How To Open & Close Portals

Lisa Randall spoke with Smithsonian in December 2011 about her book Knocking on Heaven's Door. In the book, the physicist presents the idea of "an extra dimension that's so warped" it answers scientific questions about the strange mass-to-size ratio of particles. Theoretically, this dimension boasts both weak and strong pockets of gravity that affect the different particles, making their mass smaller than expected in our dimension. 
The particles supposedly use momentum to travel through the other dimension and back into this one without being seen by the naked eye. This could explain, at least scientifically, how portals open with strong energies.