What Are Orphan Blocks?
In blockchain networks, orphan blocks are those that are mined almost simultaneously as another block but are not accepted by the blockchain. This happens primarily because there aren’t enough subsequent blocks attached to it for the network to recognize it as the longest chain. The Bitcoin blockchain discards such blocks, though other blockchains might leverage them differently.
Technically, these are known as stale blocks, but common terminology often refers to them as orphan blocks or uncle blocks.
Key Takeaways
- An orphan block is solved within the blockchain network but isn’t accepted by it.
- Occurs when two miners simultaneously solve valid blocks; the network uses both until one chain has more verified blocks. The orphan blocks are then discarded.
- Orphan blocks are a normal occurrence in distributed blockchains like Bitcoin.
Understanding Orphan Blocks
A blockchain comprises a series of blocks, each storing details of various transactions on the network. During standard mining processes, miners attempt to generate new blocks by solving the hash—a hexadecimal number containing the block’s information.
The first miner who successfully opens a new block is entitled to the block reward and writes the first transaction on this new block. The newly opened block also references the previous blocks and subsequent transactions, preparing the way for another block to be mined.
How Does a Block Become Orphaned?
The blocks in a blockchain form a parent-child relationship, passing on their data to the next in line. If two blocks originate from the same parent block at the same time, a fork occurs with two child blocks. Only one can integrate into the chain.
Network nodes, responsible for validating blocks, sort out which block to incorporate. This creates a temporary fork between the two children until a validation consensus is met.
Once validation consensus is achieved, the fork with the greater number of verified blocks—through proof of work (PoW)—gets accepted into the blockchain. Blocks in the shorter chain, including their children, become orphaned and put back into the memory pool.
Differentiating Orphan Blocks from Stale Blocks
Though people often refer to any rejected block as an orphan block, this isn’t technically accurate. An orphaned block implies it has no parent, while most discarded blocks have identifiable structures but are unaccepted by peer consensus, meaning they’re more accurately termed as stale blocks.
Blocks are organized in familial relationships for easy reference. A block without a parent would contain an incomplete block hash, and in a network relying on verification of all previous blocks, this occurrence would be highly irregular. Often, if a block is truly parentless, it may have been tampered with.
Common Misconceptions: Is Bitcoin a Block?
A block is a recorded ledger of transactions encrypted in the hash. Bitcoin, on the other hand, is the cryptocurrency rewarded for successfully solving the hash. Thus, Bitcoin is not a block but an incentivizing reward for block creation.
What Happens to Orphaned Bitcoin?
Bitcoin can’t become orphaned. Rather, it’s the blocks that may end up as orphans and are subsequently discarded.
Mining Rewards: Are Orphan Blocks Valued?
Typically, mining orphan (or rather stale) blocks doesn’t result in any reward. However, certain blockchains might have exceptions, offering rewards even for mining stale blocks.
Always remember, investing in cryptocurrencies is highly risky and speculative. Consulting a qualified professional is advised before making any financial decisions.
Related Terms: blockchain, stale block, proof of work, orphaned Bitcoin, block hash
References
- Oracle. “Using Parent-Child References”.
- Gemini. “How a Block in the Bitcoin Blockchain Works”.
