What is the best practice to interact from an Ethereum contract with the Bitcoin blockchain (e.g. look up a transaction)? Is it possible at all?
Is there a possibility to load data inside a contract from a non-contract source? Or is the only way how Ethereum knows something about the outside world to push those data to a contract and then request those data by other contracts? But then you need to trust that data feed provider and lose the trustless nature of another blockchain. But there is probably no way around that. Using oracles, voting pools or the like might mitigate the problem.