Orphaned Block

Understanding the Concept of Orphaned Blocks

An orphaned block is a block that does not have a parent block or its parent is unknown. In earlier versions of the Bitcoin core software, these blocks were commonly seen, as network nodes could receive blocks without information about their ancestors.

However, with the release of Bitcoin Core v.0.10 in early 2015, the occurrence of orphaned blocks became impossible.

Nevertheless, the term “orphaned block” is still used in the cryptocurrency world to describe valid blocks that have been discarded. These blocks are sometimes called stale or extinct blocks. However, they are commonly known as orphaned blocks because the client labels them as such. It is important to understand the difference between orphaned blocks and stale blocks.

An orphaned block is created when two different miners simultaneously transmit their valid blocks, causing the network to split into competing versions of the blockchain. Eventually, one of the blocks is discarded, and the longest chain becomes the prevailing one. Although both blocks are valid, only one can be attached to the main chain.

Since miners continuously generate new blocks, it is possible for certain blocks to be broadcasted at the same time. However, due to the distributed nature of the network, the transmission of this information between nodes can be time-consuming. As a result, one group of nodes may validate one block while another group validates a different block. This discrepancy leads to one of the blocks being orphaned.