Evidence for black holes

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Category: Science News Archive (2010)
Sgr A*, several of which approach Sgr A* to within tens of light hours. Measurements have also established one complete orbit of a star named S2, which moves in a highly elliptical orbit with a period of 15.8 years. These details of stellar dynamics imply that a concentrated mass of about four million solar masses is located at the position of Sgr A*.Genzel and colleagues argue, this provides almost compelling evidence for the existence of an astrophysical black hole in our Galaxy. However, logically it establishes only the existence of a very massive compact object of unknown kind, which must be a black hole only if there's no other thing it might conceivably be. And there are possibilities. ...
httpwww.nature.com/nphys/journal/v6/n12/full/nphys1878.html