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Line 83: − + − Conventional cosmologists estimate that 70 percent of the total energy in the universe consists of dark energy.<ref name=Williams/> [[Dark matter]] occupies another 25 percent. The remaining portion is the familiar, or baryonic matter of which all objects are made.<ref name=nasa1/>+ Line 22:
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Line 119: − − ==Young Earth Creation Science View== − Dr. [[Walt Brown]] wrote about the concept of dark energy the following: − {{cquote|Neither “dark matter” (created to hold the [[universe]] together) nor “dark energy” (created to push the universe apart) has been seen or measured. We are told that “most of the universe is composed of invisible dark matter and dark energy.” Few realize that both mystical concepts were devised to preserve the [[big Bang theory|big bang theory]].<ref>http://www.creationscience.com/onlinebook/AstroPhysicalSciences16.html</ref>}} − − Dark energy is a mathematical convenience. Some authorities admit that it may never be detectable. One reason why no one would ever detect it is that it represents an error. Conventional cosmologists have admitted that dark energy might represent an error of their understanding of gravity. Creationists suggest that the error is far more fundamental. − − [[John Hartnett]], in ''[[Starlight, Time and the New Physics]],''<ref name=Hartnett>Hartnett, John. ''[[Starlight, Time and the New Physics]]''. Creation Book Publishers, 2007. ISBN 9780949906687.</ref> reminds his readers that Moshe Carmeli first formed a new model, called [[cosmological relativity]], and through this model predicted that the universe would in fact appear to be accelerating. He made this prediction in 1996, ''two years before'' the publication of the Type Ia supernova data and the introduction of the idea of "dark energy" into cosmological discussions. In making this prediction, Carmeli ''did not'' invoke either dark energy or dark matter. − − The astronomers of the Supernova Cosmology Project and the High-Z Supernova Search Team did not use Carmeli's model, but instead relied upon the Friedmann-Lemaître cosmological model. That model could not fit the observations without the invocation of dark matter, to account for galaxies spinning too rapidly for Newtonian gravity to hold them together, and dark energy, to account for the observed acceleration of universal expansion. − − Hartnett continued Carmeli's calculations and applied them to the explicit statements in the [[Bible]] concerning the universe' beginnings. The Bible says that [[God]] created an expanse of space and then, on Day Four of creation, stretched it out very rapidly. Thus the most distant objects would show evidence of that expansion. Hartnett also calculated that the initial universe was about eight million light-years in radius before the expansion, and is 13.5 billion light-years in radius today. The expansion itself produced tremendous time dilation in the terrestrial frame of reference, so that the light from even the most distant objects in the universe could still have reached the earth for [[Adam]] to see.
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[[Image:56200main dark expansion-lg.jpg|300px|right]]'''Dark energy''' is one of two concepts (the other is [[dark matter]]) that [[Big Bang]] [[cosmology|cosmologists]] and [[astrophysicists]] have invented to explain the most serious differences to date between [[astronomy|astronomical]] observations of an [[expanding universe]] and their own expectations. It is "the most popular way to explain recent observations that the universe appears to be expanding at an accelerating rate";<ref>[http://www.encyclopediaproject.net/wiki/Dark_energy New World Encyclopedia]</ref> Astronomers and cosmologists have been speculating on the nature of this dark energy for ten years.
[[Image:56200main dark expansion-lg.jpg|300px|right]]'''Dark energy''' is one of two concepts (the other is [[dark matter]]) that [[Big Bang]] [[cosmology|cosmologists]] and [[astrophysicists]] have invented to explain the most serious differences to date between [[astronomy|astronomical]] observations of an [[expanding universe]] and their own expectations. It is "the most popular way to explain recent observations that the universe appears to be expanding at an accelerating rate";<ref>[http://www.encyclopediaproject.net/wiki/Dark_energy New World Encyclopedia]</ref> Astronomers and cosmologists have been speculating on the nature of this dark energy for ten years.
