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Time At A Bus Stop.
This is a tad of a digression from the original topic of the supposed canonical, chronological, topical order of my blog posts (anyone expecting information on WIMPs et al. I apologise, that post will be on the way shortly), but I thought I would spare this little diversion, to turn my attention to time travel.
Time travel is one of the hottest of potatoes and one of the most fictionalised, dramatised and most romantic of aspects to the masses in physics terms. From HG Wells to Marty McFly, it is pretty much the superstar of cosmological theories and thought experiments. However, all of the stories surrounding this topic fail to answer one question, a question still hotly debated among scientists today: is time travel possible?
Time has existed from the expansion of the Big Bang, a rapid expulsion of matter outwards from a point of a singularity. Recent models of cosmology posit that the universe's expansion to it's present size is aided by Dark Energy. We are fairly knowledgeable of where we come from and we have a good idea the route existence will take in the future. But the onus and the question on many people's lips, including physics leviathans like Einstein, is time travel possible, or plausible?
The first to tackle this issue with a tangible method was, oddly enough Einstein, with the "Einstein/Rosen Bridge," more affectionately known as "A Wormhole." What is a wormhole? Well, maybe the solution for a portal like a wormhole will become clearer after some of the difficulties of the universe are laid out.
Firstly, there seems to be a cosmic speed limit, the speed of light. Light travels at approximately 671,000,000 miles per hour. A vast distance (considering our farthest probes, the Voyager probes, are currently 14 light hours away from earth and have been traveling through space for 37 years!) There is the possibility of moving faster, the universe has definitely moved faster than light and a recent disparity with particles known as neutrinos were shown that they traveled marginally faster than light (revealed to be erroneous computer data). There are also the (as of yet) theoretical tachyons.
The speed limit has implications for everyone. Mere mortals, nebulous gas and starlight. As far as we know, nothing can move faster, any object with mass will become infinite at C (light speed). Possess a smidgen of mass and it grows endless, Space/Time is image conscious, or so it would seem!
An Einstein/Rosen Bridge seeks a way around this pickle, literally to "bend" the rules of the cosmos, by utilising the wormhole. Wormholes seek to circumvent the rigid rules of the Space/Time continuum. The most common proposal for this method is a "folding" of Space/Time, therefore bringing two points, many light years distant (Light Year = Approx. 5.8 trillion miles) much closer to one another. The wormhole itself is a funnel through Space/Time where the effects of time on travel are avoided. Travel at the speed of light and you move faster than the matter around you. You as a vessel/voyager would have traveled much faster, aging much less than those you have left behind. A wormhole dodges this dilemma, the tunnel overrides the limitations by making only the beginning of the wormhole, the end and the vessel within, sole constituents of that reality, so time and space reside without. The notion is that the journey to distant points in the universe would be drastically shortened.
How to fashion a wormhole though? How does a species of sentient beings burrow through the soil that is the fabric of the universe? Some theorise postulate harnessing a star's energy may yield the results, forcing the strength of our sun's awesome nuclear fusion. There are others that believe black holes are already the blueprint for an Einstein/Rosen Bridge. The singularity within a black hole may mimic the point in time for a vessel crossing the shortened space of a wormhole.
However, the fabric of the universe itself may yield results to clues about time travel. For example, James Clerk-Maxwell revealed how light can behave as both a particle and a wave. Light is the messenger of the heavens, it is pushed outwards by what we believe to be Dark Energy, racing out from the ultra dense singularity at the point of creation. Every point of these wavelengths of light radiated out from one place, traceable via the Cosmic Microwave Background. From it's momentum, we are also able to predict where the universe is going. What if these waves can be reversed or sped through to points in the past or future? Wild speculation, I know. But we are stumbling across more wonders of the universe with each day.
© Brad James, 2014.