These are excerpts and elaborations from my book "The Nature of Consciousness"
Branes Another
important implication is that our universe might not be all that there is. The
electron uses only three of the available dimensions (the so called “Dirichlet
membrane” or “D-brane”), and our universe may simply be confined to those three
dimensions, but the other dimensions might be “filled” with something else. D-branes were
discovered by the US physicist Joseph Polchinski ("New Connections Between String Theories", 1989) and
the Czech physicist Petr Horava ("Strings on world-sheet orbifolds", 1989). They are
mathematical objects that resemble membranes in a five-dimensional spacetime.
Our universe could in fact be a D-brane extending over the three familiar spatial
dimensions. The objects of our world could be stuck to this D-brane like bugs
on flypaper. Hence the illusion of three dimensions. If elementary
particles are indeed the different modes of vibration of strings, Polchinski (“Dirichlet Branes and Ramond-Ramond
Charges“, 1995) realized that these strings are attached to “D-branes”, a
finding that triggered the so called “Second Superstring Revolution” of
M-theory and Holographic Theory. There might be
countless branes around. Each brane contains its own particles, including
bosons (i.e., its own portfolio of forces). Ordinary particles are vibrational
modes of open strings, strings that are confined to a brane. The particles of a
brane are most likely insensitive to the forces that prevail in some other brane.
For example, the particles of our brane are sensitive to electromagnetism but
not to the many other kinds of force that may exist in many other branes; and,
viceversa, the particles of other branes are most likely insensitive to
electromagnetism. The higher dimensional space is a sort of mega-brane,
containing its own particles and forces. The graviton is the vibrational mode
of a closed string, not an open one. It is not confined to branes. It is one of
those particles that exist in the higher dimensional space and can therefore
communicate with the particles confined into lower-dimension branes. Gravity is
a force (the only force?) that is not confined to a brane. The reason that
gravity appears to us (inside our brane) so intrinsically different from the
other forces is that… it is. When it comes to
our world, we live in a three-dimensional space in which the Standard Model
rules. Gravity lives in the higher-dimensional brane. Gravity can travel to our
membrane, but it arrives considerably weakened, and that is why it is much
weaker than the other forces. The larger the extra dimensions are, the weaker
the force that originates from them when perceived inside a brane. Back to the beginning of the chapter "The New Physics" | Back to the index of all chapters |