== Introduction of the concept ==
== The problem ==
In 1998, the Supernova Cosmology Project observed 42 Type Ia supernovae, most of these from the ground, in an effort to measure the rate of deceleration of the expansion of the [[universe]].<ref name=scp>Perlmutter S., Aldering G., Goldhaber G., ''et al.'' "Measurements of Omega and Lambda from 42 High-Redshift Supernovae." ''Astrophys. J.'' 517 (1999) 565-586. {{arXiv|astro-ph/9812133v1}} Accessed July 26, 2008</ref> (Type Ia supernovae are objects of nearly uniform brightness and thus are favorite objects for standardization of [[redshift]] and hence of the speed of expansion.) These supernovae were actually much dimmer than expected, a finding that indicated an ''acceleration'' of expansion, not the deceleration that gravitational attraction would produce. A competing group, the High-Z Supernova Search Team, reported similar results from their observations of 14 other supernovae.<ref name=hiz>Reiss AG, Filippenko AV, Challis P, ''et al.'' "Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant." ''Astron. J.'' 116 (1998) 1009-1038. {{arXiv|astro-ph/9805201v1}} Accessed July 26, 2008</ref> (The symbol ''z'' stands for [[redshift]] in this context.) The findings of an accelerated universe came as a profound surprise to all interested observers and commentators.<ref name=Newman>Newman P, and Tyler P, eds. "[http://universe.nasa.gov/science/darkenergy.html Beyond Einstein: What is the Mysterious Dark Energy Pulling the Universe Apart]?" [[NASA]], n.d. Accessed July 26, 2008.</ref>
In 1998, the Supernova Cosmology Project observed 42 Type Ia supernovae, most of these from the ground, in an effort to measure the rate of deceleration of the expansion of the [[universe]].<ref name=scp>Perlmutter S., Aldering G., Goldhaber G., ''et al.'' "Measurements of Omega and Lambda from 42 High-Redshift Supernovae." ''Astrophys. J.'' 517 (1999) 565-586. {{arXiv|astro-ph/9812133v1}} Accessed July 26, 2008</ref> (Type Ia supernovae are objects of easily discernible brightness and thus are favorite objects for standardization of [[redshift]] and hence of the speed of expansion.) These supernovae were actually much dimmer than expected, a finding that indicated an ''acceleration'' of expansion, not the deceleration that gravitational attraction would produce. A competing group, the High-Z Supernova Search Team, reported similar results from their observations of 14 other supernovae.<ref name=hiz>Reiss AG, Filippenko AV, Challis P, ''et al.'' "Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant." ''Astron. J.'' 116 (1998) 1009-1038. {{arXiv|astro-ph/9805201v1}} Accessed July 26, 2008</ref> (The symbol ''z'' stands for [[redshift]] in this context.) The findings of an accelerated universe came as a profound surprise to all interested observers and commentators.<ref name=Newman>Newman P, and Tyler P, eds. "[http://universe.nasa.gov/science/darkenergy.html Beyond Einstein: What is the Mysterious Dark Energy Pulling the Universe Apart]?" [[NASA]], n.d. Accessed July 26, 2008.</ref> More recent surveys have shown that the discrepancy persists.<ref name=Reiss>Reiss AG, ''et al.'', "Type Ia supernovae discoveries at z > 1 from the Hubble Space Telescope: Evidence for Past Deceleration and Constraints on Dark Energy Evolution", ''Ap. J.'' '''607''':665-687, 2004</ref><ref name=Astier>Astier P, ''et al.'', "The Supernova Legacy Survey: Measurement of Ω<sub>m</sub>, Ω<sub>Λ</sub>, and w from the First Year Data Set," ''A&A'' '''447''':31-48, 2006</ref>
