What Is a Blockchain?
Imagine a ledger copied across thousands of computers. Each new batch of transactions is a block, cryptographically linked to the previous one — forming a chain. Changing old data would require redoing all subsequent blocks across the network, which is practically impossible.
How Consensus Works
Networks use consensus mechanisms to agree on the ledger. Proof of Work (Bitcoin) uses computation; Proof of Stake (Ethereum, Solana) uses staked tokens. Solana adds Proof of History for speed — see What Is Solana.
Why Blockchains Matter
- Trustless: no central authority required.
- Transparent: anyone can verify.
- Programmable: smart contracts enable DeFi.
What Runs on Blockchains?
Beyond payments, blockchains power DeFi (like Jupiter), NFTs, DePIN, and more. Solana's speed makes it ideal for high-frequency applications.
Summary
A blockchain is a decentralized ledger that chains blocks of transactions together and uses consensus to stay trustworthy without a central authority. This design unlocks transparent, programmable money — the basis for everything from Bitcoin to Solana DeFi apps like Jupiter.
Frequently Asked Questions
Can blockchain data be changed?
Practically no. Altering confirmed data would require overpowering the entire network's consensus, which is infeasible on established chains.
What makes Solana's blockchain fast?
Solana combines Proof of History with Proof of Stake and parallel execution to achieve sub-second blocks and very low fees.