# Is it true that the rate of finding a new block is constant, but just that the bitcoin reward become less and less? [duplicate]

Can somebody ELI5? Is it true that every block that is discovered, the person that discovered the block will be awarded 12.5 bitcoins? But to discover such a block, somehow the person has to get a SHA256 number that has all 0's for the first 72 bits?

What if somehow, in that 10 minutes, two new blocks are discovered, or likewise, what if a new block took 20 minutes to be discovered?

And it is 10 minutes per block discovered? So in the year 2022, when the number of bitcoin awarded is halved again, to 6.25 bitcoins, does that mean it is still 10 minutes per block, but now the award is 6.25 bitcoins?

Or does the 72 of 0 bits now become 73 of 0 bits?

So is it true that even in year 2140, when all 21 million bitcoins have been rewarded, then new blocks will still come out every 10 miniutes, and good for recording transactions?

It is said that 1 block is 1MB, and each transaction is about 0.25kb, so 1 block = 1MB, is good for 4000 transactions. So in year 2035, or in year 2140, we can still record new transaction at a rate of 4000 transaction per 10 minutes?

• Does this answer your question? What exactly is Mining? and What keeps the average block time at 10 minutes? Jan 30 '21 at 17:22
• @RedGrittyBrick do those answers talk about 72 bits of 0's? Jan 30 '21 at 17:31
• 72 bits of 0s is not a special number overall. You are talking about a difficulty level which is readjusted every 2016 blocks based on prior 2015 block times. At some time the difficulty level might be a number that has some specific number of leading zeros at other times it will be different. It effectively adjusts depending on the combined total hashing power (total hashrate) of miners. It is adjusted to whatever number would be sufficient to keep the block production rate near 10 mins. This is explained in answers to the linked questions. Jan 30 '21 at 17:37
• P.S. to attract better answers, you can try to ask only one question at a time (I count eight question marks in your question above). This is explained in the help center Jan 30 '21 at 17:41
• Also the blocksize is not 1 MB: bitcoin.stackexchange.com/a/101788 Jan 30 '21 at 17:53