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[[Image:DarkMatterNASA1.jpg|350px|right]]'''Dark matter''', in [[astronomy]], is any hypothetical [[matter]] that is not directly detectable but which astronomers infer when the actual mass of any observed celestial object is not sufficient to account for an observed gravitational effect. It is one of two concepts (the other is [[dark energy]]) that conventional astronomers invoke to account for observations that conventional cosmologies, including the [[Big Bang]], cannot explain.  

[[Image:DarkMatterNASA1.jpg|350px|right]]'''Dark matter''', in [[astronomy]], is any hypothetical [[matter]] that is not directly detectable but which astronomers infer when the actual mass of any observed celestial object is not sufficient to account for an observed gravitational effect. It is one of two concepts (the other is [[dark energy]]) that [[evolution]]istic astronomers invoke to account for observations that old-[[universe]] cosmologies, including the [[Big Bang]], cannot explain.

== The first dark matter ==

== The first dark matter ==

Then in 1915, [[Albert Einstein]] solved the problem. He showed that Mercury, at [[apsis|perihelion]], passes close enough to the Sun for [[General Relativity]] to require a second-order correction. He published the correction and accounted exactly for the precession in the orbit of Mercury, without the need for any planet, [[asteroid]] belt, or other object or objects inside that orbit.<ref name=Hartnett>Hartnett, John. ''[[Starlight, Time and the New Physics]]''. Creation Book Publishers, 2007. ISBN 9780949906687.</ref>

Then in 1915, [[Albert Einstein]] solved the problem. He showed that Mercury, at [[apsis|perihelion]], passes close enough to the Sun for [[General Relativity]] to require a second-order correction. He published the correction and accounted exactly for the precession in the orbit of Mercury, without the need for any planet, [[asteroid]] belt, or other object or objects inside that orbit.<ref name=Hartnett>Hartnett, John. ''[[Starlight, Time and the New Physics]]''. Creation Book Publishers, 2007. ISBN 9780949906687.</ref>

== Modern conventional concept ==

== The current problem ==

[[Image:Sky wmap.jpg|100px|left]]The present concept of dark matter dates from the 1930's, when astronomers first found serious differences between the masses they inferred by examining orbital speeds and the masses they inferred by measuring stellar, galactic, and other visual magnitudes.

[[Image:Sky wmap.jpg|100px|left]]The current problem involving a mass deficit in astronomical observations has been known since the 1930's, when astronomers first found serious differences between the masses they inferred by examining orbital speeds and the masses they inferred by measuring stellar, galactic, and other visual magnitudes. The classic gravitational equation, derived from the theory of [[gravity]] of Sir [[Isaac Newton]], gives the total dynamical mass in any system that is inside the orbit of any given body (for example, a particular star in its galaxy):

 

=== The mathematical problem ===

This classic equation, derived from the theory of [[gravity]] of Sir [[Isaac Newton]], gives the total dynamical mass in any system that is inside the orbit of any given body (for example, a particular star in its galaxy):

<math>M = \frac{v^{2}R}{G}</math>

<math>M = \frac{v^{2}R}{G}</math>

[[Image:HubbleDarkMatterRing.jpg|thumb|300px|left|Image of galactic cluster with ring of alleged dark matter around it]]Since that time, astronomers have assumed that some form of matter, which gives off no measurable radiation, is nevertheless present in various galaxies and galactic clusters that clearly spin faster than their measured luminous masses would predict.<ref name=Harvard>Authors unknown. "[http://xrtpub.harvard.edu/xray_astro/dark_matter.html Dark Matter Mystery]." ''Field Guide to X-ray Astronomy'', Chandra X-ray Center, Harvard University, Cambridge, MA, August 29, 2006. Accessed July 28, 2008.</ref> They acknowledge, however, that the notion of a new, non-luminous form of matter is difficult to accept. Yet many astronomers insist that they have observational evidence for which dark matter remains the only plausible explanation. One such communication comes from the Chandra X-ray Center, whose astronomers stated in 2006 that they had observed two galactic clusters for hundreds of hours, and that each one clearly showed a rotational speed consistent with far more mass than was visible.<ref name=Chandra>Hupp E, Roy S., and Watzke M. "[http://www.nasa.gov/home/hqnews/2006/aug/HQ_06297_CHANDRA_Dark_Matter.html NASA Finds Direct Proof of Dark Matter]." [[NASA]], press release 06-297, August 21, 2006. Accessed July 28, 2008.</ref>

