Back to the Future 2

— Jennifer could conceivably encounter... her future self. The consequences of that could be disastrous.
— Doc, what do you mean?
— I foresee two possibilities. One, coming face to face with herself 30 years older... would put her into shock, and she'd simply pass out, or two, the encounter could create a time paradox, the results of which could cause a chain reaction that would unravel the very fabric of the space-time continuum and destroy the entire universe. Granted, that's a worst-case scenario. The destruction might, in fact, be very localized, limited to merely our own galaxy.
— Well, that's a relief.

- Jennifer could conceivably encounter... her future self. The consequences of that could be disastrous.
- Doc, what do you mean?
- I foresee two possibilities. One, coming face to face with herself 30 years older... would put her into shock, and she'd simply pass out, or two, the encounter could create a time paradox, the results of which could cause a chain reaction that would unravel the very fabric of the space-time continuum and destroy the entire universe. Granted, that's a worst-case scenario. The destruction might, in fact, be very localized, limited to merely our own galaxy.
- Well, that's a relief.
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