Making Planets

JoshNH4H · 2008-01-12 09:15:46

To start, I would like to say that I am talking VERY far future here, and that this would probably be done in other star systems.

The idea is that you get some iron out of a star, and form it into a planet. You wouldn't really have to form it, as gravity will naturally formi t into a sphere. The iron will probably be liquid when it comes out. My caculations show that an iron body 5000 km in diameter wil have .6 g's. This will be pretty good for health, and with an orbiting moon with a diameter of 800 km, the core should stay liquid and develop a magnetic field. The moon will have .1 g's. There would also probably be some nickel mixed in.

Remember that this idea is in the somewhat far future. What do you think?

Terraformer · 2008-01-12 09:58:46

Very Douglas Adams Hitchhikers Guide here. I like it.

Chances are the Iron wouldn't come from a Star though. It would be uneconomical to lug the Iron lightyears (no stars can have Iron in them, the collapse into neutron stars or black holes, so you won't be able to find stars you can take the material from and build around) when any Star without any planets to be terraformed to the specifications required would already have plenty of Asteroids and Comets to use.

JoshNH4H · 2008-01-12 12:46:40

well, a second, third, fourth generation etc. star would have quite a bit of iron from the stars thatt preceeded it.

Just thought of another benefit- make the landscape. when it's still semi-molten, just make whatever depression/ hill you want to make lakes, oceans, valleys etc.

I would suggest this would be done in a binary star system with a preferably m9 star orbiting a more sunlike (G0) star. This would be to minimize gravity wells to be overcome.

Terraformer · 2008-01-12 14:14:51

But why go to all the expense of mining a star when there are plenty of star systems with Iron/Nickle asteroids in. The planet would have a massive iron core, a mantle of say salty water, and a layer of Pumice? for the crust. That way you get a magnetic field without having to keep Iron molten.

JoshNH4H · 2008-01-12 14:19:42

Firstly, because it didn't occur to me.

Secondly, because you only need to do two extractions of any sort for this, 1 for the planet and 1 for the moon. Also, if there's an earthquake and the pumice breaks, 20,000 leagues under the sea will seem like nothing

Terraformer · 2008-01-12 14:24:34

Lol. But there must be some kind of conducter that we don't have to keep molten. Any metal will do so... ...aluminum anyone? Molten at a very low temp (the foil alloy does).

JoshNH4H · 2008-01-12 14:28:25

there's mercury, but not nearly enough in any solar system to make a mag. field. But you're talking about moving asteroids for the planetary core. Just move one more big one, and use it as a moon to keep the core liquid.

Terraformer · 2008-01-12 15:01:26

Actually, I was talking about using the Asteroids for resources instead of stars.

JoshNH4H · 2008-01-12 15:06:25

I know, so we could use 1 more as a resourse, and change it from being an asteroid to being a moon.

karov · 2008-01-13 04:15:35

making planets? very easy.
take KBO = from 1 to 50 Earth masses estimation
take Oort cloud = from 1 to 1000 Earth massess estimation.

Use tethers / space elevators / orbital rings to gently deorbit, decelerate smaller debris onto initially huge bodies there. Thus you avoid heating, AND generate electricity. The electric energy transmitted by Bolonkin plasma cord is used to pull together everything in radius of as much as billions of km. ( visualization: these hairy "plasma lamps" )

IE, the process is SELF_POWERED because of the positive energy ballance of the putting things to fall into gravity well which goes deeper and deeper with every piece of mass.

If in the radius of 10 000 AU ( the Inner OO ) which some estimate contains up to 85% of the competary mass ... we got , say 10 Earth masses , than we can make 100 mars-size bodies with moon-level of gravity ( due to the lower density ).
The OO-planets may be condensed closer to the Sun, in order to be utilized ALSO the solar-orbital energy of the used mass...

Illumination? Easy -- with OPTICS ( remember ) one could achieve earth level of insolation on distances from Sun-like start of as much as 4-5 LIGHT YEARS, and as little as 4-5 solar radii. Also using tethers to gently pile up the planet, one has constant supply of electrical energy DURING construction.

Given the recent scientific articles about QUADRILLIONS of ~100m bodies detected in KB, the trend the estimations for size and number disribution of the little bodies in the SolSys ( the Main belt - 4-5M bodies >1km, not 1M, the Jupiter trojans more than the Main belt asterroids, Neptune trojans at least 20 times more than Jupiter ones... ) to increase with orders of magnitude... , the maths of the SolSys rotation momentum... showing possible 0.03 Solar masses of the population of the OO ~ 1000 Earth masses. ...

