We humans experience our universe in three dimensions, yet superstring theory claims there are 10 dimensions ~ nine spatial ones plus a dimension of time. Now some Japanese scientists think they may have an explanation for how a three-dimensional universe emerged from the original nine dimensions of space.
According to Discovery.com:
According to string theorists, there are the three full-sized spatial dimensions we experience every day, one dimension of time, and six extra dimensions crumpled up at the Planck scale like itty-bitty wads of paper. As tiny as these dimensions are, strings ~ the most fundamental unit in nature, vibrating down at the Planck scale ~ are even smaller.
The geometric shape of those extra dimensions helps determine the resonant patterns of string vibration. Those vibrating patterns in turn determine the kind of elementary particles that are formed, and generate the physical forces we observe around us, in much the same way that vibrating fields of electricity and magnetism give rise to the entire spectrum of light, or vibrating strings can produce different musical notes on a violin.
All matter (and all forces) are composed of these vibrations -- including gravity. And one of the ways in which strings can vibrate corresponds to a particle that mediates gravity.
Scientists believe string theory could be used to explore the infinitely tiny point of our universe's birth.