Changes

==Methods of Observation==

==Methods of Observation==

Since 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. This indirect evidence is no less compelling than the evidence for, say, electrons, which cannot be seen, but are inferred from their electric field.  The evidence that a black hole provides is its extraordinarily strong gravity, which can be deduced from its effect on the motions of nearby stars. Stars that are near black holes, e.g. by being part of a binary star system that contains one, show wobbles in their orbits similar to the tidal effects of the moon on Earth’s oceans. Wobble effects, however, cannot be used to conclusively prove the existence of a black hole.<ref>http://library.thinkquest.org/C007571/english/advance/english.htm</ref><ref>''Black Holes'' by Heather Cooper and Nigel Henbest (book)</ref> Scientists have also observed stellar objects which have density consistent with black holes.<ref name="amazing-space.stsci.edu">http://amazing-space.stsci.edu/resources/explorations/blackholes/lesson/whatisit/history.html</ref>

Colliding black holes should produce gravitational waves, possible to detect experimentally. On 24 September 2015 the [[LIGO]] observatory made the first-ever successful observation of such event. <ref name="PRL-20160211">{{cite journal |author=Abbott, B.P. |title=Observation of Gravitational Waves from a Binary Black Hole Merger |url=http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102 |journal=[[Phys. Rev. Lett.]] |volume=116 |pages=061102 |year=2016 |doi=10.1103/PhysRevLett.116.061102 |display-authors=etal|arxiv = 1602.03837 |bibcode = 2016PhRvL.116f1102A }}</ref><ref name="NYT-20160211-db">{{cite news |last=Overbye |first=Dennis |authorlink=Dennis Overbye |title=Physicists Detect Gravitational Waves, Proving Einstein Right |url=http://www.nytimes.com/2016/02/12/science/ligo-gravitational-waves-black-holes-einstein.html |date=11 February 2016 |work=[[New York Times]] |accessdate=11 February 2016 }}</ref> The signal was consistent with theoretical predictions. The gravitational wave signal suggests that the separation of the two holes prior to merger was just 350&nbsp;km, hence they must be small in size, leaving black holes as the most plausible interpretation.

While matter and energy, even light, may not escape a black hole, Stephen Hawking has shown that when described by quantum mechanics, they should emit [[Hawking radiation]], which absent of an influx of mass-energy would lead to the evaporation of the black hole in a burst of gamma rays. Scientists are currently working to pick up one of these bursts, or the radiation itself, with any of several land- and space-based telescopes. However, the matter falling into black holes as well as the [[cosmic microwave background]] obscures the radiation and makes detection extremely difficult.

While matter and energy, even light, may not escape a black hole, Stephen Hawking has shown that when described by quantum mechanics, they should emit [[Hawking radiation]], which absent of an influx of mass-energy would lead to the evaporation of the black hole in a burst of gamma rays. This radiation may be possible to observe. However all results obtained to date remain unverified and debatable.<ref name="Milanoguys">{{cite journal|title=Hawking radiation from ultrashort laser pulse filaments |first1=F. |last1=Belgiorno |first2=S. L. |last2=Cacciatori |first3=M. |last3=Clerici |first4=V. |last4=Gorini |first5=G. |last5=Ortenzi |first6=L. |last6=Rizzi |first7=E. |last7=Rubino |first8=V. G. |last8=Sala |first9=D. |last9=Faccio |arxiv=1009.4634 |doi=10.1103/PhysRevLett.105.203901 |date=2010 |journal=Phys. Rev. Lett. |volume=105 |page=203901}}</ref><ref>{{cite news|title=Ultrafast Laser Pulse Makes Desktop Black Hole Glow|newspaper=[[Wired (magazine)|Wired]]|date=September 29, 2010|first=Lisa|last=Grossman|url=http://www.wired.com/wiredscience/2010/09/hawking-radiation-in-the-lab/|accessdate=April 30, 2012}}</ref>

 

 

'''Black holes''' are theoretical entities which cannot be directly observed and may not even exist.  Suggested by the debatable [[theory of relativity]] (see [[Counterexamples to Relativity]]), black holes are postulated to be collapsed objects, usually [[stars]], which have supposedly become so [[dense]] that within a certain radius their [[escape velocity]] exceeds the [[speed of light]]. Thus, they absorb all matter and energy within that radius.  Light and matter can enter, but nothing can ever escape.  '''''Black holes are a [[sacred cow]] of [[atheistic science]]'''''.

 

Black holes are increasingly promoted by [[liberal]] publications, such as the science page of the ''[[New York Times]]'', glossy magazines, and the movies the ''Event Horizon'' (1997), ''The Black Hole'' (TV, 2006), and ''Interstellar'' (2014). As with the related theoretical concept of a "[[wormhole]]",<ref name="nytimes.com">The prediction of the existence of wormholes, and its naming in 1957, predates the prediction and naming (1967) of a black hole.[http://www.nytimes.com/2008/04/14/science/14wheeler.html?pagewanted=print]</ref> it is impossible to prove that no black hole exists anywhere, and thus they fail the [[falsifiability]] requirement of science.  

 

Because of quantum-mechanical phenomena involving Hawking Radiation, discussed later in the article, black holes must emit radiation and thus are a logical contradiction at the microscopic level.

 

Black holes have never been directly observed, and there is no direct evidence for their existence. Even believers in black holes should admit that there are far fewer than predicted by theory, and they lose credibility when they fail to address that undisputed truth. They will cite evidence of observations of radiation from accretion disks, motion of stars near the center of the galaxy, and "gravitational lensing", having all the properties that relativity predicts, around places where there are no visible objects. Like positrons, their existence was predicted (in both cases based on relativity) before there was any actual evidence of their existence.

 

Black holes are assumed to come into existence from extremely large stars that collapse into a state of high density when they run out of fusion fuel. An object becomes a black hole when it lies entirely inside the Schwarzschild radius (see below) determined by its mass. For most objects, the Schwarzschild radius is very tiny compared with its size (for Earth it is about 1 centimeter), so the object does not lie inside that radius.

 

Black holes are conceptually associated with "[[wormhole]]s",<ref name="nytimes.com"/> which never caught on with the public, perhaps due to its poor terminology.

==History of the idea==

==History of the idea==