by Honor Harger (with small edits and transclusions by nik gaffney)

basically, it appears that thanks to the popularisation of the eleventh dimension, a rock climbing physicist's fascination with parallel universes, and some crazy talk by three physicists stuck in a train on their way to london, we now understand everything…

Yep, its sorted now. We apparently understand more or less everything about where the universe began, what started it, and what's in it. It turns out we live in a lumpy multiversal sea where bubble-like universes are thrown into each other like tidal waves.

Here is the deal …..

In the effort to establish a unified theory of everything, a theory of matter was developed in the 1980s and 90s called String Theory.

For years it had been an article of faith that all the matter in the Universe was made of tiny, invisible particles. In the 1980s the particle physicists discovered they'd been studying the wrong thing. The particles were really tiny, invisible strings. The theory was called String Theory and it maintained that matter emanated from these tiny strings like music.

As physicist, Burt Ovrut comments: “you can think of it as a violin string or a guitar string. If you pluck it in a certain way you get a certain frequency, but if you pluck it a different way you can get more frequencies on this string and in fact you have different notes. Nature is made of all the little notes, the musical notes, that are played on these super-strings.”

Another physicist, Michio Kaku reiterates, “All of a sudden we realised the Universe is a symphony and the laws of physics are harmonies of a super-string”

String Theory proved provocative. It was widely considered to be the closest theory to explaining everything which existed in the Universe. It seemed to neatly summarise the material aspects of the universe.

String Theory utilised additional dimensions in its framework. The extra dimensions were spaces in the Universe which we could not perceive. String Theory was characterised by considering the universe as a ten dimensional, but other theories used different numbers of dimensions. For instance, super gravity, argued by Michael Duff of the University of Michigan, was a comparatively obscure theory which had long existed in the shadow of String Theory, as a single unifying universal theory. Super gravitists posited that the Universe was composed of 11 dimensions. The Eleventh Dimension had always been ridiculed by String Theorists.

If String Theory was to become Einstein's missing Theory of Everything it would have to pass one test. It would have to explain the birth of the Universe. The origins of the Universe had always been the subject of the cosmologists who believed things had started with a giant explosion - the Big Bang. While initially String Theory and the Big Bang seemed to work perfectly in tandem as dual explanations for the Universe (one explained its origins, the other everything which existed in the Universe), problems soon started to emerge.

In the early 1990s a major problem with String Theory developed. As more people worked in it, competing theories began to be developed, variants on the original premises of the theory. In the end, five separate theories existed, each a subtle variant on the original String Theory. For a theory proposing to address the universe's questions, this was a major problem. String Theory's credibility rested on its claim to be a single answer to the universe's mysteries.

At the same moment, String Theory began to break down, cosmologists began to have major problems with the Big Bang as a theory of explaining the origin of the universe. As Alan Guth, a cosmologist explains: “In spite of the fact that we call it the Big Bang Theory it really says absolutely nothing about the Big Bang. It doesn't tell us what banged, why it banged, what caused it to bang. It doesn't even describe, doesn't really allow us to predict what the conditions are immediately after this bang.”

In the early 1990s, with String Theory in tatters, a group of physicists tried one last variant in their calculations. In a final desperate move the string theorists tried adding the very thing they had spent a decade rubbishing: the eleventh dimension. Something almost magical happened. When the calculations were re-done, with the addition of the new dimension, all five variants on String Theory turned out to be the same theory. The five String Theories turned out to be simply different manifestations of a more fundamental theory. The additional dimension, had not only solved String Theory's problems, but also had rehabilitated the work of the super gravitists who had long been operating in the Eleventh Dimension.

It looked as if a single unifying theory explaining the universe was, after all, plausible.

The new dimension - the Eleventh - was a strange place. It was calculated to be infinitely long, yet extremely narrow in width - an estimated trillionth of a millimetre wide (and thus imperceptible). The laws of physics as we know them would likely not operate in this dimension.

When scientist began to experiment using the Eleventh Dimension, something very odd began to happen. When physicists began to recreate their experiments using the additional dimension, they began to discover that the 'strings' of previous theoretical assumptions, were turning out to be distinctly 'unstringy'. The stuff which all matter was composed, in this new theory seemed much more lumpy, more elastic than a string. Now, with the addition of the eleventh dimension, the tiny invisible strings were changing. They stretched and they combined. The astonishing conclusion was that all the matter in the Universe was connected to one vast structure: a membrane. In effect, our entire Universe is a membrane. The quest to explain everything in the Universe could begin again and at its heart would be this new theory. Membrane Theory, or M-Theory for short.

( While all of this took place a rock-climbing physicist from Harvard University - Lisa Randall - had been greatly troubled by one of our physical forces: gravity. Why was it that gravitational force was so comparatively weak, when compared with other physical forces? Though intuitively gravity seems rather strong - it fixes us to the planet, for instance - it is in fact surprisingly weak. Despite the force of the sum of the Earth's gravitation pull on us, we are still able to move, for instance. Gravity's force can be overcome extremely simply, by using a weak magnet. A metallic object such as a pin can be lifted out of gravity's pull very simply using such a magnet. Why is this? Could it be that its force is being dissipated in some way? Could gravity be somehow 'leaking' into, for instance, the Eleventh Dimension? When Lisa Randall carried out experiments to check the validity of this hypothesis, her calculations wouldn't compute. Then, she started to consider a bizarre proposition. Instead of gravity leaking from our universe into one of our more unusual dimensions, could gravity be instead originate from a different membrane, elsewhere, and be leaking into our universe? In effect, could gravity come from a parallel universe? When Lisa Randall redid her calculations using an alternative membrane as a point of origin for gravity, she resolved her equations. The weakness of gravity could at last be explained, but only by introducing the idea of a parallel universe

The concept of a parallel universe seemed to be hypothetically plausible, under M-Theory. Now suddenly physicists all over the world piled into the eleventh dimension trying to solve age-old problems and every time it seemed the perfect explanation was another parallel universe. Everywhere they looked it seemed they began to find more and more of them. From every corner of the eleventh dimension parallel universes came crawling out of the woodwork. Some took the form of three-dimensional membranes, like our own Universe. Others were merely sheets of energy. Then there were cylindrical and even looped membranes. Within no time at all the eleventh dimension seemed to be jam-packed full of membranes. Physicist Burt Ovrut also proposed that occasionally membranes would collide. Universes in the Eleventh dimension would behave in much the same way as massive turbulent waves, occasionally banging into each other, creating vast disturbances.

M Theory was getting stranger and stranger, but could it really be a theory which explained everything in our Universe? To have any chance of that it would have to do something no other rival theory had ever been able to do. It would have to make sense of the baffling singularity at the beginning of the Big Bang.

In 2002, Neil Turok, Paul Steinhardt and Burt Ovrut had a crazy conversation in a train on the way to London. They wondered if the Big Bang might be the aftermath of some encounter between two parallel worlds. Membranes which behaved as waves do, membranes which ripple, would, in a collision create clumps of energy, some of which could form into matter.

The singularity had disappeared and it had taken them just under an hour. If it computed it later experiments, M Theory may really be able to explain everything in the Universe.

Later experiments and calculations seem to have borne out the train chat. It seems indeed that our universe could be just one bubble floating in an ocean of other bubbles.

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Category Physics