## Introduction

The

5-dimensional warped geometery theory is a

braneworld theory developed by physicist

Lisa Randall and

Raman Sundrum while trying to solve the

hierarchy problem of the

Standard Model. This model is called

RS-1 in the physics community. It involves a finite five-dimensional

bulk that is extremely warped and contains two

branes: the Gravitybrane (where gravity is a relatively strong force; also called "Planckbrane") and the Weakbrane (our home with the Standard Model particles; also called "Tevbrane"). In this model, the two branes are separated in the not-necessarily large fifth dimension by approximately 16 units (the units based on the brane and bulk energies). The Gravitybrane has positive brane energy, and the Weakbrane has negative brane energy. These energies are the cause of the extremely warped

spacetime. Note that this article doesn't go fully into the theory; if you want more, check out Lisa Randall's book:

Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions. Or, see the

Randall-Sundrum model article for a technical explanation.

## Graviton Probability Function

In this warped spacetime that is

only warped along the fifth dimension, the

graviton's

probability function is extremely high at the Gravitybrane, but it drops exponentially as it moves closer towards the Weakbrane. In this, gravity would be much weaker on the Weakbrane than on the Gravitybrane.

## Growing, Shrinking, and Changing Weight: Solving the Hierarchy Problem

Also in this model, any objects moving from the Gravitybrane to the Weakbrane in the bulk would be growing, becoming lighter, and moving more slowly through time. Distance and time expand near the Weakbrane, and mass and energy shrink near it. This creates an alternate explanation of gravity's weakness in the Weakbrane: everything is lighter. An interesting part of this is that the hierarchy problem is automatically solved. The main scale on the Gravitybrane would be the

Planck scale. However, the change by 16 units causes the scales to change by 16 orders of magnitude. On the Gravitybrane, strings would be 10

^{-33} cm in size, but on the Weakbrane they'd be 10

^{-17} cm. In fact, this makes the mass scale for the Weakbrane based on about a TeV. Therefore, you no longer have the strange range of masses and energies. If this is the case, we should see evidence when the

Large Hadron Collider begins working.

## Bibliography

Lisa Randall,

Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions, HarperCollins, 2005, ISBN 0-06-053108-8