Henry's answer makes a good point: a miricle of prophesy could not only avoid the CGI issue with documenting events, but continue to convince future audiences.

Someone active today could easily leave terabytes of information as computer files. This could be replicated and seen to exist by many, and not be switchable like a magician's envelope because everyone has an independent copy.

It could include annual predictions that are unlocked by keys derived from data received from distant quasars, or cracked once the technology has progressed or time spent brute-forcing.

The annual file opened might refer to current events and use file formats of the day. And, include a renewal of any message to impart.

This would convince people that time travel or reverse causalty is possible, anyway.

How about a durable supernatural artifact that would still be inspected and studied in that far future? It would convince people that known physics is not all there is. It could be designed to cut to the heart of the most fundamental principles, so it can't be explained as just another as yet unknown thing. It could have continuing subtitles that freshly astound generations with greater depths of understanding of normal physics.

But why is ordinary evidence needed? The show Stargate SG1 had a sequel movie called Ark of Truth that would simply convince anyone exposed to it.

Henry's answer makes a good point: a miracle of prophesy could not only avoid the CGI issue with documenting events, but continue to convince future audiences.

Someone active today could easily leave terabytes of information as computer files. This could be replicated and seen to exist by many, and not be switchable like a magician's envelope because everyone has an independent copy.

It could include annual predictions that are unlocked by keys derived from data received from distant quasars, or cracked once the technology has progressed or time spent brute-forcing.

The annual file opened might refer to current events and use file formats of the day, and include a renewal of any message to impart.

This would convince people that time travel or reverse causalty is possible, anyway.

How about a durable supernatural artifact that would still be inspected and studied in that far future? It would convince people that known physics is not all there is. It could be designed to cut to the heart of the most fundamental principles, so it can't be explained as just another as-yet-unknown thing. It could have continuing subtitles that freshly astound generations with greater depths of understanding of normal physics.

But why is ordinary evidence needed? The show Stargate SG1 had a sequel movie called Ark of Truth that would simply convince anyone exposed to it.