Dark-Matter Galaxy X

IMAGE SOURCE - http://antwrp.gsfc.nasa.gov



An invisible Dark-Matter "Galaxy X" just outside our own. The invisibility of "Galaxy X"—as the purported body has been dubbed—may be due less to its apparent status as a dwarf galaxy than to its murky location and its overwhelming amount of dark matter, astronomer Sukanya Chakrabarti speculates.
Detectable only by the effects of its gravitational pull, dark matter is an invisible material that scientists think makes up more than 80 percent of the mass in the universe.

Chakrabarti, of the University of California, Berkeley, devised a technique similar to that used 160 years ago to predict the existence of Neptune, which was given away by the wobbles its gravity induced in Uranus's orbit.
Based on gravitational perturbations of gases on the fringes of our Milky Way galaxy, Chakrabarti came to her conclusion that there's a heretofore unknown dwarf galaxy about 260,000 light-years away.

READ MORE/ SOURCE - http://news.nationalgeographic.com/news/2011/01/110114-galaxy-x-space-dark-matter-dwarf-satellite-science-chakrabarti/