Crypto Orphans: Valid Blocks Without a Chain

Orphan is an active block on the blockchain that is not part of the main chain.

What is orphan?

Orphan is a legitimate block that is not part of the main blockchain. It is also called an obsolete or orphan block. There are various factors that can cause orphaned blocks to appear. The main ones include Internet latency, the length of the blockchain, the size of the block and the speed of the node hosting the blockchain. Under the influence of these factors, two blocks may have the same timestamp, causing the underlying blockchain to reject one block and absorb the other.

A timestamp can occur in a situation where, for example, two miners in a Bitcoin blockchain simultaneously find, resolve and distribute a block. As a result of the above factors, the two blocks see different nodes at different times.

As new blocks emerge, nodes will add them to the chain they believe to be valid. In the Bitcoin blockchain, the longer chain is automatically assumed to be valid. Thus, one of the two blocks, despite its accuracy, will be orphaned (the shorter chain).

But blockchain developers reduce the probability of orphans by taking into account propagation delay and block time. The probability of orphaning is high if the decentralized platform has a high propagation delay and short block time.

It should be noted that too many competing blocks can also lead to forks, hence competing chains. Such chains lead to instability or jamming of decentralized networks.