http://www.space.com/33850-weird-gal...rk-matter.htmlAstronomers have discovered a galaxy as big as the Milky Way that consists almost entirely of dark matter, a mysterious and invisible substance that scientists have been trying to figure out for decades. Only one-hundredth of one percent of the galaxy is ordinary, visible matter like stars and planets. The other 99.99 percent of the stuff in this galaxy can't be seen.
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I think this is a landmark discovery. Not only will this galaxy allow us to finally get to study dark matter in the most "pure" form we have been able to so far, but it also raises quite a few questions on what other constructs made primarily, or even entirely, of dark matter we are missing. Perhaps the variety of macroscopic objects in the Universe is much higher than we have previously thought!