Hello I am a student who is trying to understand bitcoin mining and block chain technology. As I read the articles and papers about bitcoin mining, mining is the process of adding transaction records to Bitcoin's public ledger of past transactions. And its average solving time is around 10 minutes and whoever solve the fastest will be awarded to 25 BTC. So if there are more and more people using bitcoin and sending their bitcoin to each other, then more and more bitcoin has to be awarded to whoever solved it right? Is that why the predicted time for last Bitcoin to be mined is becoming sooner and sooner? If Bitcoin becomes a major currency and millions and millions of people use bitcoin everyday then are there any possibility that the last bitcoin will be mined way sooner than expected date which is May 7th, 2140? Thank you
Mining is the process of extenting the chain with new blocks containing (or not) new transactions. The block reward and any tx fees for that block goes to the miner, who found a nonce such that the hash meets that block's difficulty target. In Bitcoin the difficulty retargets every couple weeks I believe. This means that if more miners start mining, they will indeed cause blocks to be found faster than the 10 minute starget on average, until difficulty retargets, where it will go back to about 10 minutes (and possibly go up or down depending on whther new miners arrive, or existing miners leave).
Due to thus two weeks retargetting, there should be only minimal change to the expected time of the last block reward (accumulation of each two weeks period's drifts).
Last, the number of txes do not influence the number of blocks. The miner does get a bit more due to the tx fees, but whether blocks are full or empty or the the middle, the target is still 10 minutes.
As more hashing power is put towards mining, the faster a block is solved. Every 2,016 blocks, the difficulty of mining a block is re-targeted so that on average, blocks will still be found every 10 minutes. This means that it will be roughly every 14 days (
((10 minutes * 2,016 blocks) / 60 minutes per hour) / 24 hours per day = 14 days).
However, when the hashing power of the network over time is sloping upwards, this means that there is a 14 day lag before recalculation. As the hashing power increases over these 14 days, blocks are mined less than 10 minutes on average, thus bringing the date of the last mined coin sooner than predicted.
However, the opposite happens if hashing power is trending downward. During the 14 day period, blocks will start to take greater than 10 minutes, thus pushing back the date of the last mined coin.
Seeing as we are only 7 years in, out of a 131 year time span, it's hard to predict whether hashing power will slope upwards more than it will slope downwards during the next century or so. If it slopes more upwards than down, then all coins will be mined prior to 2140. If it slopes more downwards than up, then we may still have coins to mine after 2140. We all expect it to slope upwards, but there is probably a limit at which point it never goes much higher, and may even trend downwards.
I think it is far too soon to predict an actual date.