I want to borrow this guys space ship and go back to 1999!
Unfortunately time travel backward is not proven, but of course we are all time travellers forward, and this would be at different rates depending on your speed/acceleration.
You could in principle, place your savings in a safe long term investment 😕 (not exactly sure what this is though, probably not US bonds!) travel in a fast spaceship, come back again in one year when everything else has aged 100 years to find compound interest has worked wonders on your savings.
I worked out that 1 cent invested 400 to 500 years ago at typical returns from the stockmarket would make you the richest person in the world today (work it out if you don't believe this). I think all this prooves is that the system is flawed and stockmarkets/property prices are unsustainable in the long term due to war, political change and disease.
Still technical problems with the spaceship though, but it would be interesting to see how complex the annuity market would get if this became possible!
I understand the Apollo astranauts aged a few hunded microseconds more than earthlings in their journey to the moon and back but forgot to lodge an overtime claim 😉