Firstly theres this concept of space time. space time occurs in waves, mountains and valleys. Gravity bends space time. heres a brian cox video on space time.
So space time changes according to how close you are to Mass. Put another way, being close to someone changes spacetime – just a very tiny amount.
It takes a while to understand space time, it like Hawkings theories on quantum physics. We tend to work on the hum drum day to day stuff – time just is a constant – its 2 o clock in the afternoon every single day and the sun is in the sky somewhere. If you start to think that time travel happens all the time, you may become worried about the fragile “ego” world that you understand. Not understanding the world is frightening, worse perhaps when the world you have built has foundations and structures and all of that wobbles.
Heres another Brian cox video on this : https://www.youtube.com/watch?v=-O8lBIcHre0
So someone travels near the speed of light in a rocket for 5 years and then returns. According to their watch they spent 10 years in space.But he arrives on earth according to earth time, 29 years later. He is 10 years older, everyone else on earth has aged 29 years.
Why? because the time on earth is faster than the time in the rocket. Freaky. I still haven’t quite got my head around it.
So travelling in to the future is possible but probably not the way you thought if would happen. And theres that other neat little problem of actually trying to travel at the speed of light.
But hang on, you don’t need to. We must be time travelling all the time, we are all travelling at speed from time to time – on a plane in the car. Granted its not the speed of light but any speed should change the rate of time just perhaps not by very much.
Heres another one. https://www.youtube.com/watch?v=Mpw68rvF4pc that time thing again.
Course the main problem with travelling at the speed of light is mass. More precisely your mass. To travel at the speed of light we need to dispense with mass. What if we were travelling in spirit form only? spirit has zero mas. It therefore can travel at light speed…. Now whether you agree that spirit form exists or not the idea that your projected spirit can do this opens some very interesting ideas.