# Are there alternatives to mining asteroids/planets for obtaining matter?

I am reading We are Legion, by Dennis E. Taylor, in which humanity has developed the so-called 3D atom printer, briefly described as:

3D printers delivered individual atoms using a number of tuned carbon nanotubes, each sized for specific elements. (...) as you had to place individual carbon atoms, one after another, with zero defect.

They are able to print any material by placing individual atoms, and thus their only concern is obtaining raw matter. In the book series the main characters resort to mining asteroids and planets to obtain the raw material needed to 3D print things.

I wonder what alternative methods (if any) science fiction has given to sufficiently advanced civilizations for collecting massive quantities of raw matter. Something like mining dark matter, for example. Soft(er) science fictions are welcomed, too.

• In We are Legion, We are Bob, there is no transmutation of elements in the printers. They can create whatever molecules are necessary if they have the proper atoms. May 2 at 23:34
• The description sounds like it's merely placing atoms, but may not necessarily have the ability to transform any element atom into a totally different element atom. In which case you'd have to provide it with the element atoms it needs to build. May 3 at 2:44
• It sounds like this tech in We Are Legion is using "molecular nanotechnology". Check out Engines of Creation by Eric Drexler, who came up with, and popularized, the idea. May 3 at 8:41
• This technology is also important in Neal Stephenson's "Diamond Age". May 3 at 11:50
• @theonlygusti True, my bad, I assumed transforming atoms to different elements was included, but it is certainly not the same. Still, the question remains the same.
– D1X
May 4 at 16:43

# There's starlifting.

Basically, the idea is that you get a large (humongous) magnet orbiting the star (or hovering over it artificially via solar wind sailing), with which you attract magnetically charged plasma of the star's surface (but a couple of other means are described at the respective links).

You then collect the uplifted matter and can convert it to the materials you need by nuclear fusion and fission. Stars are easily the most prominent source of matter for a reasonably advanced civilization since even our own relatively small sun contains 99.8% of the mass of our entire solar system. The best part is that you can power your starlifting operation directly from the star itself, achieving basically cost-free production. And of course, it's very industrially scalable.

• Isn't this essentially what Starkiller Base in Episode 7 does? May 3 at 7:02
• I don't think you're going to use fission much. The composition of common stars is almost all hydrogen and helium, the two lightest atoms. May 3 at 10:05
• @MSalters there is still way more Uranium in the sun than in all the other planets combined. May 3 at 22:29
• Oxygen is essentially a trace element in our sun. The oxygen in the sun outmasses the entire earth by about an order of magnitude. May 3 at 23:21
• @PaŭloEbermann I would expect heavier elements to be closer to the core of the sun, and not so readily accessible. Am I wrong? May 4 at 8:29

Atomic transmutation (a.k.a. alchemy) is a gestalt technology. It changes everything.

Mining is the process of digging through masses of undesirable material to find the comparatively rare desirable materials.

When any material can be transformed into any other material at an atomic level, the whole idea of mining flies out the window.

Dr. Emmett Brown needs some energy for his time machine so he grabs a few random items from Marty's trash can. After pouring some leftover soda into the Mr. Fusion's input hopper, he drops in the empty can. After all, matter is matter. It's current specific form is unimportant.

So given that we have 5.972 x 10^24 kilograms of raw material right under our feet and given that every day, Earth is bombarded with more than 100 tons of dust and sand size asteroid particles, it is very unlikely that we will need to mine the asteroids any time soon.

If your device was created tomorrow, and if laws were passed that limited its use to existing garbage accumulated from just the last decade, the United States alone could provide more than 2 billion tons of raw material for transformation. Given this technology would allow us to go directly to the desired end product without all of the current byproducts and production waste, that decades worth of American trash would probably be enough to create a century of historically unprecedented wealth for the entire planet.

• So the U.S. isn't profligately wasteful! It is proactively stockpiling resources for future use! May 3 at 15:00
• Mining only flies out the window if you can perform atomic transmutation with low energy, which might be impossible. The energy demands are huge, particle accelerator huge. May 3 at 15:48
• Dr. Emmett Brown. Not that it matters. May 3 at 17:19
• Asteroid mining (or "transforming") still becomes profitable if you want to build things outside of gravity wells (like orbital habitats). May 3 at 22:31
• @kutschkem, we also endsthe life of 12-15 million cars per year and 100% of their weight can become transformation fuel. My theory is that if you compare any two days in the life of a first world person, the total weight change of current possessions is fairly constant. If you subtract the weight of my current possessions from the weight of what I owned last month, the change would be significantly smaller than the weight of my purchases during that time. If we recycle 100% then the dust only needs to keep up with our rate of change. May 5 at 22:30

If there is a powerful and abundant enough energy source, there is always the option of converting energy into matter, remembering that $$E=mc^2$$.

That would allow for creating directly any nucleon and from them any atom.

However mind that only to create 1 gram of matter one would need $$10^{15}$$ J. That's why I started with "If there is a powerful and abundant enough energy source".

