## 5. The perturbed equation of motion-energyWe start with the equation of motion The electromagnetic contribution is as in Eq. (11) but now taking into account . We now obtain which yields for the 0th component which is the equation of energy conservation. For the However, it is possible to show that . This comes from the well known property of the tensor metric , and therefore and , which becomes in our case where now corresponds to the Robertson-Walker metric. We have With this simplification and some algebra, we have for the which is the equation of motion. © European Southern Observatory (ESO) 1997 Online publication: April 20, 1998 |