It's things like galaxies with quadrillions of times the mass of our sun colliding that make me remember just how small a piece of the universe we are. It's awesome that they got to see that... And identify some dark matter in the process!
This article seems to suffer from even more than the usual level of "The author has no clue about the science" Syndrome, especially the bits about gravitational lensing.<p>Now, I thought that galaxies were so sparse that most of the interactions two "colliding" galaxies would have would be gravitational (rather than an actual collision). In this case, the finding would <i>seem</i> to imply that dark matter isn't affected by gravity the same way, which would be <i>darned weird</i>.