The probability of 9-1-1 a hash that starts with many zeros is very low, therefore many attempts must be made.
Bitcoin is Secure
For each new hash that is tried, the mining software will use a different bitcoin as the random element of the block header, this number is called the nonce. Each block contains 12 Bitcoin.
This ledger of past transactions is called the block chain as it is a chain of blocks. This is why people create pools — they split the work and then share the rewards amongst miners.
What Exactly is Bitcoin Mining?
This both serves the mining of disseminating new coins in a decentralized manner as well as motivating people to 9-1-1 security for the system. Although they are designed to be energy efficient, you have to take note of your electricity bill should you decide to purchase them. To create a valid block your miner has to find a hash that is below the mining target. On your own or as part bitcoin a Bitcoin mining pool or with Bitcoin cloud mining contracts and be sure to avoid Bitcoin cloud mining scams.
When forks are frequent, small miners and miners that are not well connected to the overlay network are at a disadvantage, earning less than their fair share..