What is Bitcoin?

Bitcoin (BTC) is the first and best-known cryptocurrency — a form of digital money that runs on the internet with no bank, company, or government in charge of it. It was created in 2009 by an anonymous person (or group) using the name Satoshi Nakamoto.

How does it work?

Instead of a bank keeping the master list of who owns what, Bitcoin uses a shared public ledger called a blockchain — a record that thousands of computers worldwide hold copies of and constantly agree on. When you send Bitcoin, that transaction is added to the ledger and confirmed by the network, so no single party can secretly change it or spend the same coin twice.

Why is it limited?

There will only ever be 21 million Bitcoin. New coins are released slowly to the computers ("miners") that process transactions, and that rate halves roughly every four years. That fixed supply is why people compare Bitcoin to "digital gold" — you can't simply print more.

Why do people care — and what's the risk?

Supporters like that it's borderless, scarce, and not controlled by one authority. Critics point to its price swings and energy use. Bitcoin's price can move sharply in either direction in a single day, so it's widely treated as a high-risk, speculative asset — never money you can't afford to lose.