What is Bitcoin?
Answer
Bitcoin (BTC) is the world's first and largest cryptocurrency, created by the pseudonymous Satoshi Nakamoto in 2008 (whitepaper) and launched in January 2009. Key facts: (1) Fixed supply — maximum 21 million BTC will ever exist (currently ~19.7M mined); the finite supply is enforced by the protocol; (2) Halving — every ~4 years, the mining reward halves (currently 3.125 BTC per block after April 2024 halving); (3) Proof of Work — uses SHA-256 mining; energy-intensive but battle-tested; (4) 10-minute blocks — designed for ~10 minutes between blocks; (5) UTXO model — tracks unspent transaction outputs rather than account balances; (6) Limited programmability — Bitcoin Script is intentionally simple for security; not Turing-complete; (7) Lightning Network — Layer 2 scaling solution for fast, cheap Bitcoin payments. Bitcoin is primarily viewed as a store of value ("digital gold") and hedge against inflation, not a general-purpose computational platform.