smart contracts cannot make use of information from the outside world (unless of course, fed from a single centralized party).
There has been some work on taking the median of multiple oracles, requiring oracles to post collateral that will be forfeited if they disagree too much with the others, and using attested hardware (SGX) to make oracles more auditable.
There has been some work on taking the median of multiple oracles, requiring oracles to post collateral that will be forfeited if they disagree too much with the others, and using attested hardware (SGX) to make oracles more auditable.