Proof that time travel will never be a thing. Otherwise, a time traveler could come back and short the currency and make a fortune. Imagine if someone shorted Zimbabwe dollars and parlayed that into shorting the Bolivar...
Well...it is...sort of.
As one travels faster towards the speed of light, time 'dilates' and slows down for the traveler. This has been proven and done.
However, traveling to the past would be impossible.