Bitcoin Forum

I don't understand how if miners are constantly guessing a nonce that is together with the tx list of their potential block, prev tx hash, etc, a solution that must be constantly changing whenever they add a tx to their potential block. I can see that once a block is full, it makes sense in my head to now start guessing the nonce to combine with the current list of txs hash, however if blocks are not filling up, it just makes no sense to me how miners decide when to guess a nonce that includes the list of txs they picked up…surely they need a static list of txs in order to make guessing effective? Thank you in advance!

Miners are trying to find the nonce just as the last block has been created.
There is no problem in instantly finding a nonce, and creating a block with zero transactions inside (the only downside would be to lose the transaction fees, but it is worth anyway, because they will win the 12.5 btc for creating a block).

I wrote about this in more detail in this thread
 summary on Proof of Work (https://bitcointalk.org/index.php?topic=3317586.msg34646752#msg34646752)


Miners are trying to find nonce at an absurd rate of hashes per second. They are updating their candidate block with the mempool at every second, and using their hashing power to find the nonce everytime. Every second counts. They are literally running to find the nonce and create the block, no matter how many transactions are on the mempool. It makes almost no difference for them, because the reward for finding the block is enormous.

There is no right answer for a valid nonce, it's completely random. So mathematically speaking it doesn't matter if you're constantly rebuilding your blocks and starting to guess nonces all over again for a brand new block.