} Well, that couldn't happen, for the express reason that if it could, it
} would have already.
} Look at it this way:
} You go through a wormhole that will open up in pre-WWII Germany. Your
} mission, you think, is to kill Adolf, or at least persuade him to keep
} painting, thus assuring millions of lives saved. Problem: if you do
} this, WWII will never exist, thus making your mission unnecessary, and
} therefore obsolete, ad infinitum. Solution: paradox, destruction of
} the universe.
} Pity. It was so young, too.
} And that is the main problem with the "passive" approach to time
} travel. You can't just go surfing the chronostream undercover, do your
} duty, and then disappear back in the mists of time where you first
} emerged, or at least not without risking the entire cosmos in the
} process. No, if you're going to travel through time, you've got to do
} what you came there to do, and then announce to the world afterwards
} why you did it. Appear on talk shows, do the publicity circuit, and
} basically become world famous. Then, when time travel is invented all
} over again for the first time, people will know exactly what to do and
} where, and will have the documentation that it was successful. And
} causality is kept intact.
} Of course, that was supposedly the theory behind the man who is going
} to be known / history has recorded as Jack the Ripper...
} You owe the Oracle a better case study.