Man has changed everything he could in this world, except one. Dream to surpass time. And winning this race may take time equal to the age of universe itself, but determination in our heart would remain. Our very instinct will be the driving force which will inspire us to hope for victory.
Here are few of the hypothetical scenario which are given by Stephen Hawking which should allow us to travel through the time
1. Spaceship to Black hole
Black holes are very interesting formation of space-time (refer The Black Hole: Facts and Basics ). Now in order to move ahead of our present, all we need to do is wait for NASA to create a spacecraft like Millennium Falcon, sit in it and travel all our way to a black hole. When we will cross the event horizon, we will probably see a dark black ball sucking everything into it. If we revolve around the black celestial sphere, one or two times and return back to our home, the earth, we will notice that things have changed drastically. We will probably see a robot welcoming us to the future, cars flying, buildings with crazy design, people with weird sense of dressing etc. Although it is not possible to return back by escaping gravitational pull of the the black hole, but who knows. Maybe someday with help of Tachyons like materials we will able to achieve unbelievable.
2. Journey through Wormholes
Wormholes are another weird space-time tunnels which are found in microscopic domain. Inside atoms, wormholes are frequently used by electrons to travel throughout its orbital and form an electron cloud.
At macroscopic scale, these wormholes becomes unstable. This is because any energy entering the wormholes travels through it, gets amplified, crosses the universe back into the wormhole. With every cycle energy amplifies again and again and again until it mikes a wormhole unstable. It is like a sound traveling through mic, emitting through speaker and entering the mic again. This causes a loud screech which can destroy the speaker itself.
We cannot travel faster than light, but we can take a shortcut by passing through a giant wormhole to the other end and capture the beam of light from the past. If we develop a technology which could enable us to expand a tiny wormhole, we could solve the problem of both time travel and teleportation.
3. Travel in Light Speed Train
Now this is the most convenient, practical and fastest way to time travel. We will have to create a train which can travel around the earth at speed of light. Now the passengers sitting in this train will travel at speed of light though space and hence their velocity through time would become zero (refer Why People Age Faster In The Hills: Einstein Answers ). While on the outside world, time would be passing through its usual speed. When our journey end after hundred years with respect to earth, the passengers would feel that not more than a minuet had passed since this journey had begun. So in one minuet passengers have enter the future world. They will similarly see flying cars, robots, etc.
All these methods are hypothetical. This race will be the most challenging race we will ever encounter. But impossible is the word in the dictionary of fools.