4 ms·

If you spend 8 minutes getting the next chunk of information to your machine, and then another 8 minutes returning the result, it does not matter how fast your

If you spend 8 minutes getting the next chunk of information to your machine, and then another 8 minutes returning the result, it does not matter how fast your machines are or how many of them you have. You're still going to lose to the machines on earth, because the Bitcoin network on earth can already mine blocks faster than 16 minutes. Think of it this way. Say we're running a mile long race by foot, and it takes me an average of 10 minutes to run that mile. You want to bring a car onto the track that will be able to go a mile in 15 seconds, but it's going to take you 20 minutes to get the car to the starting line. That's how latency works. It doesn't matter how fast your machines are, by the time you've sent the information to them, by the time you've told them what they need to do, everyone else has already finished with their work and moved on to the next problem.

chii 6y ago
but with bitcoin hashing, you're testing out random hashes to see if it works, and there's an equal chance of finding one for all parties. But if you spend more computational power, you have a higher chance of find one (because you got more tries). Now, a satellite orbiting the sun has 8 mins of latency. Imagine if there was only 1 computer on earth, and 1 computer orbiting, and both "submit", it's the earth computer that's going to succeed first, if both finds a valid hash. Suppose we keep the speed of the individual computers are the same - but now you double the amount of computers orbiting the sun. Now you are twice as likely to find a valid hash - even tho it still takes you 8 minutes to transfer the valid hash message to the earth network. In that 8 minutes, if somebody else on earth finds a valid hash, they will beat you. But they only have 1 machine, and so their chance of finding a valid hash _must_ be half. So on average, the orbiting machines will get _some_ hashes through, because they get more tries. Some of their successful tries would just fail due to latency. At some point, there would be a tipping point where a large number of machines would be able to, due to sheer chance, always generate a correct hash! Now, of course, the latency will still be there, so the earth machines would have to rely on their luck to beat the 8 minute latency (which they will sometimes). What that tippig point is - might be a very large number - is unknown to me of course...and if that tipping point is greater than 50% of the available hashing power, then you might as well just forge instead of doing it for real...
- danShumway 6y ago
  > But they only have 1 machine, and so their chance of finding a valid hash _must_ be half. No, Bitcoin's network is currently set up to guarantee that a new hash is found in roughly 10 minutes. It's not about how many computers you have in relation to the earth, you need there to be few enough computers on earth and structural enough changes to Bitcoin's technology that it takes the current network on Earth more than 16 minutes to find a hash. Adding more computers to your orbital array will not change the hash rate on Earth, the network is set up to take the computing power into account and keep the hash rate at about 10 minutes. Go back to my footrace analogy. What you're currently trying to do is to beat me in a race by getting a progressively faster and faster car, or by introducing 2 cars into the race instead of just 1. None of that matters unless you can get your cars onto the track in less than 10 minutes, because in 10 minutes I will be done with the race and have moved on to the next hash. You're not pitting your computer network against the earth, you're just pitting it against the latency. You need the on earth hash rate to be slower than 16 minutes, which is not how Bitcoin is currently set up. > and if that tipping point is greater than 50% of the available hashing power, then you might as well just forge instead of doing it for real... To be fair, a 51% attack might actually be a feasible idea for your satellite network if you have enough computers there, but it would also come with the fun side effect of making all of your coins useless and crashing the bitcoin bubble. I suppose the other thing you could maybe do is get so many computers in orbit accepted into the network that you actually drive up the hash difficulty until all of the computers on earth can't solve the problem in 10 minutes; purely because the built-in hashing requirements of Bitcoin become so high that your network's computing power is necessary to finish the transaction in a reasonable time at all. I vaguely suspect you'd need at least close to 50% of the network to do that, but I might be wrong, I haven't done the math. The downside of that scenario is that you've now raised the hash rate for Bitcoin to 26 minutes, because the 10 minute hash rate is going to stay the same regardless of how many computers are on the network, even if 90% of them are orbiting the sun. But to be fair again, a 26 minute hash rate only matters if you're trying to build a working currency, which pretty much nobody in Bitcoin land seems to care about at this point.

chii 6y ago

but with bitcoin hashing, you're testing out random hashes to see if it works, and there's an equal chance of finding one for all parties. But if you spend more computational power, you have a higher chance of find one (because you got more tries). Now, a satellite orbiting the sun has 8 mins of latency. Imagine if there was only 1 computer on earth, and 1 computer orbiting, and both "submit", it's the earth computer that's going to succeed first, if both finds a valid hash. Suppose we keep the speed of the individual computers are the same - but now you double the amount of computers orbiting the sun. Now you are twice as likely to find a valid hash - even tho it still takes you 8 minutes to transfer the valid hash message to the earth network. In that 8 minutes, if somebody else on earth finds a valid hash, they will beat you. But they only have 1 machine, and so their chance of finding a valid hash _must_ be half. So on average, the orbiting machines will get _some_ hashes through, because they get more tries. Some of their successful tries would just fail due to latency. At some point, there would be a tipping point where a large number of machines would be able to, due to sheer chance, always generate a correct hash! Now, of course, the latency will still be there, so the earth machines would have to rely on their luck to beat the 8 minute latency (which they will sometimes). What that tippig point is - might be a very large number - is unknown to me of course...and if that tipping point is greater than 50% of the available hashing power, then you might as well just forge instead of doing it for real...

danShumway 6y ago
> But they only have 1 machine, and so their chance of finding a valid hash _must_ be half. No, Bitcoin's network is currently set up to guarantee that a new hash is found in roughly 10 minutes. It's not about how many computers you have in relation to the earth, you need there to be few enough computers on earth and structural enough changes to Bitcoin's technology that it takes the current network on Earth more than 16 minutes to find a hash. Adding more computers to your orbital array will not change the hash rate on Earth, the network is set up to take the computing power into account and keep the hash rate at about 10 minutes. Go back to my footrace analogy. What you're currently trying to do is to beat me in a race by getting a progressively faster and faster car, or by introducing 2 cars into the race instead of just 1. None of that matters unless you can get your cars onto the track in less than 10 minutes, because in 10 minutes I will be done with the race and have moved on to the next hash. You're not pitting your computer network against the earth, you're just pitting it against the latency. You need the on earth hash rate to be slower than 16 minutes, which is not how Bitcoin is currently set up. > and if that tipping point is greater than 50% of the available hashing power, then you might as well just forge instead of doing it for real... To be fair, a 51% attack might actually be a feasible idea for your satellite network if you have enough computers there, but it would also come with the fun side effect of making all of your coins useless and crashing the bitcoin bubble. I suppose the other thing you could maybe do is get so many computers in orbit accepted into the network that you actually drive up the hash difficulty until all of the computers on earth can't solve the problem in 10 minutes; purely because the built-in hashing requirements of Bitcoin become so high that your network's computing power is necessary to finish the transaction in a reasonable time at all. I vaguely suspect you'd need at least close to 50% of the network to do that, but I might be wrong, I haven't done the math. The downside of that scenario is that you've now raised the hash rate for Bitcoin to 26 minutes, because the 10 minute hash rate is going to stay the same regardless of how many computers are on the network, even if 90% of them are orbiting the sun. But to be fair again, a 26 minute hash rate only matters if you're trying to build a working currency, which pretty much nobody in Bitcoin land seems to care about at this point.