1. A computer system for a prediction market, comprising: a processor device performing as a prediction market engine providing services to support prediction markets aggregating information about orders placed on a continuous interval of a continuous outcome space by performing steps of: receiving a plurality of orders from a plurality of traders, each order specifying a non-empty open continuous interval of the continuous outcome space; determining prices of the orders to accept using a payout function of a continuous-outcome dynamic pari-mutuel market; transmitting information to traders in the prediction market, said information comprising the quantities and the prices of the orders; collecting amounts owed for the orders accepted by the traders; identifying winning accepted orders; determining winning amounts; and paying out the winning amounts for the accepted orders; and a storage operably coupled to the processor device storing the orders placed on the continuous intervals of the continuous outcome space.