Why is it so difficult to mine if nounce is not more than 4 billion?

Question

bitcoin

I looked at the block explorer and saw a pattern that the number of nounce is not more than 4,000,000,000?

Looking at the blocks, I noticed a large number between 2 and 3.5 billion, my card will probably give out about 40 mega hashes, which is 100 seconds and I can iterate through all 4,000,000,000 nounce values

​​I don’t know something or is there another parameter that can be in the block change besides nounce?

Answer 1

I would venture to guess that the fact is that processing a block with one nonce requires a lot of hashing operations. SHA-256 "eats" 512 bits at a time, and the block size is about a megabyte. Plus, in BTC, a double SHA-256(SHA-256(Data)) hash is considered.
But even taking into account all this, the figures do not converge somewhere by 2-3 orders of magnitude.
UPD. Found. In addition to the nonce, the block also includes a timestamp . It can be changed within fairly large limits without violating the validity of the block (it must be greater than the median time of the previous 11 blocks and less than the average network time +2 hours). Having driven the entire nonce range and not getting a beautiful hash, the miner slightly changes the timestamp and runs the entire nonce range again. And then again and again until it hits.
The entire range of valid timestamps is almost 3 hours ~10^4 seconds. Now it seems to fit.

Answer 2

In addition to Nonce, nTime is also spinning, plus the block template periodically changes, because transactions with tasty commissions are thrown, and some others fly out. I also recommend extraNonce to google. Any change causes a hash change, so everyone has enough.