Greetings, I've never liked the idea of Quintessence (although I admit I don't understand it fully). 1. As for Dark energy, what are the leading theories on how it may be caused? 2. Also, I have an idea about a possible cause for the Universe's acceleration. Perhaps, the fringes of the Universe are of such a great density that they gravitationally pull the Universe outwards. Can you criticize this basic concept? I'd like to know why this theory could not be true according to known physics, please tear it apart. Thanks. P.S. Zapper stay away!