but the possibility of travelling to the future is real.

DR. RONALD MALLETT: [Laughs] You got it.

DR. RONALD MALLETT: I had to keep my passion for time travel a secret for decades because

I wanted to build up my credentials as a legitimate physicist and the thing is is that any legitimate

physicist who was talking about it was risking professional suicide to talk about it. It's

been a rocky road because you're not getting the support that you need because you're not

telling people who might help you what it is you're trying to achieve, even those closest

to you. And I can remember feeling very depressed because I felt like I was getting nowhere

in trying to understand how to build a time machine. And there would be times in which

I would just sit in a dark room listening to Simon & Garfunkel pondering whether all

of my life had been a waste to do this. I started actually getting heart palpitations.

I was put on medical leave for about 6 months. This condition..um..which I was being treated

for was the thing that led to my breakthrough because for the very first time in my career

I was totally isolated. That is to say I didn't have anything to do except think about all

of the information I had been processing for decades about the various possibilities.

DR. RONALD MALLETT: Time travel is now entering into the domain of the legitimate. That is

to say that the present generation of physicists who grew up with Star Trek are now the ones

who are part of the legitimate community. So it's much more open. Although the way in

which it's stated in scientific publications, which is code words like "close time-like

loops", which is the same thing as talking about time travel to the past. A number of

physicists are working on various ideas. One of the most well known is the notion of the

wormhole. A wormhole is just simply...a very simplified way of thinking about it is that

suppose you have a rubber sheet..a flat rubber sheet. And suppose you cut a hole in one side

of the sheet and you cut a hole in the other side of the sheet and you connect those two

holes with a tube, that's a wormhole. This allows shortcuts through space and time and

it turns out that by manipulating a mouth of a wormhole in the appropriate way, its

possible for a space traveller to travel through a wormhole and come back and see themselves

travelling back into the wormhole in the past. So a wormhole is a possibility. The other

possibility are what are known as cosmic strings. These cosmic strings are long lines of matter

that are..were created. They're sort of like fault lines in the universe that were created

after the universe was created. And these..if these fault lines are passing eachother, these

these cosmic strings are passing eachother, they can create a loop in time and along that

loop in time and along that loop in time you can go back into the past. So this is another

mechanism. And then there's my work, which I found a different way. It turns out that

in Einstein's theory, not only can matter create gravity, but light can create gravity

as well. If gravity can affect time and light can create gravity, then light can affect

time. And so my idea was to use light to manipulate time. My time machine would essentially look

like a tunnel of light. It would look like a circulating cylinder of light. Think of

the coffee in this cup as being a portion of space and think of the spoon as being like

a circulating light beam. Imagine, now, that if I take the spoon and stir the coffee, you

can see what' happening to the coffee. That's what the circulating light beam is doing to

empty space. The circulating light beam is causing empty space to get swirled around

and creating a vortex. But if you stir it strongly enough, it can actually begin to

twist time into a loop because in Einstein's theory, space and time are linked to each

other. Whatever you do to space also eventually happens to time. So in addition to twisting

space, you will eventually twist time into a loop and along that loop in time you can

go back into the past and that's the core of my idea.

DR. RONALD MALLETT: What I didn't realize when I began was the fact that there was gonna

be a limitation. For instance if I turned the device on today, a loop in time will begin

to form. And if I leave it on, for example, let's say 10 years, someone could travel from

10 years back 7 years, 5 years, all the way back to the beginning where the machine was

turned on. But they can't go back earlier than that because the machine didn't exist

earlier than that. That means that time travel to the past is possible, but only from the

future after the device is turned on. You're not gonna be able to travel earlier than that,

which answers the question why we haven't see time travel tours because that means that

the first human scale time machine hasn't been built. But that meant that I was going

to be blocked from my possibility of visiting my father, which was very bittersweet for

me. However, I have to say that one of the things is is that because I've reached the

goal theoretically, I feel that that's something that my father would have been very very pleased

with, that I have achieved that. And it allows me, I have to say, to be passionate but its

not as all-consuming because I now realize that in addition to wanting to control time,

it's important to want to live in time. And ultimately, for all of us, even though time

travel will allow us to have an unprecedented control of our destiny, we all only have the

present moment in our lives and it's important to live that moment as fully as possible.

That's what I have learned.