Saul Perlmutter, Michael Turner, and Martin White appear to have coined the term '''dark energy''' to name the phenomenon that is causing the apparent acceleration.<ref name=neolog>Perlmutter S, Turner MS, and White M. "Constraining dark energy with SNe Ia and large-scale structure." ''Phys. Rev. Lett.'' 83 (1999) 670-673. {{arXiv|astro-ph/9901052v2}} Accessed July 26, 2008.</ref> The term appears again in the more comprehensive paper of Bahcall, Ostriker, Perlmutter, and Steinhardt, that proposes that a heretofore unsuspected form of energy "overcomes the gravitational self-attraction of matter and causes the expansion [of the universe] to speed up."<ref name=triangle>Bahcall NA, Ostriker JP, Perlmutter S, and Steinhardt PJ. "The Cosmic Triangle: Revealing the State of the Universe." ''Science'' 28 May 1999: Vol. 284. no. 5419, pp. 1481-1488. {{doi|10.1126/science.284.5419.1481}} Accessed July 26, 2008</ref><ref name=Preuss>Preuss P. "[http://www.lbl.gov/Science-Articles/Archive/dark-energy.html Dark Energy Fills the Cosmos]." ''ScienceBeat'', Lawrence Berkeley Laboratory, June 1, 1999. Accessed July 26, 2008.</ref>
==Young Earth Creation Science solution==
[[John Hartnett]], in ''[[Starlight, Time and the New Physics]],''<ref name=Hartnett>Hartnett, John. ''[[Starlight, Time and the New Physics]]''. Creation Book Publishers, 2007. ISBN 9780949906687.</ref> reminds his readers that Moshe Carmeli first formed a new model, called [[cosmological relativity]], and through this model predicted that the universe would in fact appear to be accelerating. He made this prediction in 1996, ''two years before'' the publication of the Type Ia supernova data and the introduction of the idea of "dark energy" into cosmological discussions. In making this prediction, Carmeli ''did not'' invoke either dark energy or dark matter.
Hartnett extended Carmeli's model and discarded several assumptions that Carmeli initially had thought were safe. This included the assumption that the matter density of the universe is at the critical level for a "coasting" universe.
The full derivation of Hartnett's field equation that describes the motion of far-off objects is included in Appendix 2 of his book. Briefly, Hartnett begins with Moshe Carmeli's [[Cosmological Relativity]], which adds a dimension of the radial velocity of a far-off object to the Einsteinian dimensions of space and time. This radial velocity is related to the distance of the object by this equation:
<math>v = \bigg( \frac{1}{\tau} \bigg) r</math>
where <math>\tau</math> is a constant (evaluated at 4.28 * 10<sup>17</sup> s) that is the reciprocal of the Hubble factor ''H''<sub>0</sub> in weak gravity.<ref>Evolutionistic astronomers might assume that this value gives the age of the universe; it does in fact give a value very close to the visible radius of the universe, measured in light-years. It probably does represent a value that an observer at the limits of the visible universe might measure for its age—because the Carmeli-Hartnett system ''also'' predicts tremendous time dilation at the center of the expansion.</ref>
Adding this dimension requires adding a new term to the classic space-time interval, and so:
<math>ds^2 = \Bigg( 1 + \frac{\Phi}{c^2}\Bigg)c^2dt^2 - dr^2 + \Bigg(1 + \frac{\Psi}{\tau^2}\Bigg) \tau dv^2</math>
where r is the distance of the object from [[earth]] (or more properly, our [[galaxy]]).
An observation of a far-off object is typically made at a given moment and from a given place, and so ds=dt=0. So the above equation simplifies to:
<math> - dr^2 + \Bigg(1 + \frac{\Psi}{\tau^2}\Bigg) \tau dv^2 = 0</math>
Carmeli's solution is:
<math>\frac{dr}{dv} = \tau \sqrt{1 + (1 - \Omega ) \frac{r^2}{c^2\tau^2}}</math>
where <math>\Omega</math> is the mass-energy density fraction of the universe. Specifically, <math>\Omega = \rho/\rho_c</math>, where <math>\rho_c</math> is the ''critical'' mass density, above which the universe would be closed and destined to collapse.
