I'm sure that's how it will end up in a way or another. But the reason to think about a unified inter-planetary blockchain is that planets will trade with each other, and thus exchanges will be made in currency that will go from a planet to another, and will have to be valid on both. To do that, an inter-planetary blockchain will have to be synchronized, but will now face unavoidable delays, regardless of processing speed.
I think it will have to boil down to planet-specific blockchains, but maybe bitcoin can evolve to have two settlement layers within the blockchain, to allow inter-planetary trade. One settlement layer will be for the planet, nearly instant, and another, more delayed, will be for inter-planetary transactions.
L1 Bitcoin will work just fine on interplanetary scales, you'd just need to wait for extra confirmations compared with Earth time. Mining would only ever happen on Earth, though (maybe on the moon as well). Planets could have their own lightning networks.
reply
Sure thing! The problems I point out appear if mining decentralized among planets is attempted, which you would want if bitcoin is to remain decentralized. Otherwise, as space colonization advances, bitcoin will get increasingly centralized and likely dropped beyond earth, thus leading to a classic "international market exchange" scheme.
reply
That is what I was thinking. Something for each planet. Then maybe a currency exchange, or something similar when you want to trade between planets? Or just trade in goods?
reply
Any sort of currency exchange will imply for the currency to have a validation system in more than one planet, so what you just said seems very likely to me: transaction of goods will be a first robust way to trade. But, of course, it will soon face the same limitations it always had, and as with the economy on earth, there will be demand for a unit of account at inter-planetary scale. There's no reason why bitcoin can't be that unit, but at that point it will for sure imply a major evolution on the protocol, of which the technical aspects I refrain from project for I ignore too much.
reply
I think a major exchange will be goods. But will be interesting to see what kind of currencies pick up. It would have to be all digital, right? I dont see us printing money much longer.
reply
There might be a sort of intermediary currency, or directly replicating foreign exchange markets as @Undisciplined suggested. There will be no issue on trading at all, it will not get delayed a second in it's development. But the question is more about how a system like bitcoin will work in that context too, due to the importance we know it haves for our planetary economy, which will keep being true at inter-planetary scale.
reply
Yeah, I think there wont be a problem. Eventually they will come of with an elegant solution. Maybe they will put some printers up there just like the federal reserve.
reply
I'm certain that will not happen. Inter-planetary commerce will be on full control of entrepreneurship, governments will be powerless in the space-colonization era. Elon Musk will conquer Mars, not the US govt. What are they going to do? Summon him back to Earth? I can imagine Elon response: "Come in and chase me bitch? With what? What rockets? Mines?". Even today the US govt and Nasa can reach outer space solely thanks to Musk's launchers. No capitalist will bow unnecessarily to a FED system which is not only useless but even less powerful. You can safely forget about the pathetic FED era
reply
Haha I guess I didnt think along those lines. That is kind of true. What could they do?
reply
Musk controls space and planetary inter-communications even today. Only he is able to provide communication in Ukraine territory amidst a war. The US govt can't but to hire his services because it's incapable of providing such a critical defensive infrastructure itself. Elon has to be seated at every Pentagon meeting regarding national security ever since. Try to project where that will go once he haves an entire planet for himself with unlimited resources, if he is capable of this now while having to deal with a state which is only capable to use it's legal power to enforce transgender laws on children. The fight was over before it begin.