# Oracle Problem Explained
Blockchain smart contracts cannot directly access real-world or external data.
An oracle acts as a bridge between blockchain applications and external information such as prices, weather, or other off-chain data.
The main challenge is the Oracle Problem: how can a smart contract trust external data without depending on a single centralized source?
Centralized oracles can create risks such as manipulation, downtime, or a single point of failure.
Decentralized and verifiable oracle systems can reduce these risks by using multiple data sources and transparent verification.
Reliable data verification is important for building secure and trustworthy Web3 applications.