Defining an Orphaned Block
An orphaned block is a block whose parent block either doesn’t exist or isn’t known.
This scenario of creating orphaned blocks was observed in older versions of the Bitcoin core software.
In these older versions, network nodes could receive blocks even if they had no information about the blocks’ parent. However, since the release of Bitcoin Core v.0.10 in early 2015, the generation of Bitcoin orphaned blocks has been eliminated.
Orphaned Blocks in Cryptocurrency
Despite the above, the term “orphaned block” continues to be used within the cryptocurrency sphere, but it typically refers to valid blocks that have been cast aside.
These abandoned blocks may also be termed stale blocks or extinct blocks.
Still, many refer to them as orphaned blocks because the software marks their block rewards as orphaned.
Even though these blocks have a known parent block, they are often called orphaned blocks instead of stale blocks.
However, it’s essential to understand the distinction between the two.
Unraveling Orphaned Blocks
Eventually, one of the blocks gets discarded while the longer chain persists as per the general rule.
Even though both blocks have been validated and are legitimate, only one can be added to the main chain.
Parallel Propagation and Consensus
Since miners continually produce new blocks, certain blocks may be propagated onto the network simultaneously.
Considering the network’s distributed nature, transmitting this data between nodes could take a significant amount of time.
Consequently, some nodes may choose to validate one block, while others may select a different one.
Ultimately, the nodes reach a consensus on which block to accept. This process can lead to the orphaning of one of the blocks.