I'm sure that someone here is clever enough to find a reason to be reassured by the following paper (highly recommended by Jerry, though): "Dark matter, dark energy and modern cosmology: the case for a Kuhnian paradigm shift" by J. E. Horvath.

http://arxiv.org/PS_cache/arxiv/pdf/...809.2839v1.pdf

There is no firm hint from measured physics about ”dark matter” or ”dark energy” particles as yet, and their existence would open up a whole new physics deeply affecting the existing view of the microphysical world. The fact that, according to this possibility, we may be ignoring the composition of > 95% of our universe, and the implication that we are not made of the same material that most of the universe can not be overstated.

Instead, we may be well inside a true major scientific revolution in cosmology itself, and thus our vision of the problem still blurred because precisely of that. This would be the case if full revision of the way we look at gravitational physics may be needed (hopefully making dark matter + dark energy go away), as advocated by some.