The World of Braneworlds: Part One

For millennia, New Age devotees have related observations of nebulous exotic entities from apparently alternative realities like Parallel Universes that have made a crossover into our reality. Rational people suggest that’s just so much bovine fertilizer. Or is it? Perhaps theoretical physics and String Theory might just support such an exotic scenario, the scenario of the Braneworld.  

Question: Might 3-Braneworlds equal Parallel Universes (or in mystic-speak Astral Planes; Alternative Realities; Spirit Worlds; Parallel Realities; Higher Planes of Existence; Higher Dimensions; Portals in Space-time, as well as a host of related New Age claptrap phrases that non-New Age squares indeed call claptrap) from which come ‘higher beings’, ‘astral entities’, our ‘enlightened space brothers’ or even plain ordinary everyday run-of-the-mill aliens.  

You cannot have nebulous otherworldly beings, or alternate reality entities, without having an alternative place or reality or an otherworld(s) from which they come from visiting from and call home. Higher planes of reality and associated phrases have been called so much poppycock and confined to the rubbish bin, but perhaps prematurely.

Well, String Theory comes to the rescue, if not for the benefit of New Age gurus, then for cosmologists and theoretical physicists. But perhaps we can kill the two birds with the one stone as it were.

It all starts with String Theory. Now you probably think of the elementary particles, if you think of them at all, as very tiny little billiard balls. However, some bright sparks decades ago came up with an alternative. Instead of a zoo full of different types of little billiard balls, there were tiny vibrating strings. How they vibrated determined what kind of elementary particle it was – one good vibration/second might be an electron; two good vibrations/second a positron; three good vibrations/second equate to a neutrino, etc.

Strings could either be open (like an ordinary piece of string) or closed loops like a circle or ellipse; somewhat like a doughnut.

Now these strings are one-dimensional. But there can be two-dimensional Stringy objects, called Branes, short for Membranes. In fact, Branes became the generic name for all structures in String Theory, usually identified as p-Branes (weak pun) where the “p” stood for the number of spatial dimensions. So a 1-Brane was a string; a 2-Brane was a membrane; a 3-Brane was akin to our own version of reality. A 3-Brane is commonly referred to as a 3-Braneworld.

Oh, there’s a catch. In order for String Theory to theoretically work, there has to be extra dimensions (I can hear New Age mystics cheering now), in fact nine spatial dimensions all up, plus the one dimension we call time. So, in fact you could go all the way up to a 9-Brane. Again all p-Branes have an extra time dimension as well tagged on. All up, that’s six more spatial dimensions than we are comfortable with, but they tend to be out-of-sight and out-of-mind. Most extra dimensions are extremely tiny and curled up and hiding in-between the bits and pieces, the flotsam and jetsam of the quantum realm. But one extra dimension could be extremely large indeed providing the space all else, like 3-Braneworlds, is housed in.

Now 3-Braneworlds have to exist in higher dimensional space, like a 4-Brane which we can’t traverse. It’s just akin to how a fridge magnet is ‘trapped’ on a 2-D fridge surface (a 2-Brane plus extra time dimension) yet resides within a 3-D (3-Brane plus additional time dimension) space. Or, to use another analogy, a 2-D shower curtain hangs in 3-D space but the water droplets are confined to the 2-D shower curtain surface. We’re confined to a 3-D universe ‘surface’ (3-Braneworld plus one time dimension) but that resides in a 4-D (4-Brane plus one time dimension) volume. To cut to the chase, lets just call that what our spatial 3-Braneworld universe reside in a realm of five space-time dimensions. That realm has been given a name – it’s called the Bulk. Why it is called the Bulk I have no idea, but that’s what it is named.

I’ve notched the Bulk up to being a five dimensional space-time (out of a possible ten), but it could just as easily I guess be the tenth space-time dimension (9 spatial and one of time). It doesn’t really matter since we can’t directly see it, taste it, touch it, hear it or smell it, be it a 4-Brane or a 9-Brane. But regardless, the absolute key point is that gravity can connect 3-Braneworlds via the Bulk whether the Bulk has a 4-Brane, 5-Brane, 6-Brane, 7-Brane, 8-Brane or 9-Brane spatial dimensionality.

