from the now-you-don't-see-it-and-now-you-still-don't? dept.
I happened upon a very readable and thought-provoking article on dark matter and thought others might find it interesting, too.
Dark matter is the commonest, most elusive stuff there is. Can we grasp this great unsolved problem in physics?
The past success of standard paradigms in theoretical physics leads us to hunt for a single generic dark matter particle -- the dark matter. Arguably, though, we have little justification for supposing that there is anything to be found at all; as the English physicist John D Barrow said in 1994: 'There is no reason that the universe should be designed for our convenience.' With that caveat in mind, it appears the possibilities are as follows. Either dark matter exists or it doesn't. If it exists, then either we can detect it or we can't. If it doesn't exist, either we can show that it doesn't exist or we can't. The observations that led astronomers to posit dark matter in the first place seem too robust to dismiss, so the most common argument for non-existence is to say there must be something wrong with our understanding of gravity -- that it must not behave as Einstein predicted. That would be a drastic change in our understanding of physics, so not many people want to go there. On the other hand, if dark matter exists and we can't detect it, that would put us in a very inconvenient position indeed.