The inter-play between bitcoin’s hashrate and difficulty has seemingly led to considerable block time volatility in the past 24 hours.
According to Coin Dance data, there was no block at all in an entire one hour period and that seems to have occurred twice.
We can see above there was no block 22 hours ago, nor 24 hours ago, with just one block found in a two hours long period.
On the other hand, two hours ago there were some 10 blocks found in just a one hour period with block times seemingly all over the place.
This considerable variation is probably because the bitcoin hashrate is seeing a lot of up and down allegedly due to the coming to an end of the rainy season in China.
That’s where bitcoin mining is concentrated and usually they tend to rely on hydraulic power because cheap and renewable.
So when there is more rain, electricity is cheaper, and thus mining a bitcoin costs less and so is more profitable.
As we can see above, bitcoin’s hashrate plunged recently some 30% as miners presumably turned off their gear due to electricity no longer being as cheap.
However, hash then spikes to an all time high of 110 quintillion, but it doesn’t stay there long as it falls again about 30% to 80 quintillion.
While all this yoyoing is going on here, difficulty has known only one direction: up and up.
Since January 2019, the ladder has moved to reach some 12.75 trillion with it increasing on the 27th of September.
That’s just a day after hash all-time highed, with it unclear actually whether miners are trying to game the difficulty or whether this was just a coincidence.
One might think the latter because presumably it would not be in miners’ interest for the difficulty to be higher than the hash, but 70 to 110 to 80 is a bit all over the place.
In any event, since difficulty is at a network hash of 110, while the actual hash is at 80, you’d expect blocks to be slow, although not two hours slow.
We had here however 10 blocks in an hour, and more importantly what we might have is one person/entity in control of 40 quintillion, about 40% of the bitcoin hash.
If that’s the case, they can take off the hash and slow down the network, then turn it on again and speed it up.
Especially around difficulty changes they could take off the hash and so allow difficulty to drop, and turn it on to speed up the network sort of to the power of 2.
Maybe that’s what they tried to do the first time around, but the drop got quite a bit of media attention, so to assure they might have turned it back on, leading to the opposite of a difficulty drop.
Now mining is a bit more difficult than usual, so miners at the edge of cost/profit might be struggling, which may benefit this miner as he might have less competition.
Yet whether there is actually any playing going on, is not clear. To have a better idea, we’d need to undertake analysis of nounces and so on, which we don’t have the resources to do so are not in a position to conclude whether this hash does belong to one person/entity.
If it is the case, it would be a reason to keep an eye on it, but not really reason for significant concern.
That’s because mining gear keeps improving with asics speeding up constantly, so any such hash share would be just temporary.
In addition, there isn’t much they can do with it except for potentially double spending their own bitcoin. That would be noticed, however, and probably quickly, with different measures available in response, including DDoS-ing the hash/pool or changing the algo completely.
Yet if it’s bitcoin coders playing with new found hash, it can get quite a bit more complicated as then it might be a matter for miners to outplay each other.
For now however there is no indication of anything significantly unusual, so we’ll have to wait and see if there is anything here or just variation.