The fate of dark energy

By studying the present cosmological data, particularly on CMB, SNeIA and LSS, we find that the future fate of the universe, for simple linear models of the dark energy equation-of-state, can vary between the extremes of (I) a divergence of the scale factor in as little as 7 Gyr; (II) an infinite lifetime of the universe with dark energy dominant for all future time; (III) a disappearing dark energy where the universe asymptotes as t --> infinity to a (t) similar to t(2/3), i.e., matter domination. Our dreadful conclusion is that no amount of data from our past light-cone can select between these future scenarios. (C) 2003 Published by Elsevier Science B.V.