A physicist dreams of time machines

Since 2001, when he delivered a paper on using lasers to manipulate space and time, Ronald Mallett has been one of the leading figures on the theory of time travel.

Although time travel has been a lifelong goal for Mallett, a 61-year-old theoretical physicist at the University of Connecticut in Storrs, it took him a while to tell his colleagues. He eventually told a fellow physicist in 1998.

“You have to remember that I was a tenured physics professor by this time, so I didn’t worry about it getting back to my department,” he says.

His friend encouraged him to develop his ideas, and a few years later, Mallett made headlines around the world.

Many people are skeptical that a time machine could work, noting that affecting time and space would take more power than is feasible. But Mallett’s fellow physicists generally agree that his ideas are theoretically sound and consistent with Albert Einstein’s theories.

In October, Mallett published “Time Traveler: A Scientist’s Personal Mission to Make Time Travel a Reality,” co-written with Bruce Henderson (Thunder’s Mouth Press, $24.95).

When Mallett was 10, his father died of a massive heart attack at age 33.

“I went from being a rather happy kid to a depressed kid. One of the gifts my father left me was a love of reading, and I came across the H.G. Wells classic ‘The Time Machine.’ That became the turning point in my life. I thought, ‘Wow, what if I could build a time machine? I could see him again and tell him what would happen.’ That became the Holy Grail for my life.”

In an interview, Mallett patiently explained time travel’s intricacies. It’s complicated; some of his answers are paraphrased.

What does a time machine look like?

Mallett says it would fit comfortably within a regular room. The device would use light to create an enclosed area by bouncing the beam off a series of mirrors. At its center would be space-time. Comparing this space-time to a cup of coffee, Mallett says he would use laser beams to stir up a swirling effect -- conditions that would allow for jumping forward and backward in time. He’s still seeking funding for the first phase of the machine’s development, which he estimates would cost $250,000.

How soon can we go back and prevent Lincoln’s assassination?

Never, according to Mallett’s theory. Because the machine creates its own loop for time travel, you can’t go back to a time before the machine was created. That’s why we haven’t been visited by folks from the future. It’s also why he has realized that he will never save his father.

Besides, Mallett isn’t even thinking about using people as subjects at this point. His first goal is to send a subatomic particle back a few nanoseconds.

A time-traveling subatomic particle is impressive, but when might people do the same?

Sometime this century; beyond that, Mallett won’t speculate. Who could have known how fast air travel would progress after the Wright brothers flew at Kitty Hawk in 1903?

All those problems that Marty McFly ran into in “Back to the Future” -- meeting his parents, meeting himself, changing history -- are any of those real concerns?

“Very definitely, because you do have that classic notion of the ‘grandparent paradox.’ If you go back to the past and prevent them from getting married, they don’t have your parents, and then they don’t have you. So what does that mean for you? Do you just disappear? It is something that has to be considered.”

Luckily, quantum theory is there to posit alternate universes for alternate scenarios.

“Suppose at lunch today you’re trying to decide between a fish sandwich and a cheeseburger. As soon as you make a decision to have a cheeseburger, there’s another you who has chosen to have a fish sandwich. For every decision that you make, there’s an alternative universe.”

So if you do go back and change the past, “that past is not the time that you came from. It’s the past in the new universe.”