The Time Traveler's Life - Part One
By Allan EastmanGo back to Page 1
Time Travel and Science
Isaac Newton imagined a Universe that ticked along like a mechanistic clockwork. It had an infinity of Space and an eternity of Time. Gravity and motion were the key elements of his theories but it was essentially a static Universe, God-created and never changing. Time flowed forward in never ending regular motion, giving duration to all things.
Albert Einstein radically changed the human view of the Universe early in the 20th Century with his Special and General Theories of Relativity. The Universe is not static but constantly changing. Time and Space were intricately linked with each other and with matter and energy and light. Matter creates gravity and gravity affects everything, even light, which bends around strong gravitational attractions. Velocity matters too, in a way that is crucial to the idea of Time Travel.
Einsteinian mathematics demonstrates that the faster you travel, the slower Time passes – the so called time dilation effect. Similarly, huge gravitational pulls also slow down the passage of Time. The later discovery of Black Holes, the remnants of collapsed Stars, confirmed Einstein’s theories – both Space and Time are immensely warped in the vicinity of the massive gravitational forces surrounding a black hole.
Einstein’s time dilation effect is the one absolute certain way of being able to travel in Time. We could do it tomorrow - the only problem is that our technology isn’t currently sophisticated enough to accomplish it yet. The way it works is to get into a newly minted Starship and head off into Outer Space, accelerating constantly until your velocity begins to approach the speed of light – a tad less than 300,000 kilometers a second, or 186,000 miles a second - the apparent speed limit for motion in our Universe. When traveling at these kinds of relativistic speeds, Time will pass much more slowly for the people on board the vessel than for those people left back home. For example, a year may pass for the Astronauts on the Starship but when they return to Earth, they will find that 20 years have passed on their home planet.
This dilation effect elongates, the higher the speed and the longer the duration of the flight. It is demonstratably possible for travelers to go out to the visible edge of our Universe, out to where the light left near the Big Bang 13.7 Billion years ago and then return during the duration of a human lifetime. However, on Earth, Billions of years would have passed.
This, of course, is the great problem with relativistic speed Time Travel – that there is no way to reverse the process, to travel back in Time to a period close to when you left. Any space traveler that goes away for more than a few years will return to find his loved ones long in their graves and depending on the time dilation, his world so changed as to be unrecognizable. The past is really gone.
Joe Haldeman dealt with this issue in his classic Science Fiction novel, The Forever War. The book’s reluctant soldiers, who spend only a few years of their personal time out on the missions, are always unsure when they complete their time dilation trips whether they will be facing an enemy technology hundreds of years in advance of what their own is – that is, fighting enemies from the future. And worse, by the time they return from combat, 100’s or 1000’s of years have passed on Earth so they eventually become estranged from any of the original values that they were fighting for. In the end, Earth has become so alien to them that they don’t even want to be a part of it anymore.
You actually experience this kind of dilation Time Travel when you fly on a jet aircraft, although because of the relatively low speeds and short durations, the effect is measured in fractions of microseconds. But you are ultimately traveling in Time. Some Cosmonauts who have spent long periods in the Russian Space Stations have added a tiny portion of a second to their lives through time dilation.
Still not exactly the Time Machine we all want, right?
The kinds of physics laboratory experiments going on these days to attempt to find a way to travel in Time tend to involve the Einsteinian bending of light through the use of high powered lasers and magnetic fields in an attempt to create a sharp curvature in local Space-Time. Simply stated, they are trying to create, on a very small scale, the conditions near the event horizon of a Black Hole where Time is distorted on a gargantuan scale.
The problem with these experiments tend to be that there is absolutely no way that sufficient energy can be generated or concentrated enough to create the effect that they are looking for. One would really need to plug into a black hole to have access to that kind of power. Still, some scientists claim that their experiments are allowing them to move sub-atomic size particles miniscule amounts forward in Time. The particle apparently disappears and then re-emerges some infinitesimal duration of a microsecond later. Many of their colleagues seem extremely dubious of such claims.
Still, physics in our Universe does allow for Time Travel and newly developing theories may hold the key. It seems quite likely that wormholes generated by the gravity of black holes may create a passageway through Space and Time. It could be possible to pass through such a wormhole and emerge in a different part of the Universe at a different moment of Time with virtually no duration experienced on the journey. Technology requires major advances for us to give this a try though and one wonders who would be the volunteers to brave the first trial.
String Theory, the attempt to reconcile the contradictory properties of the Theory of Relativity for very large things and Quantum Mechanics for the very small, may provide a key. String Theory only works if one allows for the existence of a total of 10 or 11 dimensions – it still cannot decide whether Time is a dimension or not. But these other 6 or 7 dimensions which cannot be observed by us yet, may contain interfaces which would allow Time Travel.
To go further, the ideas of the Multiverse theorize many Universes coexisting alongside and outside our own observable Universe. Our Big Bang may be just one of many existing before, after and outside of our own and our “Laws” of physics might not necessarily be laws in every other Universe. Therefore, Time Travel may be a trivial affair in some of them. Indeed, once you start to think about it, it is easy to imagine Universes where Time runs backwards or sideways from the way that we experience it.
Science is rushing forward into new understandings that seem increasingly “magical” to the layman. Maybe that flux capacitor technology is lurking just inside one of these new ideas.