What is UMA?

UMA's optimistic oracle is a decentralized truth machine. The oracle can verify any statement proposed on the blockchain. It provides real world data so smart contracts and markets asking for that data can be settled.
The project consists of the following major components working in conjunction:
Optimistic Oracle (OO): UMA's Optimistic Oracle allows contracts to quickly request and receive information. The OO provides that "real-world" data optimistically, which means that data is accepted as true unless anyone disputes the information.
Data Verification Mechanism (DVM): If a dispute is raised, a request is sent to the Data Verification Mechanism (DVM). Disputes sent to the DVM will be resolved after 48 hours after UMA token holders have voted to validate the off-chain data