lead to huge variations in outcomes.
This system with it's 416 planets has one outcome- perfect orbits constantly. But if you add a single 1 kg asteroid to the system, that would perturb everything ever so slightly. That slight change could result in the entire system chaotically coming apart from stability.
He said he came across that particular problem in a system which handled rounding numbers in a very suspect manner.
5-6 billion years is probably just fine.
On the other hand, the intense star flares and tidal locking seem very inconvenient.
Is it always such a big lifetime for small stars? White dwarfs have a long lifetime, but they have interesting stories behind them; what about other types of small stars?
Let's say we discover we are not alone. We know those aliens must not be from our galaxy, so do we push for development of faster-than-light travel? If so, why? Intelectual curiousity, defense, offense, trade, habitation?
As for the hypothetical galaxy with two planets of life: Are they developing the same? If not, do they, and if so why, expand to the other? If they are, are they afraid of each other? Do they have a "cold war"? The possibilities are endless.
Like Firefly, there are many posibilities for great sci-fi.
What? No, it's not.
Say you are an advanced alien civilization. And you reach the point where you haven't nuked yourself to death, so now you can expand into space. The first thing you do is to mine all the asteroids, that hadn't coalesced into a planet. So you spend all this energy to capture them, to smelt them, and then you build out your Dyson sphere.
You can achieve some coverage of the star, but is it even possible to cover the entire star with solar collecting panels, to capture all the energy output of the star?
At best, I think you might be able to get a ring around the star. But even this, is dubious.
https://en.wikipedia.org/wiki/Star_lifting
and possibly large scale transmutation. Disassembling the gas giants might be enough for some designs.
My understanding is that it isn't physically possible to construct rigid spheres or rings in that orbit, so it would be an orbital swarm of some kind, with the elements able to actively correct for the inevitable perturbations.
Most of the mass in a generic system should be in the planets, if I remember correctly from an old article here in Sol if we scrapped all the planets we could create a 3m thick Dyson shell. But a ring should be a lot easier to construct.
The interesting part of the article is the explanation of the different ways that the number of planets in the habitable zone of a star can be greater than one, and how it's possible that most stars have more than one habitable planet each. This has direct consequences for the Drake Equation and the likelihood of contemporary alien life in the galaxy.