Please correct any misunderstandings I may have in the following:
* Vacuum has no mass (gravitational attraction).
* Normal matter has mass.
* Vacuum is composed of matter and antimatter.
* Therefore, antimatter has negative mass (negative gravitational attraction).
* Vacuum has no mass (gravitational attraction). * Normal matter has mass. * Vacuum is composed of matter and antimatter. * Therefore, antimatter has negative mass (negative gravitational attraction).