Bitcoin Blockchain Reorganization on September 11
On September 11, Bitcoin underwent a minor blockchain reorganization, specifically at block height 966,500. This incident saw two competing blocks generated by different mining pools that were built on the same original block. While SpiderPool‘s block was initially recognized as the blockchain’s leading version after reaching a node operated by Galaxy Research, AntPool managed to create another valid block concurrently at that height. Eventually, AntPool’s block became the accepted part of the main chain.
Clarification on Network Functionality
It is important to clarify that this situation did not indicate any malfunction in the Bitcoin network; there were no bugs or successful attacks involved. In fact, such temporary competing blocks are a standard part of Bitcoin’s operations, even if the term “reorganization” can sound alarming.
Details of the Competing Blocks
According to information from Galaxy Research, the block produced by AntPool, which was deemed successful at height 966,500, had a timestamp of 11:30:30 UTC and included a total of 4,359 transactions. Although SpiderPool also created a valid block at the same height, Galaxy’s node acknowledged SpiderPool’s block first, resulting in a provisional position as the head of the blockchain from that perspective. This disparity occurs because not all Bitcoin nodes receive block information at the same time; thus, one miner could be working from a different block than another.
Understanding the Reorganization Process
Initially, Galaxy’s node was unaware of the existence of two versions of block 966,500 until AntPool produced the subsequent block, 966,501, that was built on its version. The protocol followed by Bitcoin nodes dictates that they accept the chain with the highest accumulated proof-of-work, leading Galaxy’s node to eventually disregard SpiderPool’s block in favor of AntPool’s.
Consequences of the Reorganization
The block generated by SpiderPool consequently became what is known as a stale or orphaned block, which effectively made the associated reward of approximately 3.1389 BTC unusable. In contrast, AntPool’s block yielded a reward of around 3.1411 BTC.
Historical Context of Reorganizations
Galaxy Research noted that this was not the first instance of a one-block reorganization this month, as two others had occurred earlier on August 16 at block height 962,722 and the second on August 24 at height 963,853. Similar to the recent incident, these earlier reorganizations involved competing blocks, but such occurrences are typically regarded as a normal part of Bitcoin’s blockchain dynamics.