The integral of the above equation, expressed in dimensionless numbers, is:
<math>\frac{r}{c\tau} = \frac{\sinh(\beta \sqrt{1-\Omega})}{\sqrt{1-\Omega}}</math>
where <math>\beta</math> = <math>v/c</math> is the radial velocity of the object, as a fraction of the [[speed of light]]. This fraction is itself a function of the [[redshift]] of the object (symbol: z):
<math>\beta = \frac{(1+z)^2 + 1}{(1+z)^2 - 1}</math>
The key fact is that the matter density anywhere in the universe is ''also'' a function of redshift. In the simple case of "flat" space,
<math>\Omega = \Omega_m(1+z)^3</math>
where <math>\Omega_m</math> is the weighted-average mass-energy density of the universe in the present [[epoch]].
Hartnett tested these equations against the High-Z Supernova Search Team data. To do this, he used these equations to convert <math>r/c\tau</math> to an absolute magnitude:
<math>m(z) = M + 5 \log D_L (z;\Omega)</math>
Here,
<math>D_L (z;\Omega) = \frac{(1+z)}{\sqrt{1-\beta^2}}\frac{r}{c\tau}</math>
is an independent luminosity distance, and
<math>M = 5 \log \bigg(\frac{c\tau}{Mpc}\bigg) + 25 + M_B + a</math>
where <math>M_B</math> is the highest absolute magnitude of any given supernova and <math>c\tau</math> is expressed in mega[[parsec]]s.
Recall that <math>\beta</math> is a function of z, and r is sensitive to the mass-energy density fraction.
Hartnett plotted the difference <math>M-M_B</math> against redshift for the supernovas studied most recently by Riess and Astier<ref name=Riess/><ref name=Astier/>. He then adjusted the parameters <math>a</math> and <math>\Omega_m</math> to achieve the best statistical fit to the observations. He obtained these values:
<math>a = 0.2284</math>
and
<math>\Omega_m = 0.0401
The second value is consistent with a mass-energy density that is four percent of critical. This is about twice as much matter as Fu<!--k-->ugita ''et al.'' have determined that the universe has within it, but also at the upper limit of the range of that value.<ref name=Fu<!--k-->ugita>Fu<!--k-->ugita M, Hogan CJ, and Peebles PJE, "The cosmic baryon budget", ''Ap. J.'' '''503''':518-530, 1998</ref> It is also the same as the fraction of mass-energy in the universe that most evolutionists now believe to be composed of ordinary or baryonic matter (see below).
Hartnett's model thus predicts as much mass-energy as other astronomers have already estimated that the universe has, and no more, within the limits of that estimate.
== Evolutionist/uniformitarian view ==
=== The dark energy concept ===
Reiss, Astier, and their respective teams did not use this model. Instead, they relied upon the Friedmann-Lemaître cosmological model. That model predicted far more mass-energy than the universe possesses, beyond any rational estimate.
Saul Perlmutter, Michael Turner, and Martin White appear to have coined the term '''dark energy''' to name the phenomenon that is causing the apparent acceleration that they found.<ref name=neolog>Perlmutter S, Turner MS, and White M. "Constraining dark energy with SNe Ia and large-scale structure." ''Phys. Rev. Lett.'' 83 (1999) 670-673. {{arXiv|astro-ph/9901052v2}} Accessed July 26, 2008.</ref> The term appears again in the more comprehensive paper of Bahcall, Ostriker, Perlmutter, and Steinhardt, that proposes that a heretofore unsuspected form of energy "overcomes the gravitational self-attraction of matter and causes the expansion [of the universe] to speed up."<ref name=triangle>Bahcall NA, Ostriker JP, Perlmutter S, and Steinhardt PJ. "The Cosmic Triangle: Revealing the State of the Universe." ''Science'' 28 May 1999: Vol. 284. no. 5419, pp. 1481-1488. {{doi|10.1126/science.284.5419.1481}} Accessed July 26, 2008</ref><ref name=Preuss>Preuss P. "[http://www.lbl.gov/Science-Articles/Archive/dark-energy.html Dark Energy Fills the Cosmos]." ''ScienceBeat'', Lawrence Berkeley Laboratory, June 1, 1999. Accessed July 26, 2008.</ref>
