The Merge

The Merge fused Ethereum's original execution chain, until then proof of work, with the proof-of-stake Beacon Chain that had been running since 1 December 2020. It happened in two steps. Bellatrix, on the consensus layer, activated on 6 September 2022 and prepared the Beacon Chain. Paris, on the execution layer, triggered upon reaching the Terminal Total Difficulty on 15 September 2022 around 06:42 UTC, the moment the merge completed. After it, blocks are proposed by validators who have deposited 32 ETH in staking, and mining disappeared.

It cut Ethereum's energy consumption by roughly 99.95% and changed the economics of those who secure the network, from miners to stakers. The issuance of new ETH fell sharply, around 90%, and finality came to be determined by checkpoints with Casper FFG every two epochs, about 12.8 minutes, rather than being purely probabilistic. It is a key milestone for placing in context the current consensus of the second most-used network in tokenization and decentralized finance.