What is the reason for the timestamp field in the block header? Surely the nonce should be the only property that changes? Should the nonce reset to 0 everytime the timestamp changes?
the timestamp is very important to authenticate when the block was created and also it has various functions to mempool and the nonce . just for little deep knowledge of time stamp :- 1- the timestamp refreshes every 1 second and in that 1 second the nonce should be able to find the golden nonce which is approx around 0-4 Billion iterations within the sec. which seems impossible .
2- it's impossible but it can be possible for the people minning together they can use their combined computational power to solve the 0-4 billion iterations within less than second which then the hash could be gained and the block is given to them with fee associated to it
and lastly the nonce do changes every time when the timestamp changes within 1 second