http://blogs.discovermagazine.com/badast...hubble-picture/

Black holes are "unseen" the same way the wind is. Just because you can't see it, doesn't mean you can't observer its effects on the things around it. And falls fully under the definition Peter provided above.


Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris