millions or even billions of years from now. Long enough to become an entirely different kind of being, living in an entirely different kind of spacetime. Them trying to communicate with us would be like us trying to communicate with an amoeba. We wouldn't be able to communicate with them directly, we'd just have to coax them into doing what we need them to do.

Yes, it's a Macguffin, but nothing out of the ordinary for adventure movies.