I guess it depends on your definition of 'seen'. Certainly the evidence is very unambiguous: http://blogs.discovermagazine.com/cosmicvariance/2006/08/21/dark-

I guess it depends on your definition of 'seen'. Certainly the evidence is very unambiguous: http://blogs.discovermagazine.com/cosmicvariance/2006/08/21/dark-matter-exists/ http://blogs.discovermagazine.com/cosmicvariance/2006/08/21/...