>> Mostly the claim that "The Difficulty is Intergalactic" is just flat wrong.
(I wrote the article) - I see your point, but I think the article is still correct. Now communicating the winning block is a problem, as you pointed out, so as a miner on Mars you're at a disadvantage, but that statistically the probability of solving the puzzle remains same regardless of your location in the universe is still true.
As someone else pointed out - for the intergalactic version we'd need an interval much longer than 10 minutes.
This is why 10 minutes was chosen by Satoshi probably - it's plenty of time for everyone to communicate the solved block, yet not too terribly long in "human time".
While you don't have to report that you failed to calculate a hash, it matters that, had you succeeded, you would have reported it. Someone who calculates hashes with no ability to report them shouldn't count as a participant.
To put it another way: if there is a group of participants with spotty Internet that, after succeeding in calculating a hash, have only 10% chance of actually reporting it, then working backwards, we need to divide by .1 (multiply by 10) to calculate the number of participants. But if they have a 0% chance of reporting success, then we'd have to divide by zero. This is because they aren't actually participants. It's attempting to count non-participants.
I stand by my point though, for the purpose of totally ordering blocks, the difficulty is not intergalactic because a solution on mars is much less useful than a solution on earth. The problem here is time-delay preventing simultaneity. This is the same problem that block chain time-stamping hopes to solve. Thus it seems unfair to me to ignore this problem.
I wonder how tight the 10 minute mark is at the moment. I imagine there might be nodes that are 5 seconds apart on the network. Maybe even more when we have backhoe outages. How much lower could the 10 minutes be before we start seeing to many orphans even on earth?
If there is no double spend between the later arriving block from mars and the block earth already mined the next block could acknowledge both. Basically making the blockchain a blocklatice. If I haven't missed anything the only reason it wasn't done like this from the beginning is that when the orphan rate is low it' not worth the additional code complexity.
Interesting! A block lattice seems like a nice thing.
It would be problematic with regards to money creation though. As we get more blocks per 10 minutes, we get more block-rewards (new bitcoin) per minute.
It also seems weird to 'amend' history by saying some other stuff also happened.
Thinking of this, could you maybe use this to somehow block a payment by adding a 'past block' that already spends the bitcoins in your payment?
> the difficulty is not intergalactic because a solution on mars is much less useful than a solution on earth
We're talking apples and oranges, I don't think there is a disagreement - I was only saying that the statistical problem is "intergalactic", not that how it's used in Bitcoin is useful across galaxies. The fact that the probability of the outcome is same across the whole universe is what I found particularly remarkable.
I am working on a project that’s cryptographically encoding passage of time as data, with a millisecond resolution. https://github.com/solana-labs/solana As long as the fabrication process is the same you can have high confidence at time and order of events that are far apart.
A long enough interval could work within the solar system, but without FTL communication, an actual intergalactic version would require intervals longer than human lifespans.
It seems to me that different solar systems wouldn't be able to maintain a single blockchain, they'd each need their own.
In Neptune's Brood there were "slow" currencies where transactions had to be settled by communication with other star systems. It was created as a deliberate way to drive colonization of new star systems, since the only way to create more of it was to colonize more systems. The founders of a colony could end up quite wealthy, if they survived the attempt.
Of course, for every-day transactions there were also "fast" currencies where transactions were settled more or less instantaneously, and "medium" currencies where it would take longer but still be reasonably quick (probably for transactions between parties on different planets in the same system, but I don't recall that it was specified exactly).
Since I won't have time to read this book for at least several months - what are those colonists able to spend their newfound wealth on? Goods that will have to travel from lightyears away?
There is some physical trade between systems in the book (it's cheaper once you know you won't have to build a civilization on the other end), but there's no real enumeration of the possibilities in the book.
Given the characters seen in the book, I think founders mainly try to set themselves up as president for life of some planet or moon in the new system. Another example shown in the book is emigration; once you're sufficiently wealthy you emigrate back to some place nice where you can enjoy it. Of course that requires building a starship, which pretty much requires setting up a successful civilization that can support a starship industry.
(I wrote the article) - I see your point, but I think the article is still correct. Now communicating the winning block is a problem, as you pointed out, so as a miner on Mars you're at a disadvantage, but that statistically the probability of solving the puzzle remains same regardless of your location in the universe is still true.
As someone else pointed out - for the intergalactic version we'd need an interval much longer than 10 minutes.
This is why 10 minutes was chosen by Satoshi probably - it's plenty of time for everyone to communicate the solved block, yet not too terribly long in "human time".