To build ( say! ) 10 000 Mars-mass habitable bodies on ( say !) 100 AU from the Sun for several centiries, is not so SF.

JoshNH4H · 2008-01-13 08:14:24

Sounds great, but the already existing planets and moons might be in a little danger.

Antius · 2008-01-13 15:36:40

To start, I would like to say that I am talking VERY far future here, and that this would probably be done in other star systems.

The idea is that you get some iron out of a star, and form it into a planet. You wouldn't really have to form it, as gravity will naturally formi t into a sphere. The iron will probably be liquid when it comes out. My caculations show that an iron body 5000 km in diameter wil have .6 g's. This will be pretty good for health, and with an orbiting moon with a diameter of 800 km, the core should stay liquid and develop a magnetic field. The moon will have .1 g's. There would also probably be some nickel mixed in.
Remember that this idea is in the somewhat far future. What do you think?

How would you get the iron out of the star in the first place? the surface temperature of the sun is 6000+degC. Even low mass red dwarf stars have surfcae temperatures exceeding 2000degC. Extracting material from a star would also mean braving intense radiation fields. The investment of energy would also be large, given that even the smallest stars have masses 13 times that of Jupiter.

My guess is that a civilisation would need to be seriously short of raw materials before going to this much trouble. If materials really are that valuable and expensive, it would be FAR cheaper and more efficient to build small rotating colonies, with physically contained atmospheres (ie, O'Neill type colonies).

Using gravity to hold down the atmosphere of an artificial world, is a very material intensive way of creating habitable area. This is simply because gravity is such a weak force and you need a great deal of mass to create significant gravity. For every square metre of land on Earth, there are 10million tonnes of raw materials. That's an awful lot of material for just 1sq meter of land. Building a habitable world in this way would be unimaginably expensive, especially if all the material required has to be lifted out of the full depth of a star's gravity well.

JoshNH4H · 2008-01-13 20:15:17

I was imagining playing with the star's magnetic field so that it ejects the iron for us.

You're forgetting one thing: Planets are sustainable. If a meteorite hits the planet, then you won't lose everyone because the hull is breached.

Antius · 2008-01-14 02:23:56

I was imagining playing with the star's magnetic field so that it ejects the iron for us.

You mean like, creating an artificial solar flare? How would this work exactly?

You're forgetting one thing: Planets are sustainable. If a meteorite hits the planet, then you won't lose everyone because the hull is breached.

This is a non-issue. Firstly, we are not talking about single habitats here, but millions. If a large meteorite hits a single colony, you build a new one and none of the other colonies will be effected by the event. Large impacts will be very infrequent events anyway. Damage from smaller impacts will be reparable without the need to evacuate the colony. Impacts large enough to completely destroy a colony would occur on million year timescales.

Secondly, with a planet, all of your eggs are in one basket and a single large impact will devastate the entire planet. The planet's gravity actually worstens the situation, by effectively increasing its cross-section to impact.

But ultimately it comes down to economics. With the earth, we need ten million tonnes per sq metre of material under our feet just to provide 1g of gravity. With a rotating colony, we need perhaps 10 tonnes in total. So that's a factor of million difference in cost.

JoshNH4H · 2008-01-14 15:04:15

About the solar flare, I'm not exactly sure. However, Maybe temporarily heating up the star's photosphere by churning up the lower convective zone, then directing iron to that spot magnetically.

We're talking far fuuture here, I know, but you may underestimate the value of open space and a magnetosphere.

karov · 2008-01-15 04:34:47

Paul Birch www.paulbirch.net states that processing the solar plasma ( i.e. mining the sun ) we could harness 1000 times more energy than by simply tapping the outcomming EM radiation. I think the ( normal !) solar wind and solar radiation could be utilized so such artificial solar flares, corronal mass ejections, etc. DIRECTED outbursts of hot material to be achieved. Acc. to the VIrial Theorem the Sun hydrostatic equilibrium is based upon the internal heat which if utilized could suiffice exporting HALF of its mass ad infinitum.

SO, energy-wise to mine the sun, or any other start, is lucrative business - that gives mass & energy profits. Yes, the stellar gravity wells are deep, but the essence of any star equilibrium is so that any star is permanently on the rim to "spill over". It needs only gentle nudge to "beech fire".

