And it’s one of Einstein’s lesser known ideas, although a simple cup of coffee can show the principle. “Imagine that space is like the coffee inside this cup. As I stir the coffee it swirls around due to the motion of the spoon. And suppose that I drop an object like this coffee bean inside the cup. What’s happening is that it’s not moving through the coffee, but rather it’s the coffee that’s moving the bean around.” This rotating space applies the boost that’s needed to allow an object to break the light speed barrier without violating the laws of physics. Within that rotating of space you can travel speeds up to the speed of light, but for someone that’s standing outside it would appear as though you’re travelling faster than the speed of light. And for them you will disappear from sight as you’re travelling back into the past.
Of course there is a problem with this kind of time machine, for black holes are not exactly readily available. However, this is where Ron had a stroke of inspiration. He realized that hidden in Einstein’s theory all along there was something that could be even better at twisting space, light itself. “It turns out that light is much more effective at twisting space than time, so my idea is to use a circulating light beam to twist space and close time into a loop. The key technical challenge is to get enough laser power to cause this twisting of space and time, that’s going to be the key challenge. And we’re looking at several different possibilities to overcome that challenge.”
Modern laser technology is extremely advanced. Lasers exist which can create conditions that are as hot as the center of the sun. An array of such devices could be made to fire simultaneously producing not just a tiny ring but a cylinder of light with enough power to twist space. An elementary particle fired on a cork screw shaped path down into this tunnel would wind its way into the past. Seen from outside this experiment would have some pretty bizarre consequences. “I expect that particles might just simply appear out of nowhere even though I didn’t put anything into the machine and those would be particles that would be from experiments that I perform next week or a year from now in which I’m sending particles back to my time so that what I’m seeing are particles that I put into the time machine tomorrow or next year.”
But there is one inescapable drawback to this machine, no matter how powerful Ron could never use it to see or even communicate with his dead father. “This is a real time machine and that means if you turn it on today and you leave it on it will only act during the time that you have it on. So if I turned it on today and I leave it on for 100 years then I can travel from 100 years from now up to today but I cannot travel before the machine was turned on. For me the solace that I get from that is the fact that I will have achieved this goal and it was inspired by my father and I think that if, you know, he would have lived he would have been very proud of what I had been able to accomplish. So that gives me solace; that I will have accomplished an understanding of time and created a time machine. And I will be able to live with that.”
So while we might be able to think that a time machine would open up the past that’s not strictly true. It’s only in the future that time travel to the past is possible, and then only as far back as the moment the first time machine was activated. But of course this begs the question, what happens when you first switch on the machine? “It’s conceivable that when I turn the machine on I start getting messages from the future, from people who are trying to communicate with me. That would be a possibility, I mean it’s weird but it definitely would be a possibility.”
The project to build the machine has only just begun, but it is an endeavour with consequences that are hard to overestimate. If all goes to plan it could be stable enough to keep twisting time for a century or more, becoming in effect a phone line to the future. Anyone with access to the machine could send any kind of information back to that first…