Topic: Is it possible to mine all BTC before 2140? (Read 3201 times)

You have 3 mistakes here:

1. The difficulty adjusts every 2016 blocks, not every 2 weeks. It may sound the same but they are definitely completely different concepts.

2. Difficulty will never adjust by more than 4x, for both upward and downward

3. The difficulty will never go below 1

0. Highly unlikely.
1. For all intents and purposes, impossible, not even a majority.
2. For all intents and purposes, because of 1, impossible.
3. Won't happen, because 2 won't happen.
4. With such a low difficulty, someone will attempt this.

Go back to sleep.


In order for 1 to happen, you have to forcefully destroy those miners, or forcefully disconnect them from the internet. We will have other problems when that happens.

Sorry no, if your mother is looking for someone to arrange a playdate with, try the newbie section.

Your words, not mine.

Are you 12 or younger? Your manner of snark reminds me of my 12 year old neighbor.

Right so if there's a fractional reserve exchange, with say 800,000 BTC that don't really exist, and things go south, people can lose money, how insightful.

What's the price? The last BTC sold/bought on an exchange?

When demand goes down what happens? Support for current price disappears.

When there's no support and everyone tries to sell all at once in a race to fill whatever bids are left after everyone pulled out their buy orders... what happens? Catastrophic crash into 0, or the lowest order that was on there by the time they're all matched up and no one wants to buy anymore.

explain how people are panic selling? hmm, ok, maybe the same reason Gox was able to steal so much of their users' money. BECAUSE A LOT OF TRADERS HOLD A LIQUIDITY POOL OF BTC ON EXCHANGES SO THEY CAN EASILY GO IN AND OUT BETWEEN EXCHANGES AND TRADE. You know, because traders tend to like to trade, you know.

When your BTC is just a number on an exchange's database, you most certainly can sell your BTC, sir...

so I guess tl;dr: E = MC^2  

Okay Einstein, explain to me exactly how people are panic selling all their bitcoins when blocks are not being made.

Also, if there is a seller, there is a buyer. Someone who values those coins higher than the seller does.

Game theory.

Ok, let's say you were able to get EVERY SINGLE HASH OF POWER to cooperate and stop mining at a specific time....

Everyone would sell their bitcoins because blocks would not confirm while you were doing this, AND showing all miners cooperating removes trust of the network... ie. if they can coordinate THIS, then WHAT ELSE could they coordinate? (Think of some alt coins that had "cooperation" from the miners to "roll back" blocks. And see where THAT got them... lol)

But in reality, it would never happen. Everyone knows that the only way they can win is by continuing to mine.

Go and promote your other rubbish-coins in the alt-coin subforum. This is technical discussion post.



As other have noted, the difficulty retargets every 2016 blocks to a level which should give you ~10 minute blocks at current hash rate. This has the effect of retargeting difficulty *roughly* every two weeks. The "final mint date" has been extrapolated from there to about 2140, this shoudl be relatively accurate.

There is also a hardcoded minimum and maximum retarget amount (400%), this prohibits the addition/withdrawal of a signifcant amount of hashing power causing a sever difficulty retarget. wihtout this a malicious actor could add say 30% of network has rate for 2 weeks, then after the retarget withdraw it all, leaving blocks going unsolved for (unnaceptably) long periods of time. The reverse is also possible where a large amount of hashign power would suddenly be added and blocks would confirm extremely fast.

As has already been said, while the network size increases, blocks are found faster until the retargetting that happens every 2016 blocks so it is always faster than the 2 weeks during growth. However there is also an upper limit on how much the diff can rise - a 400% rise max as a sanity check is built into the system. If for example, a technology revolution brought about some massive increase in efficiency that made for more than 4x increases in the network speed, it would grow much faster than difficulty rises could keep up with accelerating it far more than just 4x the block solve speed. The more the rise is over 400% the faster the bitcoin will be found/depleted.

So for example if the network hashrate were to rise 400% between every block change, the remaining blocks would be found in an inversely proportionately faster rate of 1/4 of the time - the relationship is linear even though the network growth is exponential. If the network hashrate always grew more than 400%, then the more the growth is over 400%, the closer the block finding speed becomes to an exponential function itself. Of course this all assumes exponential growth in hashrate which, barring some technology revolution, is impossible to maintain.

Answering the original question...

Bitcoins are mined faster than scheduled when the difficulty rises and slower than scheduled when the difficulty falls because of the way the difficulty is calculated. If the difficulty continues to rise, the remaining bitcoins will be mined many years ahead of schedule.

Your exploit won't work because the difficulty is recalculated every 2016 blocks, not every two weeks.

