Mining

Mining is how proof-of-work blockchains like Bitcoin create new blocks and new coins. Miners collect pending transactions, assemble them into a candidate block, and then race to find a number that makes the block's hash fall below a target. The search is pure trial and error, requiring trillions of attempts per second. The first miner to succeed broadcasts the block and collects the reward.

Early Bitcoin mining ran on ordinary laptops. Today it requires specialized chips called ASICs housed in warehouses with cheap electricity and industrial cooling. Large public companies such as Marathon and Riot operate hundreds of thousands of machines. Most individual miners join pools that combine hash power and share rewards in proportion to work contributed.

Bitcoin mining's energy use, in the range of a mid-sized country, is its most debated feature. Supporters note that a growing share comes from stranded or renewable energy and that mining can stabilize power grids by shutting down during peaks. Ethereum ended mining in September 2022 by switching to proof of stake.