• Expensive but do-able, assuming that the equation runs without great loss in both directions. If one gram of any matter can become almost enough energy to create one gram of matter, then cost doesn't matter. With such a device available, the economics of the universe is completely defined by the operating efficiency of the device. May 2 at 16:10
• @HenryTaylor "Good" news - because energy only creates particle-antiparticle pairs, you should end up with an equal amount of antimatter as the amount of matter you created. To get your energy back, just annihilate them and then collect the gamma rays. May 2 at 17:59
• How would you store such huge amounts of energy? How would you convert that energy into matter? May 4 at 12:30
• @theonlygusti we don't even know of any particularly efficient ways of converting the other way (mass -> energy), with I believe black hole maneuvers being the most efficient at around ~20%. May 5 at 18:36

## Make it using lasers

Just a couple of years ago, scientists discovered that an adequately powerful laser can be used to create matter out of a vacuum. If your advanced civilization has discovered some infinite or virtually infinite source of power, they may decide to simply fabricate new matter out of nothing.

Although this technology technically exists today, making it practical would require an extraordinarily advanced race due to the following complications.

1. Lasers need to be in the petawatt range just to be able to get the smallest of subatomic particles to form; so, when I say you would need a virtually infinite source of power, I am talking about a level of power generation that makes a nuclear power plant look like a potato.

2. You would probably also need to handwave in some kind of super material to make the lasers out of since anything we have today will probably degrade faster than you could use it to generate replacement parts.

3. Another problem with this is that for every particle of matter that you make, you are also creating an equal mass of anti-matter which will of course need to be seperated, contained, and properly disposed of. Containing and disposing of anti-matter is no simple task, for this I would recommend dumping into the nearest black hole just to make good and sure it does not accidentally drift into any normal matter that you might care about.

4. Lastly, every proven source of power that we know of requires at a very minimum, the same amount of mass going into your reactor as you have energy coming out. So, for your civilization to "make matter out of nothing", it means that they need to first "make energy out of nothing". Both of these ideas are more or less impossible under our current understanding of physics, but the later at least has some theoretical possibilities.

## How an advanced civilization might do it

It is very difficult to generate energy from nothing, but there are a few devices believed by some to be able to exploit the permanent binding energy of nature's fundamental forces like gravity or magnetism to produce net gain energy outputs from a system. While these devices are a bit controversial, and not super efficient, a future tech civilization might be able to grow these technologies into effective sources of energy.

For example, a gravity pinwheel engine placed close enough to a black hole might produce extraordinary amounts of power compared to our weak 1G powered variety. As a bonus, you could dump your unneeded antimatter safely into the black hole which you are already exploiting.

# Recycle

For a growing civilization, you'll still need a net increase in total mass to keep things going, so this won't eliminate the need for mining. However, I'm sure there will be plenty of trash and other unused matter that can get thrown back into the machine.

This answer is inspired by the 2-part "Year of Hell" episode from Star Trek Voyager, where Janeway throws her watch into the replicator for a few more days of food.

Create a pocket universe. (or just find one) Keep it contained yet accessible. Trigger a big bang and expend it enough to cool. Once cool enough matter will form. Extract the matter from that universe to the one you are in.

Or,

Mine the Past. (with a nod to the Strugatsky brothers) send pipelines and other implements into the past and get the goods before they were mined. You already know where they are and how good the quality is.

I've also seen fiction that 'mines' the dark-energy field, basically slowing down the universal expansion by an immeasurable amount. But at that point you might as well just say 'magic'.

• Or dark matter, really. There's so much dark matter flowing through everything, if you could extract the energy from it, you'd pretty much have a magical solar panel with orders of magnitude higher energy flux that also works at night. Could make for an interesting hard sci-fi story even, as people a few million years in the future realize what the "free energy" "mining" is doing to the galaxy :D May 4 at 11:56

Nebulae contain incredible amounts of resources (they are, after all, the remnants of supernovae) although said resources are generally incredibly diffuse, e.g. a nebular cloud the size of the Earth would have a total mass of only a few kilograms. So they're probably not an efficient option, unless you're able to find the denser areas.

Well - if you really 'just' wanted matter, there's apparently hydrogen out in interstellar spaces. While its meant for reaction mass for a rocket, you could essentially use something like a bussard ramjet as a way to harvest it, and fusion to produce helium.

I'll leave it to the reader to work out how to turn a healthy breakfast of the neutrons, electrons and protons of helium, and the electrons and protons of hydrogen into other elements, and how the energy requirements make sense.

• What's a bussard ramjet? How an it harvest interstellar hydrogen? May 4 at 12:32
• See the link - its literally a large scoop that scoops up hydrogen as it passes. The ramjet pretty much compresses and fuses it for power, in theory May 4 at 12:35
• It seems to be more complex than that, and very interesting. I think it would be great to add into the body of the answer itself, especially since you're modifying the original ramjet (which is a hydrogen-compressor/fusion reactor) into your own hydrogen-collector. May 4 at 12:40

Attach propulsion systems to asteroids and crash them on a planet or airless moon where traditional mining techniques can be used.

• ... you still have to mine a planet then; isn't this just moving the problem around? May 3 at 15:07