In 2001, Reiss and his colleagues used the [[Hubble Space Telescope]] to capture on film the furthest supernova then seen, SN1997ff, at a distance of 10 billion light-years. The magnitude and redshift of this object were consistent with a decelerating expansion. This is consistent with the model that Reiss and others were forming at the time, stating that the expansion of the universe was initially decelerating and later accelerated after its matter density dropped below a critical level.<ref name=Lloyd>Lloyd, Robin. "[http://ww.space.com/scienceastronomy/astronomy/farthest_supernova_010402.html Farthest Supernova Detected, 'Dark Energy' Suspected]." ''<http://ww.space.com/>'' April 2, 2001. Accessed July 26, 2008.</ref>
In 2001, Reiss and his colleagues used the [[Hubble Space Telescope]] to capture on film the furthest supernova then seen, SN1997ff, at a distance of 10 billion light-years. The magnitude and redshift of this object were consistent with a decelerating expansion. This is consistent with the model that Reiss and others were forming at the time, stating that the expansion of the universe was initially decelerating and later accelerated after its matter density dropped below a critical level.<ref name=Lloyd>Lloyd, Robin. "[http://ww.space.com/scienceastronomy/astronomy/farthest_supernova_010402.html Farthest Supernova Detected, 'Dark Energy' Suspected]." ''<http://ww.space.com/>'' April 2, 2001. Accessed July 26, 2008.</ref>
In 2003, a survey of 11 Type Ia supernovae by the HST confirmed the earlier findings of an accelerated expansion of the universe. Astronomers consider this the most definitive evidence to date for the existence of dark energy.<ref name=HubbleConf>Knop RA, Aldering G, Amanullah R, ''et al.'' "New Constraints on $\Omega_M$, $\Omega_\Lambda$, and w from an Independent Set of Eleven High-Redshift Supernovae Observed with HST" ''Astrophys. J.'' 598 (2003) 102 {{arXiv|astro-ph/0309368v1}} Accessed July 26, 2008</ref>
In 2003, a survey of 11 Type Ia supernovae by the HST confirmed the earlier findings of an accelerated expansion of the universe. Astronomers consider this the most definitive evidence to date for the existence of dark energy.<ref name=HubbleConf>Knop RA, Aldering G, Amanullah R, ''et al.'' "New Constraints on $\Omega_M$, $\Omega_\Lambda$, and w from an Independent Set of Eleven High-Redshift Supernovae Observed with HST" ''Astrophys. J.'' 598 (2003) 102 {{arXiv|astro-ph/0309368v1}} Accessed July 26, 2008</ref>
== Nature of dark energy ==
=== Nature of dark energy ===
[[Image:DarkMatterNASA1.jpg|300px|right]]Dark energy today is inferred, not detected. The calculated quantity of dark energy is the apparent excess of [[energy]] that somehow abruptly accelerated the expansion of the [[universe]]. Current estimates of the time that has passed since this acceleration occurred vary from 5<ref name=Chaikin>Chaikin, Andrew. "[http://www.space.com/scienceastronomy/astronomy/cosmic_darknrg_020115-1.html Dark Energy: Astronomers Still 'Clueless' About Mystery Force Pushing Galaxies Apart ]." ''Space.com'', January 15, 2002. Accessed July 26, 2008.</ref> to 7.5 billion years.<ref name=Williams>Williams G. "[http://nasascience.nasa.gov/astrophysics/what-is-dark-energy Dark Energy, Dark Matter]." Science Mission Directorate, [[NASA]], May 15, 2008. Accessed July 26, 2008.</ref><ref name=nasa1>Authors unknown. "[http://www.nasa.gov/missions/deepspace/f_dark-energy.html Dark energy changes the universe]." [[NASA]], February 27, 2004. Accessed July 25, 2008.</ref>