[[Image:HubbleDarkMatterRing.jpg|thumb|300px|left|Image of galactic cluster with ring of alleged dark matter around it]]Since that time, astronomers have assumed that some form of matter, which gives off no measurable radiation, is nevertheless present in various galaxies and galactic clusters that clearly spin faster than their measured luminous masses would predict.<ref name=Harvard>Authors unknown. "[http://xrtpub.harvard.edu/xray_astro/dark_matter.html Dark Matter Mystery]." ''Field Guide to X-ray Astronomy'', Chandra X-ray Center, Harvard University, Cambridge, MA, August 29, 2006. Accessed July 28, 2008.</ref> They acknowledge, however, that the notion of a new, non-luminous form of matter is difficult to accept. Yet many astronomers insist that they have observational evidence for which dark matter remains the only plausible explanation. One such communication comes from the Chandra X-ray Center, whose astronomers stated in 2006 that they had observed two galactic clusters for hundreds of hours, and that each one clearly showed a rotational speed consistent with far more mass than was visible.<ref name=Chandra>Hupp E, Roy S., and Watzke M. "[http://www.nasa.gov/home/hqnews/2006/aug/HQ_06297_CHANDRA_Dark_Matter.html NASA Finds Direct Proof of Dark Matter]." [[NASA]], press release 06-297, August 21, 2006. Accessed July 28, 2008.</ref>

=== Estimated proportion ===

=== Estimated proportion ===

[[Image:Cosmos percent comp.jpg|200px|right]]The Wilkinson Microwave Anisotropy Probe (WMAP) team at [[NASA]] has used measurements of cosmic microwave background radiation<ref name=WMAP>Hinshaw GF, and Griswold, B. "[http://map.gsfc.nasa.gov/news/index.html WMAP Mission Results]." [[NASA]], April 17, 2008. Accessed July 26, 2008.</ref> to determine that the universe is geometrically flat. According to standard cosmology, the universe should then be at a critical mass density of 9.9 * 10^-27kg/m³. The actual mass density of the universe is more than twenty times less than that.<ref name=WMAP2>Hinshaw GF, and Griswold B. "[http://map.gsfc.nasa.gov/universe/uni_matter.html WMAP - Content of the universe]." [[NASA]], April 17, 2008. Accessed July 28, 2008.</ref>

[[Image:Cosmos percent comp.jpg|200px|right]]The Wilkinson Microwave Anisotropy Probe (WMAP) team at [[NASA]] has used measurements of cosmic microwave background radiation<ref name=WMAP>Hinshaw GF, and Griswold, B. "[http://map.gsfc.nasa.gov/news/index.html WMAP Mission Results]." [[NASA]], April 17, 2008. Accessed July 26, 2008.</ref> to determine that the universe is geometrically flat. According to standard cosmology, the universe should then be at a critical mass density of 9.9 * 10^-27kg/m³. The actual mass density of the universe is more than twenty times less than that.<ref name=WMAP2>Hinshaw GF, and Griswold B. "[http://map.gsfc.nasa.gov/universe/uni_matter.html WMAP - Content of the universe]." [[NASA]], April 17, 2008. Accessed July 28, 2008.</ref>

Current theory suggests that the familiar baryonic matter (composed of atoms) constitutes only 4.6% of the total mass-energy in the universe. Dark matter constitutes 23% of the total, while [[dark energy]] comprises the remaining 72%.<ref name=WMAP2/>

Current theory suggests that the familiar baryonic matter (composed of atoms) constitutes only 4.6% of the total mass-energy in the universe. Dark matter constitutes 23% of the total, while [[dark energy]] comprises the remaining 72%.<ref name=WMAP2/>

=== Candidates for dark matter ===

=== Proposed explanations for dark matter ===

Conventional astronomers have generally focused on the following explanations for the discrepancy between dynamical and luminous mass:

Evolutionistic astronomers have generally focused on the following explanations for the discrepancy between dynamical and luminous mass:

# Brown dwarf [[star]]s and similarly massive but relatively non-luminous objects. Astronomers have in fact invented a new name for a class of objects that include brown dwarf stars and other massive objects: Massive Compact Halo Objects, or MACHOs.<ref name=Silk/><ref name=Miller/><ref name=WMAP2/><ref name=White>White, Martin. "[http://astro.berkeley.edu/~mwhite/darkmatter/dm.html Dark Matter]." Department of Astronomy, University of California at Berkeley, Berkeley, California, ca. 1995. Accessed July 28, 2008.</ref>

# Brown dwarf [[star]]s and similarly massive but relatively non-luminous objects. Astronomers have in fact invented a new name for a class of objects that include brown dwarf stars and other massive objects: Massive Compact Halo Objects, or MACHOs.<ref name=Silk/><ref name=Miller/><ref name=WMAP2/><ref name=White>White, Martin. "[http://astro.berkeley.edu/~mwhite/darkmatter/dm.html Dark Matter]." Department of Astronomy, University of California at Berkeley, Berkeley, California, ca. 1995. Accessed July 28, 2008.</ref>

# Supermassive [[black hole]]s. Astronomers are now attempting to detect these objects by their relativistic effects on light, in which they act as lenses.<ref name=WMAP2/>

# Supermassive [[black hole]]s. Astronomers are now attempting to detect these objects by their relativistic effects on light, in which they act as lenses.<ref name=WMAP2/>

Tim Thompson<ref name=Thompson/> has recently suggested yet another possibility to which most conventional astronomers pay scant attention. He suggests that the major attractive force that allows galaxies and systems of higher mass to rotate with such excessive speed is not gravity at all, but electrostatic forces. He reminds his readers that electrostatic forces are stronger than gravity, and also that the strength of a magnetic field varies inversely as the first power, not the square, of the distance from the center. This is very close to Milgrom's MOND, with the advantage of having an underlying theory to explain it,<ref name=Thompson/> which Milgrom's system does not have.<ref name=Hartnett/>

Tim Thompson<ref name=Thompson/> has recently suggested yet another possibility to which most conventional astronomers pay scant attention. He suggests that the major attractive force that allows galaxies and systems of higher mass to rotate with such excessive speed is not gravity at all, but electrostatic forces. He reminds his readers that electrostatic forces are stronger than gravity, and also that the strength of a magnetic field varies inversely as the first power, not the square, of the distance from the center. This is very close to Milgrom's MOND, with the advantage of having an underlying theory to explain it,<ref name=Thompson/> which Milgrom's system does not have.<ref name=Hartnett/>

Don DeYoung challenged the notion of dark matter as a fanciful concept with little justification.<ref name=deYoung/> He pointed out that none of the conventional explanations popular at the time were satisfactory:

In 2000, Don DeYoung, writing in the [[Creation Research Society Quarterly]], challenged the notion of dark matter as a fanciful concept with little justification.<ref name=deYoung>DeYoung DB. "[http://www.creationresearch.org/crsq/articles/36/36_4/darkmatter.html Dark Matter]." ''Creation Research Society Quarterly'', 36(4), March 2000. Accessed July 28, 2008.</ref> He pointed out that none of the conventional explanations popular at the time were satisfactory:

# Non-luminous stars, the usual candidates for MACHOs, would have to be far more common than they actually are, by several orders of magnitude, for them to account for the mass deficit.

# Non-luminous stars, the usual candidates for MACHOs, would have to be far more common than they actually are, by several orders of magnitude, for them to account for the mass deficit.

# Black holes are a theoretical construct that have not thus far been verified.

# Black holes are a theoretical construct that have not thus far been verified.

DeYoung also challenged the notion that galaxies or galactic clusters were necessarily stable. He did not comment directly on Milgrom's modified dynamic, but he did suggest that gravity was poorly understood.

DeYoung also challenged the notion that galaxies or galactic clusters were necessarily stable. He did not comment directly on Milgrom's modified dynamic, but he did suggest that gravity was poorly understood.

== References ==

== References ==