Topic: "Ladderdown" and interstellar economics

[GrumpyOldFart]

The most 'dense' methods of energy production (by many orders of magnitude) thus far discovered are fission and fusion. 'Magneto-gravitic' energy production, while perhaps possible, could not reasonably be expected to be independent of the shape of local space in which it operates. Therefore the same methods of producing energy by magneto-gravitic means could not be expected to yield the same benefits for the same risks from planet to planet or from star to star, much less in open space far from external gravitational influences. In short, you couldn't expect the consistency you would from fission and/or fusion. As well, magneto-gravitic energy production would presumably derive its output from the shape of space, and the Law of Conservation of Energy suggests that a large enough energy production (such as needed by, say, a densely populated advanced culture) would, over time, result in some form of 'gravitational erosion' to the very shape of local space itself.

Fusion is the transformation of light elements into heavier ones, at or below the atomic weight of iron. Fission is the transformation of heavier elements into lighter ones, at or above the atomic weight of iron. While it is possible to extend fusion to heavier elements than iron, and fission into lighter ones than iron, the resulting reaction is endothermic, meaning it requires more energy input to cause the reaction than the reaction itself produces. While possibly being useful as a heat sink for a civilization needing to deal with mass amounts of waste heat, such reactions are worse than useless for purposes of energy production.

Combine the above with the fact that elements lighter than iron appear to be much more common than elements heavier than iron, and it suggests that the clearest indicator of a system's value to an interstellar culture would be the metallicity of the parent star(s). A reasonable balance of light and heavy elements would allow both “laddering down” fission of heavy elements and “laddering up” of light ones, until the common waste product of almost any energy production would (eventually) be iron. In a practical sense, the higher a system's metallicity, the more access the controlling civilization has to the “other side” of the energy production equation.

While various stellar/planetary systems may be considered valuable for an abundance of unusual and/or complex chemical combinations of elements (such as RNA/DNA), nonetheless once fission and fusion are fully mature technologies there really is no such thing as “Unobtainium”. There can't be, the civilization is capable of producing any element in existence, it's only a question of whether it's worth the trouble.

Caveat: Taking note of the waste heat issue above, very old civilizations might not value high metallicity systems to the degree younger ones do, as the heat sinking possibilities of endothermic fusion reactions may become a major factor in perceived value in and of themselves.

Thoughts, comments?

[markc]

 1) if your science is correct (I do not know the feasibility of making any element greater then iron with fusion. IMHO you would have to look at phase diagrams to determine the feasibility and then you have to look at the time required. If you can find a catalyst for the reaction then that makes a huge difference.) then I would say yes your thoughts are correct.
 2) you only look at 2 forms of power where as in the future other known forms of power might become more efficient than they are today.
 3) we may discover an unknown form of power that makes other forms obsolete.
 


 If you think about most power production today, it simply boils water into steam to turn turbines for electricity. I would hope in the future there would be a better way (more efficient, modern {if that can be said}) to generate electricity than the simple steam engine.
MDC     

[GrumpyOldFart]

1) if your science is correct (I do not know the feasibility of making any element greater then iron with fusion. IMHO you would have to look at phase diagrams to determine the feasibility and then you have to look at the time required. If you can find a catalyst for the reaction then that makes a huge difference.) then I would say yes your thoughts are correct.

I'm no scientist, I'm just taking the assumption of fission/fusion are fully mature technologies = it's now the craft of building elements to order out of subatomic parts. What you and I call fission and fusion are in its infancy by comparison.

2) you only look at 2 forms of power where as in the future other known forms of power might become more efficient than they are today.

Lots of varieties of planetary power sources are available, but they all vary with local planetary conditions. Even if you're talking about solar power in space it still varies from star to star, which is "local" in an SF game.

3) we may discover an unknown form of power that makes other forms obsolete.

Sure. But if it's implied by the physical laws we already know, or at least doesn't directly contradict them, we can story-build consistently just by speculating within those boundaries.

And if it's not implied by the physical laws we already know, or does seem to directly contradict them, the only practical limitation is each individual GM's imagination, so there's no real point trying to plan (or story-build) around it.
 