[[Image:DarkMatterNASA1.jpg|300px|right]]Dark energy today is inferred, not detected. The calculated quantity of dark energy is the apparent excess of [[energy]] that somehow abruptly accelerated the expansion of the [[universe]]. Current estimates of the time that has passed since this acceleration occurred vary from 5<ref name=Chaikin>Chaikin, Andrew. "[http://www.space.com/scienceastronomy/astronomy/cosmic_darknrg_020115-1.html Dark Energy: Astronomers Still 'Clueless' About Mystery Force Pushing Galaxies Apart ]." ''Space.com'', January 15, 2002. Accessed July 26, 2008.</ref> to 7.5 billion years.<ref name=Williams>Williams G. "[http://nasascience.nasa.gov/astrophysics/what-is-dark-energy Dark Energy, Dark Matter]." Science Mission Directorate, [[NASA]], May 15, 2008. Accessed July 26, 2008.</ref><ref name=nasa1>Authors unknown. "[http://www.nasa.gov/missions/deepspace/f_dark-energy.html Dark energy changes the universe]." [[NASA]], February 27, 2004. Accessed July 25, 2008.</ref>
[[Naturalism|naturalistic]] cosmologists estimate that 70 percent of the total energy in the universe consists of dark energy.<ref name=Williams/> [[Dark matter]] occupies another 25 percent. The remaining portion is the familiar, or baryonic matter of which all objects are made.<ref name=nasa1/>
[[Uniformitarianism|Uniformitarian]] cosmologists have three theories of what form this energy might take:
[[Uniformitarianism|Uniformitarian]] cosmologists have three theories of what form this energy might take:
David Cline wrote in ''[[Scientific American]]'' in 2003 the following: "We know little about that sea. The terms we use to describe its components, [[dark matter]] and dark energy, serve mainly as expressions of our ignorance.”<ref>http://www.creationscience.com/onlinebook/ReferencesandNotes54.html#wp1458731</ref> Similarly, David Shiga authored an article in 2007 published by ''[[New Scientist]]'' titled "Is Dark Energy and Illusion?".<ref>http://space.newscientist.com/article/dn11498-is-dark-energy-an-illusion.html</ref>
David Cline wrote in ''[[Scientific American]]'' in 2003 the following: "We know little about that sea. The terms we use to describe its components, [[dark matter]] and dark energy, serve mainly as expressions of our ignorance.”<ref>http://www.creationscience.com/onlinebook/ReferencesandNotes54.html#wp1458731</ref> Similarly, David Shiga authored an article in 2007 published by ''[[New Scientist]]'' titled "Is Dark Energy and Illusion?".<ref>http://space.newscientist.com/article/dn11498-is-dark-energy-an-illusion.html</ref>
== Implications of dark energy ==
=== Implications of dark energy ===
[[Image:56197main dark schematic-lg.jpg|thumb|300px|left|Three suggested fates of the universe]]Conventional cosmologists have thus far realized only that their understanding of cosmology is incomplete. They now know that the universe is expanding, that this expansion is accelerating, and that their existing models cannot account for this acceleration or begin to suggest a cause. They believe also that dark energy can explain the current temperature of the Cosmic Microwave Background radiation.<ref name=Chaikin/><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> But they are no closer to defining the nature of dark energy than they were when Perlmutter ''et al.'' first coined the term.
[[Image:56197main dark schematic-lg.jpg|thumb|300px|left|Three suggested fates of the universe]]Evolutionistic cosmologists have thus far realized only that their understanding of cosmology is incomplete. They now know that the universe is expanding, that this expansion is accelerating, and that their existing models cannot account for this acceleration or begin to suggest a cause. They believe also that dark energy can explain the current temperature of the Cosmic Microwave Background radiation.<ref name=Chaikin/><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> But they are no closer to defining the nature of dark energy than they were when Perlmutter ''et al.'' first coined the term.
