We are already travelling through time.

yes but god give us some lines for determining what's reasonable and what's not  and i mean by this lines ( sciences ) 

This will NEVER occur, these are rules of God. God only can know and determine what may happen in the future, science may enable us to predict the possibly events.

But Ezzat, by science we can do anything, Don't we ?

so why you think that wouldn't happen ?

Respect -Give2Get-

Travel to the future is possible, but not to the past. So if you go to the future you can never return to your original time. Travel to the past imply many paradoxes, for example, if I build a time-machine that allows me travel to the past, I could give it to myself before I had to build it.