I have to agree SS, that peace on earth will probably never truly happen. Sad to say but we must face realities.
Time travel makes for a great movie but I can't see it as a true viable possibility. Since I can't understand it it must not be possible, right? LOL. Once time is gone, it's gone. If it were possible someone would go back in time and screw everything up, you just know it would happen. It's the pessimist / realist in me.
New source of energy is a real possibility and that got my vote. I can see all houses run off the grid. Each will have a power box that will last 10 to 30 years. It will still cost and need serviced. Nothing is free, but it should lower the cost of energy overall (might be wishful thinking).
The new energy source could very well lead to jetson like mobiles / hover craft. That would be cool.