I believe this is why super string theory asserts compactification of the extra dimensions. I do not however believe compactification is necessarily required: 5D Space-Time-Matter Consortium
Because the accelerating universe suggests a fluctuating (albeit over huge time intervals) ratio between dark energy and dark matter (cosmological constant (pdf)) - which significantly alters our concept of the age of the universe - I have become quite interested in yet another theory, the ekpyrotic model.
IMHO, the real quandary is why the dark energy we deduce from observation (astronomy) is not manifest in quantum mechanics!