I don't think so. I could be wrong though

Yes dammit, get my brain in the wrong groove and say silly shit... take "most" of the hash off, and what was left on would still be chugging away 2 weeks later, probably only a couple hundred blocks done, and block times for that period being hours. Drastic, long term hash drop, would take a very long time to reconcile diff with current hashrate.


and yah, I meant 2139 or 2138

Yes, looks like I was wrong about the block reward decreasing exponentially forever like an asymptote. Technically, it depends upon the rate of difficulty increasing during the last 2 weeks as to whether it will be reached shortly after 2140 or never reached:

https://en.bitcoin.it/wiki/Controlled_supply

If difficulty isn't exploding during those last 2 weeks than 21 million will never be reached and only ~20999999.97690000 will be minted.

This is not true. The block subsidy will automatically change based on the number of blocks mined and once the number of blocks mined is equal to an amount that causes the total number of bitcoin ever mined to be 21 million then the block subsidy will change to 0 (I forget which block this will be on).

@OP - it is a common misconception that the difficulty will change every two weeks, as this is not correct. The difficulty will change every 2016 blocks to a difficulty that would have caused the previous 2016 blocks to be mined in exactly 2 weeks if the difficulty was what it is going to be changed to. As a result if all the miners were to stop mining then no new blocks would be created so it would not be possible to ever get to the next difficulty retarget.

To answer the question in the title of your post, yes all bitcoin will almost certainly be mined prior to the year 2140 as the difficulty has increased so much that each 2016 set of blocks has, on average been mined in much less then every two weeks. 

just over 20 million will be mined in 15 years not 120 years. after 15 years, then its like 110 years of very little reward per block. so no one will really care about the reward
math:
2017=15.75
2021=18.375
2025=19.6875
2029=20.343

You mean 2139?
I'm not sure that the cap will ever be reached though. I'm not sure why people are thinking about this now. Nobody who is alive now, will see that day anyway.

Unlikely the 21 million cap will ever be 'reached'. It can be approached, but it is designed as an asymptote that is never reached. In the unlikely even that your scenario happens in the last 2 weeks leading up to 2140 the 21 million cap could technically be slightly surpassed though.

Wellll, during periods of high hashrate increase there is some shorting of the times, we might end up at the last coin in 2039 or 2038.

I think there would be problems if diff somehow got set to zero and then all current hash came back on again, too many blocks too fast, I think there would be lots of forks since they wouldn't propagate as fast as they were being made. In fact, I'd recommend the devs have a contingency plan to manually set difficulty, if some event like a huge solar flare were to happen and knock out a lot of power grids and comms, would probably be 75% survival rate for electronics, with the infrastructure being off for a couple of weeks being the larger problem.

Edit: I answered the thread topic, not the op's scenario. My bad.... 

Yes, it will be sooner than originally predicted. The problem is hashpower gets added after the calculation is made each time at the 2016 block mark. That's why we are ahead of schedule and it takes less than 14 days most of the time to reach 2016 blocks.

Note: It isn't so much that the amount of hashrate added is excessive (although there is a limit to how much the difficulty can increase - 400% every 2016 blocks), it is that the additional hashrate is not all added at the same time. Say for example that when the difficulty changes, exactly 10% additional hashrate is added to the network then at 1008 blocks after he difficulty changes, an additional 10% of hashpower is added to the network (off of the original hashrate) (and no variances in luck and no other changes to mining power) then by 2016 blocks after the previous difficulty change, the difficulty will be 15% higher but the hashrate will be 20% higher.


This is the block chain's control theory feedback loop:

60minhr∗24hrday∗7dayweek 10minblock=2016 in 2weeks

Tcurrent=Tprior∗tprior/2weeks

D=work/2(32)=2(256)/(Tcurrent+1)∗2(32)

hashes/second≈D∗2(32)/600

The current target for the block chain is determined by a calculation, so any two clients looking at the block chain will calculate the same target. This calculation aims to adjust the target such that one block will be mined every 10 minutes, no matter how much total computing power is devoted to mining. The target changes every 2016 blocks based on the timestamps within those blocks. Why 2016? Because Satoshi decided two weeks was a good interval, and at 10 minutes per block, 2016 blocks will be mined every two weeks.

When 2016 blocks take more than two weeks to mine, the target goes up to make mining easier; when they take less than two weeks, the target goes down to make mining harder. In symbols, if Tprior is the previous target and tprior is the time it took to mine 2016 blocks using that target, then the updated target Tcurrent is just.

The target is typically a huge number well in excess of 2(200). Also it goes down as the total hashing power of the miners goes up. Consequently, interested people usually think in terms of the difficulty instead. Definition: The Bitcoin difficulty is the average number of nonces you have to try to find a valid block — aka. the work — divided by 2(32)(roughly 4 billion).

Note that D is just a number for human consumption. It scales in direct proportion to the computational effort required for mining, so twice the difficulty means twice the effort.

If we know the current difficulty D, we can estimate how fast all miners are hashing in aggregate. On average, it takes D∗2(32) hashes to find a nonce that works, and the target is selected to make that take 10 minutes.