If you think about most power production today, it simply boils water into steam to turn turbines for electricity. I would hope in the future there would be a better way (more efficient, modern {if that can be said}) to generate electricity than the simple steam engine.
MDC     

Me too. But the waste product of almost any energy flow of any kind is heat, so that's always going to be the easy one. Given that, presumably a culture could reach a population density and energy efficiency such that their own society's waste heat is sufficient to power nearly everything. But no matter how close they get, unless there is such a thing as perpetual motion there will always be a difference to make up. And of course, the denser the population the higher the number affected by any failure to make up that difference.

Most of humanity's use of "power" has been nothing more than moving heat around, which creates its own problems because of course that isn't 100% efficient either.

[markc]

 I can say that we as of right now have trouble just building an element out of other elements (ie lead into gold) and assuming that it will be possible in the far future is a bit of a stretch, IMHO. It is not quite as simple as slamming protons (and maybe neutrons) into another element to build it up to what you want or like wise you cannot just take a knife cut off parts you do not want of a element to get what you want.
 But OTOH it is commonly assumed you can do things like print things you want (molecular printing), have holo-decks with feeling, etc in the future. So I do not see a big problem with what you want to do.
 One thing I would do is try and see how someone could abuse your idea and see if it would be a fun Universe to play in.
MDC

[GrumpyOldFart]

I can say that we as of right now have trouble just building an element out of other elements (ie lead into gold) and assuming that it will be possible in the far future is a bit of a stretch, IMHO. It is not quite as simple as slamming protons (and maybe neutrons) into another element to build it up to what you want or like wise you cannot just take a knife cut off parts you do not want of a element to get what you want.

Neither is building, say, a radio out of what is essentially rocks and rotten plant matter.

Just sayin'.   

But the point is to assume the fusion/fission process has gotten so well understood that you're able to design according to available fuel, whether waste heat is a problem, and even what kind of waste you're willing to have from the process. If it's well enough understood, the waste from one process can be the fuel for another one.

Kind of like how we understand turning fire into motion well enough now that if we can't run a car on gasoline, we can run it on natural gas, battery power, even coal or wood if need be. Apparent efficiency changes, but within the context of local conditions it adjusts itself to optimum. Nobody cares how efficient your gasoline engine is if there's no such thing as oil where you are. We've got lots of trees, and we can grow more.

But atoms are everywhere. 

Especially near lightspeed. 

[markc]

But the point is to assume the fusion/fission process has gotten so well understood that you're able to design according to available fuel, whether waste heat is a problem, and even what kind of waste you're willing to have from the process. If it's well enough understood, the waste from one process can be the fuel for another one.

But atoms are everywhere. 

Especially near lightspeed. 

 What it sounds like is that you are saying that for your Fusion-Fission drive you can use anything for fuel. In essence unlimited energy but depending on the source of fuel it may take more or mass or less mass depending on what you are using.
 If you are thinking about using multiple sources of fuel at once (that are dissimilar from one another) I think you would still have a big problem unless you could build the F-F Power Plant in such a small scale to provide multiple reactors for such different fuel sources.
MDC

[markc]

  I forgot to say that I will do some reading on Fusion and Fission so I am a bit more up to date as I have not looked at the science except for the basics, for about 20 or so years.
MDC

[GrumpyOldFart]

I wasn't thinking so much in terms of drive as power source, such as planetary power grid. The nice thing is that you don't have to go to a different design because you're on a space station. At high speeds you could use a variation on a Bussard ramjet to gather fuel, and yes you could use it as a drive.

So on a planet, when you run out of _____ that you're using for fuel, recalibrate and switch to something else. At a space station, calibrate it for your local fuel and leave it that way. On a ship, calibrate it for interstellar hydrogen, but be prepared to quickly shut down and have to recalibrate your system if you run into, for example, a formaldehyde cloud. Once that's done, you can "burn" the formaldehyde.

In essence unlimited energy but depending on the source of fuel it may take more or mass or less mass depending on what you are using.

Exactly. You might have to "re-spec" when you run out of a particular type of fuel, but you don't have to redesign.

[markc]

 Giving it some thought during a poor sleeping night I have remembered that there is a problem with just throwing anything in as it can require more energy to break apart the reactants to get the products you want for an efficient reaction.
 I can see you using the product of a reaction that produces H(sub)2 for your Fusion reaction.


  IMHO you might want to look up the expected yields for the 10 most efficient reactions for each type of power to see what you might get. I think that the power yield can drop off significantly in some cases. But I also could be wrong.


 I do like the idea a lot.
MDC