Freethinkers D Brane Theory.

Freethinkers D Brane Theory.. This has implications for physical cosmology. Because string theory implies that the Universe has more dimensions than we expect 26 for bosonic string theories and 10 for superstring theories we have to find a reason why the extra dimensions are not apparent. One possibility would be that the visible Universe is in fact a very large D-brane extending over three spatial dimensions. Material objects, made of open strings, are bound to the D-brane, and cannot move "at right angles to reality" to explore the Universe outside the brane. This scenario is called a brane cosmology. Interestingly, the force of gravity is not due to open strings; the gravitons which carry gravitational forces are vibrational states of closed strings. Because closed strings do not have to be attached to D-branes, gravitational effects could depend upon the extra dimensions at right angles to the brane. (This is a fairly simple braneworld model. More recent innovations under close study as of 2020 are more intricate, but this discussion reflects some of their spirit.)