You Ain’t Seen Nothing Yet
What we observe may just be the tip of an iceberg.
| The startling assertion by world renowned physicist Stephen Hawking and his co-author Leonard Mlodinow in their recent bestseller, The Grand Design, that “Science can explain the universe without the need for a creator” generated worldwide headlines in September. Not as extensively reported, however, is the fact that for such a universe, or, even more remarkably, universes, to exist we require 11 dimensions instead of the familiar four dimensions of space and time.
Our perception of reality is a based on 3D images that our brain creates, and to aid that process it absorbs information from our surroundings, which is filtered through our sense organs. The models and laws we create are all based on that very same premise: that the external world operates in three dimensions. Is our brain capable of visualizing higher dimensional objects? Such queries demand a scientific search that connects physics with consciousness. Fish in a pond or bowl, if equipped to describe their outside world with mathematical equations, will definitely have a different set of laws than ours. Strangely, their equations will be compatible with the observations they make about the external world and they would expect their theory of the universe to be right. They might even argue that this must be true for every observer. Is that true for humans as well? Just because we look at our universe and create a model that explains how it works rather than why it works doesn’t mean we comprehend the complete picture. The fact is that our experience of the universe could be similar to that of the fish trapped in the bowl. We, fish and possibly every other observer operate within the constraints of their physical dimensions.
The physicists’ search for a theory of everything has landed them in the exotic worlds of 11 dimensions and many universes. What is equally shocking is that the so-called laws of nature, which we assume are the same everywhere in the universe, may not be so. The absolute laws of nature are giving way to laws that apply to particular universes. Additional dimensions and universes with their own set of laws and constants are no longer a nightmare for physicists, who are growing increasingly comfortable with realities that defy our common sense observations. The supreme truth and beauty of the cosmos revealed through mathematical equations by Einstein and Newton are fading. The absolute laws of nature are merely functionally effective, but imprecise laws of convenience. There may be no absolute truth, but only conclusions drawn from observations and premises. A few decades ago, physicists were enamored by string theory, in which the basic constituents were not tiny particles, but strings. The one dimension strings were believed to create cosmic vibrations in every possible way. The elegance of the string theory was admirable, but it faced profound theoretical and experimental challenges. The theory’s popularity has diminished and theoretical physicists are lost in the strange landscape of their own creation.
But, if other spatial dimensions exist, why don’t we experience them? One explanation is that these other dimensions are curled up and extremely tiny in our universe, making them invisible to human experience or our machines. “As of now, string theorists have no explanation of why there are three large dimensions as well as time, and the other dimensions are microscopic. Proposals about that have been all over the map,” according to Edward Witten, a pioneer in string theory and a professor at the Institute of Advanced Study, in Princeton, NJ. Edwin A. Abbott’s satirical novel Flatland: A Romance of Many Dimensions, used a fictional two dimensional square to offer experiences of a whole new three dimensional world with the help of a three dimensional sphere. The science writer Isaac Asimov suggested that Flatlands was “The best introduction one can find into the manner of perceiving dimensions.” Unfortunately, unless a four dimensional creature lifts us from this 3D spaceland and grants us a magic view, like the square in Flatland, we will never know about other dimensions. The hope of finding their existence, if ever, rests with the ongoing high energy experiments at the Large Hadron Collider in Geneva, Switzerland.
Some researchers are hopeful that at least some of the extra dimensions are big enough to measure, but that they might have shrunk as the universe expanded from its initial state. If so, the satellites deployed to map the picture of the early universe could reveal the faded signals of the extra dimensions. The late physicist John Wheeler, who coined the term black holes, said, “In order to more fully understand this reality, we must take into account other dimensions of a broader reality.” The additional dimensions may be key to explaining the weakness in our universe of gravity (see September issue), which is thought to leak into other dimensions, and such phenomena as dark matter and dark energy. The halo of dark matter that is assumed to be holding our universe together may partly exist in other dimensions than the ones we are used to. The Grand Design explains that M-theory proposes a humongous 10500 apparent laws, each of which can potentially create their own universe and ours happens to be just one of them. The model-dependent realism argues that from any given initial conditions and the ensuing chaos, a universe could emerge without the intervention of a divine being. The force of gravity can shape space, time, matter and life as dictated by the apparent laws of each universe. Just as a sheet of paper can be folded in many different ways, in fact, infinite ways, and each initial condition can give rise to a specific outcome, t
Our universe may be stuck in a three dimensional membrane making it impossible to detect other dimensions. Among all the known forces, theoretical physicists believe, gravity could be an inter-dimensional force making its presence in all possible universes. We may be the inhabitants of this three dimensional pocket, called our universe, which is part of a higher dimensional universe. But if the extra dimensions exist, they would leave behind a signature in our universe that could be detected. One such signature would be graviton, a particle that is supposed to be carrying the force of gravity. This yet to be seen particle may be trickling into other dimensions making gravity appear weaker here. “As far as extra dimensions are concerned, very tiny extra dimensions wouldn’t be perceived in everyday life, just as atoms aren’t: we see many atoms together but we don’t see atoms individually,” says Witten. In The Restaurant at the End of the Universe, Douglas Adams wrote: “There is a theory which states that if ever anybody discovers exactly what the universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.” Little wonder that Albert Einstein concluded, “Reality is merely an illusion, albeit a persistent one.” |
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