Science Forums 2

[futuretalk]

University of Connecticut’s Dr. Ronald Mallett thinks he has found a practical way to build a time machine using light. He hopes to verify the concept within 10 years, and expects a machine built this century. “No known laws of physics forbids time travel”, Mallett says, “and in theory, shunting matter back and forth through time shouldn’t be that difficult”.
But what about wormholes, those clever little tunnels in spacetime that supposedly enables travel from one moment to another? Though wormholes seem a perfectly respectable way to travel through time on paper, developing them would require capturing energy from all 400 billion stars in our galaxy, a feat that for now remains far out of reach to say the least.
Mallett however, who is a theoretical physics professor believes he has found a route to the past that uses something much more down to earth: light. His team discovered that light beams can create a vortex that force the past, present and future to circle one another until the future precedes the past.
Their research suggests that tiny bits of matter can be moved from the present to the past. And if it works for matter, in theory, it can transport us.
As you enter Mallet’s futuristic time machine, your mind senses that you are moving forward, but because of the spacetime vortex, you are actually going backwards through time. You can exit the machine at a preset time and place in your past.
But journeying to the past opens controversies. Say for example, we travel back in time and prevent our parents from getting together: this would prevent us from being born; we would not exist, therefore our journey in time couldn’t happen. This creates a paradox – a past different from one that already exists.
Luckily, mischievous time travelers cannot alter our present. People do not suddenly disappear because a rerun of events has prevented their birth. Therefore, something must be preventing time travelers from making changes that affect today’s world, and physicists Daniel Greenberger and Karl Svozil believe they have the answer.
Before we observe an event, there are many possible outcomes, but once we become aware of the end result, the possibilities shrink to one. If you know your parents were together, there is no possibility of them not getting together. If you tried separating them for instance, you might arrive after they left the room, could not find them, or changed your mind. Something will always prevent the past from being changed.
However, another theory rapidly gaining popularity includes the multiverse. If you travel back in time and change history, you immediately thrust yourself into a parallel universe. In our universe, your parents were together and you are here; in the universe you jumped into, they never met, and you appear as a stranger from another universe. Be careful though, once transferred, you can never return home.
None of these paradoxes worries Mallet. He thinks the multiverse theory is probably correct, and quickly adds that just because we don’t fully understand our universe, doesn’t mean that time travel can’t happen.
Will our “magical future” include time travel? Only time will tell!