Temporal paradox
A temporal paradox, is a time paradox, or time travel paradox. It is a paradox, or logical contradiction, of time and time travel.
Temporal paradoxes fall into two broad groups. Consistency paradoxes (example: the grandfather paradox) and causal loops.[1]
A causal loop is a paradox of time travel. It occurs when a future event is the cause of a past event, which in turn is the cause of the future event. Both events then exist in spacetime, but their origin cannot be known.[1][2][3][4]
Temporal Paradox Media
A causal loop or "bootstrap paradox". A billiard ball delivers its past self a strike that slightly changes its trajectory in the exact way required for it to change its past trajectory. The change in trajectory appears to have caused itself.: Script error: The function "hyphen2dash" does not exist. 
A consistency paradox or "grandfather paradox". A billiard ball delivers its past self a strike that prevents it from entering the time machine that caused it to strike its past self, putting into question how its older self could ever emerge from the time machine and divert its course.
References
- ↑ 1.0 1.1 Francisco Lobo. Time, closed timelike curves and causality. Nato Sci.ser.ii 95 (2003). p. 289–296.
- ↑ Nicholas J.J. Smith. Time Travel (2013). Retrieved November 2, 2015.
- ↑ Leora Morgenstern. Foundations of a formal theory of time travel (2010). p. 6. Retrieved November 2, 2015.
- ↑ Klosterman, Chuck. Eating the Dinosaur (2009). New York: Scribner. p. 60. ISBN 9781439168486. Retrieved 2 February 2013.