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A history-altering time ripple approaches from the future at a rate of -263,000.note That's half a year per minute, backwards in time. The date and time are currently 8:36 pm, June 28, 1960, and the ripple is still 20 years into the future. At what time will the wave hit?
Answer: 9:16 pm, same day.note -20 years/(-.5 year/min) = 40 min.
Why weren't we affected by the ripple on June 28, 1950, when it hit that date?
Answer 1: Because the ripple didn't/won't hit 1950 until 1960. In 1950, the ripple was 2.63 million years into the future, or hadn't been generated yet.
Answer 2: Who says we weren't affected in 1950? Once the ripple hit us in 1960, the new history became the true history. Therefore, we were affected in 1950.
Zig Zagged: Combining You Can't Fight Fate with this results in Alice going back and changing the past, but that change already happened. However, this is just one shown timeline, and the action happens in more than one, and effects can be seen in other timelines.
Averted: Alice doesn't change the past at all.
Enforced: A movie director thinks it would look cool and changes the script to make that happen.
Lampshaded: "Okay, it should be about 20 minutes before I cease to exist."
Invoked: A Mad Scientist builds a machine that uses this effect specifically.
Exploited: The Cessation of Existence effect mentioned above is used to commit crimes and cause a large amount of problems and leave no suspects.