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Earlier quoted context omitted.
Thanks. Why can't all math teachers talk like that? I mean... I know you're clever and all, but if you were really clever you'd explain it in a way that's easy to understand. Still, kudos to the OP. That was a great attempt to be precise.
Understanding is one thing, explaining in layman or easy to undertand terms is another, and sometimes it takes a lot of effort.
You guys would love Richard Feynman.
TLDR: Since blocks that take a long time to mine fill up more wall-clock time, if you pick an arbitrary instant of wall clock time, you're more likely to be in a "slow" block than a fast block. Specifically, you expect to wait 2x the average.
I've been thinking about the game theory aspect of that, and it's a bit hard to work out whether that will cause even more miners to flee. If so, that could very well be a death spiral.
It's hard because transaction fees might make up the difference. Though it's hard to imagine everyone being ok with >$100 transaction fees.
While the average difference in time between one record and the next is 10, the weighted average over the entire duration is 20.
This is why I like block times of 2.5 minutes that Litecoin does. Rarely the block takes over 4 minutes. So even if it takes a couple of blocks, it's still within 10 minutes. Even 5 minutes a block would be better than bitcoin's 10. With bitcoin, if you put a reasonable fee, but your transaction doesn't make the next block, it can take more than an hour, which makes impractical certain transaction types like online s…
Most simple criticisms of why Bitcoin does things the way it does and then suggestions for simple ‘improvements’ such as yours (5 minute interval) tend to be naive and wrong. The 10 minute interval for Bitcoin transactions was chosen as the best tradeoff to balance pros and cons for making it shorter or longer. Stackexchange has a good discussion on the topic: https://bitcoin.stackexchange.com/questions/1863/why-was-…
[1] http://www.tik.ee.ethz.ch/file/49318d3f56c1d525aabf7fda78b23...
Earlier quoted context omitted.
This reminds me of headwinds in airplanes. You might think that on average, wind cancels out. Sometimes you have a tailwind, sometimes you have a headwind and over time it will all average out. This is not the case. On average, wind reduces your groundspeed. The short of it is you spend more time in a headwind, so you spend more time experiencing the bad than good. There's also the fact that even a direct crosswind s…
Wouldn't cross wind cancel out in average though? (even though head and tail winds don't)
Imagine an airplane that flies 100mph. You want to fly north, but you have a 90pmh crosswind from the east. You have to point almost directly into the wind just to keep from getting blown off course. You can turn a little to the north, and you'll go very slowly. If you instead have the wind come from the east, you still have the same problem.
Maybe easier analogy: to get directly across a river, would you rather swim across one going fast or slow?
TLDR: Since blocks that take a long time to mine fill up more wall-clock time, if you pick an arbitrary instant of wall clock time, you're more likely to be in a "slow" block than a fast block. Specifically, you expect to wait 2x the average.
If a bunch of miners decide to flee Bitcoin, it might take an hour or more to mine a block. I've been thinking about the game theory aspect of that, and it's a bit hard to work out whether that will cause even more miners to flee. If so, that could very well be a death spiral. It's hard because transaction fees might make up the difference. Though it's hard to imagine everyone being ok with >$100 transaction fees.
If we acknowledge the propagation delay, their expected profit increases slightly because of the reduction in the probability that their blocks would be orphaned.
Additionally, the increased congestion would likely increase the transaction fees, further increasing the per-block profits.
Once the network readjusts and the difficulty decreases, the remaining miners would see a windfall profit.
The potential death-spiral would only come if the temporary increase in delay causes the value of bitcoin to fall, in which case more miners will likely flee. If this happens fast enough, the blockchain may never reach its next adjustment.
Earlier quoted context omitted.
This reminds me of headwinds in airplanes. You might think that on average, wind cancels out. Sometimes you have a tailwind, sometimes you have a headwind and over time it will all average out. This is not the case. On average, wind reduces your groundspeed. The short of it is you spend more time in a headwind, so you spend more time experiencing the bad than good. There's also the fact that even a direct crosswind s…
That's really neat, thanks! An interesting related fact is that with equal distance traveled through headwinds and tailwinds a slower plane will be relatively more affected. From ~12% longer time with a wind speed 1/3rd plane speed down to ~1% with a wind speed 1/10th plane speed.
Earlier quoted context omitted.
Can you explain the multiple meanings you see in the question?
* What is the average time it takes to mine a block? * If I choose a time uniformly what is the expected time it will take to mine that particular block. The difference between them being that blocks that take a long time occupy more space on the timeline than shorter blocks and are therefore more likely to be chosen.
How do you get this question from CyrusL's original question? CyrusL explicitly specifies that it is 10 minutes per block [0], and that he is uniformly picking a point in time.
[0] Admittedly, he does not specify that it is a Poisson distribution.
TLDR: Since blocks that take a long time to mine fill up more wall-clock time, if you pick an arbitrary instant of wall clock time, you're more likely to be in a "slow" block than a fast block. Specifically, you expect to wait 2x the average.
you expect to wait 2x the average.
The concept of memorylessness is not very intuitive, and thus from the true statements "average block time 10min" together with "the current instant is expected to be somewhere in the middle between two blocks" is drawn the wrong conclusion (disregarding memorylessness): "average wait time is 10/2 = 5min". So, new attempt at a tl;dr:
"you expect to wait 2x the intuitively (wrongly) expected time (of 5min)"
If you find the hash after say 6 minutes, you could delay broadcasting the block to the network for another minute or two, and give yourself an advantage.
Yes there’s a risk another miner would find the same hash, but statistically you could estimate the optimal delay for risk vs reward.