Ethereum is one of the best-known blockchains, a shared record of transactions kept by thousands of computers rather than by one company. On 15 September 2022 it completed "the Merge", a major upgrade that changed how those computers reach agreement.
From proof of work to proof of stake
Until then, Ethereum used proof of work: computers competed to solve difficult puzzles, which used a great deal of electricity. After the Merge, it uses proof of stake: participants lock up coins as a deposit and are chosen to confirm transactions, and they can lose the deposit if they cheat. The Ethereum Foundation reported that this reduced the network's energy use by more than 99 percent.
What it shows
- Large systems can be changed while running. The upgrade was tested for a long time before the switch.
- Energy matters in computing. Every design choice has a cost, and engineers can reduce it.
- Not everything with "crypto" in its name is the same. Prices rise and fall sharply and scams are common, so young people should treat cryptocurrencies with caution.
For learners, blockchain is a good example of how ideas from mathematics, networking and economics combine in one piece of technology.