Bitcoin miners found two blocks; one was orphaned

Two miners or mining pools on the Bitcoin network produced valid blocks at the same block height after near-simultaneous discoveries. The network briefly split as different nodes accepted different blocks; when the split resolved, one block was orphaned and removed from the accepted chain.

Near-simultaneous block discovery and differences in how blocks propagate across the peer-to-peer network caused nodes in different regions to build on different blocks, creating a short-lived fork. Bitcoin clients follow the chain with the most cumulative proof-of-work, so when a new block extended one competing chain, the protocol treated that longer chain as authoritative.

An orphaned block, also called a stale block, contains valid transactions and a valid proof-of-work but is not part of the canonical ledger. The miner of an orphaned block does not receive the block subsidy or transaction fees on the main chain. If the miner participated in a mining pool, payouts depend on the pool’s reward rules and the pool may absorb or redistribute the loss.

Transactions included only in the orphaned block are returned to the mempool and await inclusion in a future block. Transactions that appeared in both competing blocks keep their confirmations once they appear on the accepted chain. Confirmations provided by the orphaned block are removed, and wallets and services will show a reduced confirmation count until those transactions are re-mined.

Short forks from simultaneous block discoveries are an expected part of a decentralized network and are usually resolved within minutes by following the longest, most-work chain. Factors such as network propagation speed, the geographic distribution of miners and slight differences in block arrival times contribute to these temporary splits. Reorganizations that affect multiple blocks are rare.

After the network converges on a single chain there is no change to the ledger. The event can briefly affect transaction confirmation times and the immediate income of the miner whose block was orphaned. Miners and pools monitor orphan rates and incorporate the risk into pool design and payout formulas.