The Nobel Prize in Physics 2011 was awarded for the work on "the discovery of the accelerating expansion of the Universe through observations of distant supernovae", as this discovery was like 'applying the brakes on a car', giving us insights into universe’s evolution and possibly its ultimate fate.
Yet, the driving force behind the acceleration is unknown; it is guessed as vacuum energy (in this context called dark energy). In Particle Physics, there are two candidates for this vacuum energy, the quantum fluctuations and the spontaneous symmetry breaking. Another idea is about an inflationary phase in the early Universe, breaking certain symmetries, spontaneously generating a time-dependent, huge vacuum energy density that during a very short time made the Universe expand enormously. A similar effect may still be at work as the force for this accelerating expansion of the universe.
In fact, the fact that this universe is expanding with acceleration was predicted in the book “Super Unified Theory” (ISBN 0-916713-02-4, Copyright # TX 1-323-231, Library of Congress Catalog Card Number 84-90325); it wrote, “During the expansion period, the space of the universe increased when the time goes forward, ¼ of the time quanta’s energy goes into space (vacuum) which acts as an energy bank. … all mass (energy) of the universe is coming from the time [quanta]. … Therefore, when the big bang momentum was exhausted out by the gravity, the space expansion will slow down. And, the density of this universe will increase slowly (3/4 of time’s energy goes into matter) and finally reach the critical density.” (Chapter 5 --- The future of the universe, page 42).
In the article "Initial Condition of Universe" (written in 1994, available at http://www.prequark.org/Initial.htm ), it wrote, "Why shall and how can space expand? The space expansion is the essence of this new physics, described with Equation Zero. The bouncing between real and ghost time creates 64 subspaces. A quarter of these 64 subspaces are true space, pure vacuum. Three quarter of these 64 subspaces are particles, baryonic matter. So, when time is bouncing forward, the space is expanded, and matter is created. In short, the Big Bang is not an isolated single event in the long ago history of our universe but is only a beginning of a continuous process."
The above passages clearly states that the force drives the expanding universe (in addition to the initial big bang momentum) is the “time quanta energy”. Up to now (October 8, 2011), time is not viewed as quanta by the mainstream physics community. Yet, “time quanta” is the essence in the “Super Unified Theory (SUT).” Not only is the accelerating expansion of the universe the direct consequence of time quanta (SUT), but also are the roots for the theoretical calculation of alpha (the electron fine structure constant, http://prebabel.blogspot.com/2011/05/higgs-boson-bad-idea-part-four.html ) and the theoretical foundation for Prequark Chromodynamics (http://www.prequark.org/ ).
In fact, many theories (including wrong theories) can predict an accelerating expansion of the universe. In SUT, the prediction of an accelerating expansion of the universe is only a small part in a big framework. The validity of that prediction does not rely on any direct observation (such as the works of Saul Perlmutter, Brian Schmidt and Adam Riess) but rely on the validity of the entire framework, the theoretical calculation of alpha, the Prequark Chromodynamics, etc..