So much for the background theory: now, the interesting bit is what if our universe were in fact, in reality, really a 3-Braneworld (plus a single dimension of time) residing in 4-Brane spatial volume, or the equivalent, a five space-time dimensionality (the Bulk). What if in fact there were other 3-Braneworlds (each with a time dimension) residing in that same 4-Brane (plus time dimension) volume of five dimensional space-time (the Bulk). Because of that residing (or hiding) in a higher spatial dimension, two 3-Braneworlds could exist within millimeters of each other, unseen, separated by the Bulk. Why unseen? It’s back to those tiny open and closed strings and where they call home.

Closed strings are confined to our own 3-D or 3-Braneworld universe (like water droplets on that shower curtain) where they appear as those elementary particles that are associated with electromagnetism like photons and electrons, as well as those particles part and parcel to the strong and weak nuclear forces. These three forces are the quantum forces that rule our roost. If closed strings are the case for neighboring 3-Braneworlds, then we can’t see them because their electromagnetic (light) particles, photons, are forever confined and trapped to that 3-Braneworld and never reach us. Other 3-Braneworlds are invisible to us. That leaves the fourth force, the non-quantum force, gravity.

Open strings are the force particles of gravity, called gravitons. Open strings can exist with one string end attached to our 3-Braneworld, the other string end to an alien 3-Braneworld. Open strings, in other words, could cross the Bulk from our 3-Braneworld to another 3-Braneworld and be attached to both. In other words, gravity is our best bet means of detecting other nearby 3-Braneworlds. But you can’t see gravity, so our neighboring 3-Braneworld is for all practical purposes is still invisible to us. However, you can ‘see’ the effects that gravity has on objects you can see. You can’t see the gravity that controls the flight of a baseball, but you can see the effect of gravity on the baseball.

Postulating a nearby 3-Braneworld explains a trilogy of puzzlements. One is Dark Energy, one is Dark Matter; the other third is why gravity is so weak relative to the other three fundamental quantum forces (electromagnetism; weak and strong nuclear)

The Mystery of Dark Energy: If two 3-Braneworlds are in close proximity, attached by gravity, then they could have a close encounter of the ka-boom kind. We might term that ka-boom a ‘Big Bang’. If the Big Bang was an actual collision between two 3-Braneworlds (known as the Ekpyrotic Universe scenario), causing a ripple and expansion effect, then Dark Energy is that left over residual oomph, the continuing shock wave of the Big Bang which comes to the fore and dominates the Universe when the initial radiation dominated epoch and the following matter dominated epoch begin to thin out or dilute as the Universe expanded. In this scenario however, we have to have Dark Energy eventually thin out, dissipate and fade away too.

The Mystery of Dark Matter: In order to explain various rotational anomalies of the galaxy, ours and others, additional but unseen matter with associated gravity has got to exist – it’s either that or we have to drastically revise the laws of gravity as we currently understand them and no scientist is wiling to tilt at that windmill. Unfortunately, this postulated additional matter isn’t akin to normal matter which you can detect because you can see it. We can’t see this additional matter which is postulated, indeed nearly required, to exist. That’s why it is called ‘Dark Matter’, though a better term might be ‘invisible matter’. However, if a nearby 3-Braneworld universe shared its gravity with us, via those open graviton strings that transverse the Bulk, well that explains the ‘need for extra gravity’ to explain rotational anomalies and thus eliminates the need for the theoretical un-matter-like ‘Dark Matter’.

The Mystery of Weak Gravity: Gravity is the 98-pound weakling force relative to the trio of Charles Atlas quantum forces. Why has always been a total mystery that theoretical physicists have had to deal with. Open (gravity) strings in the Bulk explain why. Closed strings are confined to our own 3-Braneworld. We feel their full strength. However, our open string gravitons aren’t confined to our 3-Braneworld. Our gravity is diluted by spreading out into and throughout the Bulk and also attaching to other 3-Braneworlds. That’s why it’s the 98-pound weakling.

Another mystery is to answer the question, if our 3-Brane universe is expanding, what is it expanding into? Well, it’s expanding into that five space-time dimensional Bulk.  

To be continued…