Difference between revisions of "Planet"

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{{Solarsystem}}
 
{{Solarsystem}}
A '''planet''' is a astronomical body that is in [[orbit]] around a [[star]], has sufficient mass for its own [[gravity]] to overcome rigid body forces so that it assumes an approximately spherical shape, and has cleared the neighborhood around its orbit <ref>http://www.iau.org/iau0603.414.0.html</ref>.
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A '''planet''' is a astronomical body that is in [[orbit]] around a [[star]], has sufficient mass for its own [[gravity]] to overcome rigid body forces, assumes an approximately spherical shape, and has cleared the neighborhood around its orbit <ref>http://www.iau.org/iau0603.414.0.html</ref>, i.e. has "swept out" the area around its orbit during its formation, accreting into its mass all other smaller bodies within its orbit. Consequently, a planet dooes not share its orbital region with any other bodies of significant size, except for its satellites or those collected later by virtue of its gravitational field.  
 
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The phrase "cleared the neighborhood around its orbit" refers to a body "sweeping out" the area around its orbit as it forms, by causing all other smaller bodies in its orbit to accrete with it. As a consequence it does not then share its orbital region with any other bodies of significant size, except for satellites or those collected later under its gravitational influence.  
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== Young Earth Creationism View ==
 
== Young Earth Creationism View ==

Revision as of 18:21, May 28, 2007

A planet is a astronomical body that is in orbit around a star, has sufficient mass for its own gravity to overcome rigid body forces, assumes an approximately spherical shape, and has cleared the neighborhood around its orbit [1], i.e. has "swept out" the area around its orbit during its formation, accreting into its mass all other smaller bodies within its orbit. Consequently, a planet dooes not share its orbital region with any other bodies of significant size, except for its satellites or those collected later by virtue of its gravitational field.

Young Earth Creationism View

Young earth creationist assert that materialistic explanations of the planet formation are inadequate and contra-evidential. [2][3] In addition, creationists often cite the secular scientific literature in order to make the case that materialist explanations of planet formation are inadequate:


“... most every prediction by theorists about planetary formation has been wrong.” Scott Tremaine, as quoted by Richard A. Kerr who was proposing a new planetary formation model, “Jupiters Like Our Own Await Planet Hunters,” [4]


"No one knows quite how planetesimals ever attain protoplanet status." [5]


“It turns out to be surprisingly difficult for planetesimals to accrete mass during even the most gentle collisions.” Erik Asphaug, “The Small Planets,” [6]

References

  1. http://www.iau.org/iau0603.414.0.html
  2. http://www.creationscience.com/onlinebook/AstroPhysicalSciences3.html
  3. http://www.answersingenesis.org/home/area/faq/astronomy.asp
  4. Science, Vol. 295, 25 January 2002, p. 605 cited at: http://www.creationscience.com/onlinebook/ReferencesandNotes43.html
  5. D. Kaisler, The puzzles of planethood, Sky & Telescope 104(2):32-38, 2002.
  6. Scientific American, Vol. 282, May 2000, p. 54. cited at: http://www.creationscience.com/onlinebook/ReferencesandNotes46.html