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What Is an Orphan Block?


An orphan block, in finance, refers to a block in the blockchain that has been verified and solved but is not accepted as part of the main chain. This usually happens when two different miners solve the same block simultaneously, leading to the creation of two potential blocks. The network decides which block is to be part of the main chain, leaving the other block “orphaned.”


The phonetic transcription of “What Is an Orphan Block?” is:/wɑːt ɪz æn ˈɔːrfən blɒk/

Key Takeaways


  1. An orphan block refers to a valid block on a blockchain that is not included in the final blockchain network. This happens due to simultaneous block discovery by miners, leading to temporary forks in the blockchain.
  2. Orphan blocks occur when two miners produce blocks at similar times, or when an attacker attempts to reverse a transaction. This is typically solved by the usage of consensus protocols, which decide on a version to continue with, leaving the other as the orphan block.
  3. Despite their name, orphan blocks are not without parents. They are simply blocks that are not included in the chosen chain. The miners who created the orphan block are not rewarded with mining rewards as they would have been if their block were chosen to be included in the chain.



An Orphan Block is a crucial concept in the world of cryptocurrencies and blockchain technology, primarily in the process of mining. It refers to a block of transactions that have been validated and solved by a miner but is not accepted into the blockchain network because another block with the same parent has been accepted faster. Hence, this valid but non-accepted block gets “orphaned.” Understanding this term is essential as it directly impacts the miner’s reward system, blockchain’s stability, and the security of the network. It can also influence the speed of transactions and can lead to potential issues such as double spending. Therefore, knowing about Orphan Blocks is vital for anyone involved in mining or investing in cryptocurrencies.


In the context of blockchain technology, which underpins cryptocurrencies like Bitcoin, an orphan block serves a rather interesting purpose. Essentially, an orphan block is a valid block on the blockchain network, but it is not included in the main chain of blocks. This usually occurs when two miners solve a block simultaneously. However, only one block can be added to the chain, and the block that gets added first becomes part of the blockchain while the other becomes an orphan block.Orphan blocks are not entirely discarded or wasted. The trends surrounding orphan blocks often help in understanding the state of a network, its congestion and the speed at which mining operations are being conducted. In a way, they contribute to the credibility of the network. Although transactions in an orphan block are not recognized on the blockchain, they are returned to the transaction pool and can be used in the future. Thus, orphan blocks help maintain the robustness and resilience of the blockchain network while ensuring no transaction is ever completely lost.


1. Bitcoin Mining: In the cryptocurrency world, Bitcoin miners often experience orphan blocks. These occur when two miners solve a block nearly simultaneously but due to slight differences in solving time, one block is incorporated into the blockchain, while the other is discarded or ‘orphaned’. The miner of the orphan block then loses the rewards associated with mining that block.2. Ethereum Blockchain: The creation of orphan blocks is quite common in the Ethereum blockchain network. During rapid transaction times, two miners may validate different blocks at the same time. Only one will be accepted onto the blockchain, leaving the other as an orphan block. Unlike Bitcoin, Ethereum actually provides a small reward for these otherwise discarded blocks, terming them as ‘uncle’ or ‘ommer’ blocks.3. Litecoin Scenario: Litecoin, like Bitcoin, is a cryptocurrency that can experience orphan blocks. For example, if two Litecoin miners solve the cryptographic puzzle for a block at the same time, the network may initially accept both blocks. However, as soon as the next block is added to the chain, the network will determine which of the two competing blocks is the official one based on the longest chain rule, leaving the other as an orphan block.

Frequently Asked Questions(FAQ)

What is an Orphan Block in finance and business term?

An Orphan Block is a block of data in a blockchain that is not included in the final chain of transactions. This happens when two miners solve a block at nearly the same time, leading to two potential blocks. Only one becomes part of the continuous chain, while the other is orphaned.

How does an Orphan Block occur?

Orphan Blocks occur when two miners produce blocks at similar times or when an attacker attempts to reverse a transaction. Only one can be part of the official chain, typically the one that gets recognized by the network first.

What happens to the transactions within an Orphan Block?

When a block becomes orphaned, its transactions generally go back into the mempool to be included in the next mined block. However, if a transaction is confirmed on the official chain before the next block, that transaction may not return to the mempool.

Is it possible to prevent Orphan Blocks?

It is impossible to eliminate the occurrence of Orphan Blocks completely. It’s simply a byproduct of a decentralized network where multiple people are adding blocks around the same time. However, through efficient mining strategies and network optimizations, the likelihood of their occurrence can be reduced.

Does an Orphan Block result in loss for the miner?

Yes, when a block is orphaned, the miner who solved it doesn’t get the block reward or transaction fees, as these go to whoever mined the block that becomes part of the blockchain. The valuable computations that the miner performed to solve the orphaned block become worthless. This is why Orphan Blocks are a risk that miners must take into consideration.

Related Finance Terms

  • Blockchain: A digital public ledger of all cryptocurrency transactions that have ever been executed.
  • Cryptocurrency: Digital or virtual currency that uses cryptography for security, commonly associated with a decentralized system (Blockchain)
  • Bitcoin: The first decentralized digital currency, created and stored electronically on the blockchain by an unknown person using the name Satoshi Nakamoto.
  • Miner: In cryptocurrency, miners are nodes in the network that process transactions and distribute them in the ledger, blockchain.
  • Hash: A function used in the blockchain that turns an input of letters and numbers into an encrypted output of a fixed length.

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