Ethereum: Why was the target block time chosen to be 10 minutes?

The Choice of 10 Minutes: A Tradeoff for Ethereum’s Network

In the world of cryptocurrency, block time refers to the interval between the creation of two consecutive blocks on the blockchain. In the case of Ethereum, the target block time is set at 15 seconds (not 10 minutes as mentioned in your question). But why was this choice made? According to various sources, including an interview with Vitalik Buterin, the creator of Ethereum, the 15-second block time was chosen as a tradeoff between two competing factors: propagation time and network stability.

Propagation Time: The Speed of New Blocks

In large networks like Ethereum’s, new blocks are created at a faster rate than they can be verified. This is because Ethereum uses a proof-of-work consensus algorithm that requires significant computational power to validate transactions. As a result, the block time for new blocks is not very long, allowing for rapid creation and propagation of new blocks.

The 15-second block time was chosen as a compromise between this fast propagation rate and the need for network stability. A shorter block time would mean faster creation of new blocks, but it would also increase the likelihood of network congestion and slowing down the blockchain’s overall performance.

Network Stability: The Importance of Synchronization

A longer block time would allow for more synchronization between nodes on the Ethereum network. With a 15-second block time, nodes can update their databases to reflect changes in the blockchain at a relatively rapid pace. However, this increased synchronization rate comes with additional overhead and potential stability issues.

A 10-minute block time would introduce significant delays between updates, making it more challenging for nodes to stay synchronized. This could lead to network congestion, decreased performance, and reduced security due to increased reliance on central nodes or centralized authorities.

The Verdict: A Balance is Maintained

In conclusion, the choice of a 15-second block time for Ethereum reflects a careful balance between two competing factors: propagation time and network stability. While a faster block time would have increased network congestion and decreased performance, it would also compromised node synchronization and security. The 10-minute tradeoff maintains a stable network while still allowing for rapid creation of new blocks in large networks.

As the creator of Ethereum, Vitalik Buterin has stated that the decision was made to “balance out” these competing factors, ensuring that the blockchain remains performant and secure despite its relatively fast propagation rate. This nuance highlights the complexities involved in designing a consensus algorithm like Ethereum, where tradeoffs are inherent to achieving a balance between competing requirements.