# Definition of orphan block (cryptocurrency)

By Mark Holland / last week

## What is an orphan block?

In terms of cryptocurrencies, orphan blocks, sometimes referred to as stale blocks, are blocks that are not accepted on the blockchain network due to a delay in reporting the block in question (compared to a qualified block) to the network of miners. .

Orphan blocks are technically valid and verified blocks, but they have been rejected by the chain. They are also called separate blocks, as they exist in isolation from the blockchain.

### Key takeaways

• An orphan block is a block that has been resolved within the blockchain network but was not accepted due to a delay within the network itself.
• There can be two miners solving a block simultaneously. The miner who has a more detailed proof-of-work sheet is the one who receives the block reward.
• There is no reward for solving a block that is later determined to be an orphan block.

## Understanding an orphan block

A blockchain consists of a series of blocks, which act as data storage units to store details of the various transactions that occur on the blockchain network. During the standard mining process, miners attempt to generate new blocks by solving the complex mathematical equations necessary for the blockchain network to function.

The first miner who is successful in finding a new block is entitled to the block reward and writes the first transaction to the new block he found. In order for the blockchain network to continue to function, the newly found block is added as the new ‘unit’ on the blockchain.

However, it is possible for two miners to produce a block at the same time. This situation occurs because the acceptance of the blocks in the blockchain by the nodes of the blockchain network does not happen instantly.

This delay in accepting a block can lead to another miner solving the exact same block. It leads to temporary confusion in the blockchain network, as the nodes try to decide which block of the two newly identified blocks they want to accept.

In such a situation, the block with the highest Proof of Work (PoW) ratio is accepted on the blockchain. The other block, with a smaller proof of work, is discarded from being added to the blockchain and is called an orphan block. Such blocks are essentially valid and verified blocks, but due to the working mechanism of the network and the delay time leading to delayed acceptance, one of the blocks is rejected or orphaned.

Another way an orphan block is created is when a hacker with sufficient hashing power tries to reverse some transactions that previously occurred on the blockchain network.

Orphan blocks are usually linked to the popular cryptocurrency network Bitcoin. In the case of a valid transaction existing in an orphan block, it is appended to the next valid accepted block in the blockchain.

## Special Considerations: Orphan Block Rewards

Although it may seem that the blockchain miner responsible for producing an orphan block should be compensated for his time and energy, in fact, he does not receive any reward for solving the block and producing an orphan block.

There are many miners who consider this practice unfair, as they are not compensated in any way for producing exceptional work that is only not accepted because there was a delay in the blockchain acceptance network.

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