Bitcoin (BTC) is digital money that can be sent over the internet without a bank. It was launched in 2009 by an unknown creator called Satoshi Nakamoto. Bitcoin runs on a blockchain, a public record that tracks transactions and helps keep the system secure. Only 21 million BTC will ever exist, so many people call it “digital gold.” People use Bitcoin to invest, trade, and send money worldwide, but its price can rise or fall quickly, so it carries risk.