Timetravel is impossible

In the toy Big Bang model, light rays spread out as a function of time, similar to the expansion of spacetime in a diagram of the real Big Bang. Image credit: Smolyaninov and Hung.

Big Bang simulated in metamaterial shows time travel is impossible
(PhysOrg.com) -- By observing the way that light moves inside a metamaterial, researchers have reconstructed how spacetime has expanded since the Big Bang. The results provide a better understanding of why time moves in only one direction, and also suggest that time travel is impossible.

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