This has not stopped them from speculating on what might happen to the universe in the future. They currently recognize three possibilities:<ref name=nasa1/>
This has not stopped them from speculating on what might happen to the universe in the future. They currently recognize three possibilities:<ref name=nasa1/>
Other scientists raise the question of whether the proportion of dark energy in the universe is a fundamental quantity of space. If it is not, they say, then this universe is only one of many.<ref name=Britt>Britt RR. "[http://www.space.com/scienceastronomy/mystery_monday_040531.html Dark Energy Tied to Human Origins]." ''Space.com'', May 31, 2004. Accessed July 26, 2008.</ref>
Other scientists raise the question of whether the proportion of dark energy in the universe is a fundamental quantity of space. If it is not, they say, then this universe is only one of many.<ref name=Britt>Britt RR. "[http://www.space.com/scienceastronomy/mystery_monday_040531.html Dark Energy Tied to Human Origins]." ''Space.com'', May 31, 2004. Accessed July 26, 2008.</ref>
== A Competing Secular Explanation ==
== Criticisms of the dark energy concept ==
===Creationist criticism===
Dr. [[Walt Brown]] wrote the following about the concept of dark energy:
{{cquote|Neither “dark matter” (created to hold the [[universe]] together) nor “dark energy” (created to push the universe apart) has been seen or measured. We are told that “most of the universe is composed of invisible dark matter and dark energy.” Few realize that both mystical concepts were devised to preserve the [[big Bang theory|big bang theory]].<ref>http://www.creationscience.com/onlinebook/AstroPhysicalSciences16.html</ref>}}
Dark energy is a mathematical convenience. Some authorities admit that it may never be detectable. One reason why no one would ever detect it is that it represents an error. [[Evolution]]istic cosmologists have admitted that dark energy might represent an error of their understanding of gravity. Creationists suggest that the error is far more fundamental.
=== A Competing Secular Explanation ===
Timothy Clifton, at Oxford University, said in an interview published at Space.com on October 1, 2008 that the solar system might be enclosed in a volume of space having a disproportionate lack of matter. According to his "void model," light from far-distant objects appears dim, not because the objects are retreating from the earth or even because the cosmos is expanding, but because the void condition does not focus the light as a matter-filled cosmos normally would. Clifton expresses one misgiving about his model that clearly reveals his worldview, however: it would negate the so-called Copernican Principle and require astronomers and cosmologists to regard the earth as a special place.<ref name=Clifton>Moskowitz, Clara. "[http://www.foxnews.com/story/0,2933,430943,00.html Scientists: Earth May Exist in Giant Cosmic Bubble]. Space.com, October 1, 2008. Hosted on <http://www.foxnews.com/>. Accessed October 1, 2008.</ref>
Timothy Clifton, at Oxford University, said in an interview published at Space.com on October 1, 2008 that the solar system might be enclosed in a volume of space having a disproportionate lack of matter. According to his "void model," light from far-distant objects appears dim, not because the objects are retreating from the earth or even because the cosmos is expanding, but because the void condition does not focus the light as a matter-filled cosmos normally would. Clifton expresses one misgiving about his model that clearly reveals his worldview, however: it would negate the so-called Copernican Principle and require astronomers and cosmologists to regard the earth as a special place.<ref name=Clifton>Moskowitz, Clara. "[http://www.foxnews.com/story/0,2933,430943,00.html Scientists: Earth May Exist in Giant Cosmic Bubble]. Space.com, October 1, 2008. Hosted on <http://www.foxnews.com/>. Accessed October 1, 2008.</ref>
NASA and the [[United States]] Department of Energy have also proposed a Joint Dark Energy Mission, essentially a new, very-high-resolution space telescope. Three different telescope designs are now under study.<ref name=jdem>Newman P and Tyler P. "[http://universe.nasa.gov/program/probes/jdem.html Beyond Einstein: The Joint Dark Energy Mission]." [[NASA]], n.d. Accessed July 26, 2008.</ref> Timothy Clifton, the proponent of the "void model" mentioned above, hopes that observations by JDEM might provide a reliable test of his model.<ref name=Clifton/>
NASA and the [[United States]] Department of Energy have also proposed a Joint Dark Energy Mission, essentially a new, very-high-resolution space telescope. Three different telescope designs are now under study.<ref name=jdem>Newman P and Tyler P. "[http://universe.nasa.gov/program/probes/jdem.html Beyond Einstein: The Joint Dark Energy Mission]." [[NASA]], n.d. Accessed July 26, 2008.</ref> Timothy Clifton, the proponent of the "void model" mentioned above, hopes that observations by JDEM might provide a reliable test of his model.<ref name=Clifton/>
==External Links==
==External Links==