Dark Matter Theory Challenged

There has been an interesting development in the world of Cosmology.  The theory of Dark Matter, was originally created, to account for the apparent lack of explanation, for the rotation speeds of Galaxies.

So the theory goes, galaxies rotate at a uniformed speed from centre to outer edges, which should only be possible, by our current understanding of gravity, if there were a lot more matter present in those galaxies, than is currently seen in stars, gas, planets etc.

However, the theory, is just that, a theory.  This is because, there has never been any detection of this dark matter (hence its name).  So until dark matter is observed, we are just surmising that it exists, based on observable effects, that could be caused by it.

However, there has been an alternative theory put forward in 1983, which is known as the Modified Newtonian Dynamics Theory (Mond).

This theory, has gained some interesting scientific backing, in that it better explains certain aspects of galaxy rotation.  But Dark Matter, still appears to be more complete, on all scales above and below that of the galaxy.

The BBC News, have published a news story covering the Mond issue.
This is about a paper that has been published discussing, the Mond - principle (that gravity effects will change, depending on how much matter is present and particularly in areas where its pull is very low.)

This is a huge departure from the universal theory, that forces such as gravity, strong, weak interactions etc, are constant in all parts of the universe.

I think I like Hawking's view of the universe.  He just accepts each new theory, not as a complete and final theory, but more as a useful tool, in the here and now, to explain observable phenomenon.  He terms himself as a positivist; being pragmatic and just working with the 'laws' that are available, rather than worrying, if they demonstrate the true nature of the universe.