Having inmind that the stellar meteorology is even more comlex than the planetary ones, due to the tremendous energy density involved, as with any hyper-complex entity/ process/ system to MANAGE the sun output of mass & energy the problem is in INFORMATION processing , not in outside-comming energy available. = the butterfly wing principle.

Simple analogy: 100kg falling stone, and a man with a gun possesing similar level of energy. To divert the stone from falling one needs almost as much or more energy than the gravitational potential realization from tha fall would release. Falling stone is dumb process == predictable = LOTS of energy, LITTLE information. The guy with the gun could be diverted from shooting by TELLING him / her. LOTS of ENERGY, LOTS of INFORMATION. The second system possesses tremendous complexity, but could be managed with miniscule amount of energy.

Hence "Karov`s Law" -- as more complex is the system, as less energy needed , and as more information needed for its regulation.

I think mining the stars is imminent. The separation of the harvested stellar plasma is easy using a-la-BIrch magnetic centrifuges , and for production of really massive quantities of astronomical metals ( i.e. anything with Z higher than the Z of H & He ) , ONLY the mass scale non-stellar and non-gravity confined nuclear transmutation tech will outcompete it in terms of efficiency and productivity. ( Here to note that the Lawson criterion is AGAIn matter of how much information we process in the fusion process, not the ENERGY we involve ).
In the Sun we have several thousands of Earth masses of Carbon and Oxygen per instance == here you are the source of all the material for dozens of light years long topopolis colony...

Back on "making planets" -- yes, rotating colonies are millions and billions of times more mass-efficient than natural and artificial planets / planemos.

From the other hand coallescing planemos out of any sufficient reservoir of available debris is self-avalanching process. It is like "syphoning" cause due to the negative energy nature of gravity, as more one stuffs a gravity well as more the well can house, it gets deeper and deeper. The potential gravity energy for it gets greater, bigger energy yeald.

Example:

If the central body has radius R, then the additional energy of an elliptic orbit compared to being stationary at the surface is

For the Earth and a just little more than R / 2 this is (2a － R)g ; 2 a － R is the height the ellipse extends above the surface, plus the periapsis distance (the distance the ellipse extends beyond the center of the Earth); the latter times g is the kinetic energy of the horizontal component of the velocity.
Pluto mu = 871
R = 1 195 km
a = 19 571 km

Rate of change of the specific orbital energy for Charon mass vs. being stationary onto the Pluto surface is

0.7 MJ/kg or 700 000 J/kg

descending the whole Charon onto Pluto via tethers / orbital tower / bridge / ring, etc. ( mass of Charon = 1.52x10exp21kg multiplied by 0.7 MJ / kg )

gives total of ~ 10exp21 MJ Orbital Energy Reserve

or 10exp27 J

if downloaded ~1.5 tonne / 1500kg of Charon stuff on Pluto per second , it is power of ~1GW for ~ 10exp18 seconds long

or 2 TW which is

1.7 TW - Geo: average electrical power consumption of the world in 2001 , give times better efficiency, effectivelly it would be at least 5-10 times better usage and effect than
3.34 TW - Geo: average total (gas, electricity, etc) power consumption of the U.S. in 2005 [3]
or more like...

15 TW - Geo: average total power consumption of the human world in 2004
equal to 3000 tonnes or 3 000 000 kg per second.

Charon will last for 5x10exp14 seconds drained down to Pluto with rate of 3M kg per second...

16 million years!!! of today`s earth-world energy consumption ABSOLUTELLY independent from solar power.

============================================

Pluto apparently is pretty good "seed" for accumulation of bigger body. NOTICE that the seed is constantly habitable cause the mass influx is managed via orbital towers, hence no sudden thermal release of energy as with meteor strike or spontaneous planemo collapse.

There are at least 200 to 1000 planemos only in the KB. Perhaps millions in the OO.

NOw imagine manageable mass-concentrating of a molecular cloud = predecessoir of a star system. You still have a nuclear rwctor in the center, but at least half of the mass around it is habitable shells -- from one Solar mass == trillions and trillions of earth surfaces equivalent of habitable shirt-sleeve environment... and all the "brain power" to fuse all the H&He up to Iron...

Terraforming possesses REALLY wide meaning.

Terraformer · 2008-01-16 12:31:56

Or find a white dwarf and carve it up into balls of diamond with just little below one G. Dunno how big each ball would be though.

Once fusion is developed it could be used for more than just producing energy. Even if it only nearly breaks even it could be used to turn interstellar gas into elements all the way into Iron. I can imagine a colony ship, powered by fusion, growing using materials from the interstellar medium.

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