Changes

==Methods of Observation==

==Methods of Observation==

Black holes are literally invisible by traditional means of observation (that is, emission or reflection of some sort of radiation) and so cannot be directly observed, their nature is determined by other means. That said however, as particles near the event horizon their velocity increases and particles are drawn closer and closer together resulting in friction which caused a radioactive accretion disc which can be observed on the electromagnetic spectrum not visible to the eye.<ref>https://www.physicsoftheuniverse.com/topics_blackholes_event.html</ref>

Black holes are literally invisible by traditional means of observation (that is, emission or reflection of some sort of radiation) and so cannot be directly observed, their nature is determined by other means. That said however, as particles near the event horizon their velocity increases and particles are drawn closer and closer together resulting in friction which caused a radioactive accretion disc which can be observed on the electromagnetic spectrum not visible to the eye.<ref>https://www.physicsoftheuniverse.com/topics_blackholes_event.html</ref><ref>{{cite journal

  |last1=Gillessen |first1=S.

  |last1=Gillessen |first1=S.

  |last2=Eisenhauer |first2=F.

  |last2=Eisenhauer |first2=F.

  |bibcode=2009ApJ...692.1075G

  |bibcode=2009ApJ...692.1075G

  |ref=harv

  |ref=harv

}}</ref> Since 1995, astronomers have tracked the motions of 90 stars orbiting an invisible object coincident with the radio source in the center of our galaxy, Milky way. The astronomers were able to infer that a 2.6 million sollar mass object must be contained within the radius of 0.02 [[light-year]]s to cause the motions of those stars.<ref name="Ghez1998">{{cite journal

}}</ref> Since 1995, astronomers have tracked the motions of 90 stars orbiting an invisible object coincident with the radio source in the center of our galaxy, Milky way. The astronomers were able to infer that a 2.6 million sollar mass object must be contained within the radius of 0.02 [[light-year]]s to cause the motions of those stars.<ref name="Ghez1998">{{

  |last1=Ghez |first1=A. M.

  |last1=Ghez |first1=A. M.

  |last2=Klein |first2=B. L.

  |last2=Klein |first2=B. L.