Accelerating Universe and Event Horizon
Abstract
It has been argued in the literature that if a universe is expanding with an accelerating rate indefinitely, it presents a challenge to string theories due to the existence of event horizons. We study the fate of a currently accelerating universe. We show that the universe will continue to accelerate indefinitely if the parameter $\omega = p/\rho$ of the equation of state is a constant, no matter how many different types of energy (matter, radiation, quintessence, cosmological constant and etc) are contained in the universe. This type of universe will always exhibit an event horizon indicating that such a universe may not be derived from string theories. We also comment on some related issues.
 Publication:

arXiv eprints
 Pub Date:
 April 2001
 arXiv:
 arXiv:astroph/0105005
 Bibcode:
 2001astro.ph..5005H
 Keywords:

 Astrophysics;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 9 pages, Latex, no figures. A discussion on the recent data from observations of SN 1997ff is included