Time Travel via Parallel Universes: Part One

Parallel universes, or alternative universes or mirror universes have had a long run of popularity in science fiction and science fantasy, in both print and visual formats. One need only look at an “Alice in Wonderland” or look no further than the “Star Trek” universe (our Universe in less than obvious disguise) to view the near endless plot variations that such parallel / alternative / mirror universes provide our heroes and heroines. While there are some serious reasons to suspect that parallel universes do exist, there’s another, albeit more theoretical proof of the parallel universe concept. Time travel is the name of the game!

Why go back in time at all? Just to observe? That’s okay, as long as you look and don’t touch. Just to get rich? Probably! Just to do good deeds? I’d have to advise against that. Travelling to the past from the future, armed with the knowledge of what that future holds, brings a ‘wealth’ of opportunities – accent on the wealth. I mean go back in time and there’s this new company called IBM or Microsoft just starting to sell shares. You’d make a killing! You know in advance about the Global Financial Crisis. Put that to your advantage! Knowledge is power. Maybe all our billionaires are time travellers from the future who came back to make a killing! Sorry for taking such a cynical view. Actually the danger is the ‘butterfly effect’. Go back in time, be a goodie-goodie two shoes and correct something – kill Hitler in 1935 say – and the ripple effect could have so changed the future from which you came from that you might never have existed. Say that soldier in WWII, killed by the Nazis, lived instead because you assassinated Hitler in 1935 and he married your Mum instead of your Dad. You were then never born. Or say you assassinated Hitler in 1935, and someone else took over the leadership, but that someone started up Germany’s nuclear program almost immediately. Thus, Germany had the A-bomb when she started WWII – Germany won! Of course maybe somebody else goes back in time and assassinates you just before you bump off Hitler! Lesson: You do not muck around by changing the past since you can’t predict the rippling effects on down the line. Ray Bradbury’s excellent short story (also filmed) that illustrates this point nicely is “The Sound of Thunder”.

Be that as it may, I can immediately think of four actual, possible or theoretical ways of doing the time warp – again!

The first is your tried and true traditional time travel into the future, and one which you have no control over – we all travel into the future at the speed of one second per second.

Secondly, there’s a possible albeit highly theoretical equivalent for an antimatter you. You’d have a tried and true traditional time travel into the past, again one which you have no control over, and again (presumably) at a rate of one second per second. That’s because of the idea that antimatter is just normal matter, but normal matter going backwards in time at the rate of one second per second. I don’t rate that too highly on the reality scale. 

Thirdly, when you view any object, you’re time travelling back into the past. That’s because it takes a finite amount of time for light to reach you from whatever it is you’re looking at. What you actually see is how it looked that finite amount of time ago. Since you always view what happened in the past, I guess that’s a form of time travel! By the way, even if you directly touch or taste something, it still takes a finite time to travel on up the nerves to the brain and a finite time to register and be processed.

Fourthly, there’s the concept that if you travel and accelerate outwards at a significant percentage of the speed of light, stop, reverse, accelerate and come home again, when you land, you will have aged less than those stay-at-homes, or translated, you’ve travelled into the future a lot quicker than otherwise would have been the case. You and your stay-at-home twin are now both at the same point in time again; it’s just that you have biologically aged far less. That’s the ‘twin paradox’ of relativity physics, but it’s no paradox – it actually happens.

Interestingly, at the micro, hence macro levels, the laws of physics do not forbid other ways and means of time travel, for example using rotating Black Holes, wormholes, etc. While these are theoretically possible, in practice it would be difficult in the extreme, very energy intensive, and certainly way, way beyond our current, or even projected, level of technology, and may indeed remain forever out of our practical experiences and thus remain a parlour game for physics professors. But maybe, just maybe…

However, for starters, there’s a catch – there’s always a catch! Travelling backwards in time is restricted. You can’t travel back in time beyond the point where the time travel device was first constructed. If we should construct such a device in say the year 2050, nobody will be able to visit 2949 or any earlier date. Thus, since no such terrestrial device yet exists, we’re not overrun by tourists from our future. Our descendents can’t reach us. We cannot have time travelling visitors from the future who can tell us our future because they are not from our future, but from the future of an elsewhere – you guessed it, from the future of a parallel universe where a time travelling devise exists.

The reason, as I understand it, that you can’t time travel in your time travelling device before the device itself existed, is that your device isn’t a machine or a device you sit in – it’s a medium. It’s likely to a natural object, even if manipulated – rotating Black Holes or wormholes. A tunnel allows you to go from one side of the mountain to another, but in doing so you don’t take the tunnel with you. A ship travels through the water – it doesn’t take the water along with it. A tennis ball gets hit by the tennis racket; it doesn’t take the racket along with it. Instead, it relies on finding another racket in its new ‘universe’ or ‘time frame’ or court, able to return it home! You probably get the drift. That’s why you can’t go back in time further than the medium itself you used. If your mountain tunnel was built in 2009, you can’t go through and exit it in 2008! But you could go through and exit it in 2010, so you’re not of necessity stuck in the past if you get the analogy. The tunnel allows travel both ways, but just not before it was constructed. Anyway, forget your time travel movies with machines – no machines allowed. Probably the best movie to illustrate the point that the device is a medium and not a machine is “The Final Countdown”.

That of course says nothing about extraterrestrial intelligence(s) time travellers who may have had a working time travel devices eons ago, so we certainly can’t rule out, or preclude such a possibility – there’s those pesky UFOs again!

To be continued…