Planet

From CreationWiki, the encyclopedia of creation science

The word planet comes from the Greek word πλανήτης (planetes) which is derived from the word πλάνης (planes) meaning "wanderer."^[1]

Originally the term was applied to any object that moved in the sky including stars. However, as a more complete picture of our universe emerged from the work of astronomers, the classification of a planet became more specific. In our solar system there are eight definite planets; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. In 2006 the International Astronomical Union (IAU) demoted Pluto from its classification as a planet to dwarf planet because it did not conform to recently established criteria.

Contents 1 History 1.1 Geocentric Model 1.2 Heliocentric Model 2 Table of Planets 3 Extrasolar Planets 4 Planet Re-defined 5 References 6 Related Links 7 See Also

History

Geocentric Model

Main Article: Geocentricity

Geocentrism is the belief that the Earth is located at the center of the universe. Biblical creationists generally view the creation of the cosmos as an Earth-centered event, and the space beyond our world created simply to "declare the glory of God" (Psalm 19:1 ). Therefore, it is largely assumed the Earth is at the relative center of the cosmos.^{[Reference needed]}

While very few creationist hold to a strict geocentric view, galactocentricity has received acceptance by many. Evidence, such as quantized redshift, has been offered as strong support that the Milky Way exists at the center of the universe.

Heliocentric Model

Main Article: Heliocentricity

Heliocentricity is a reference system where the sun is at the center. Our planetary system is heliocentric wherein the ten known planets are orbiting the sun, and is therefore known as a "solar system".

Early astronomers such as Nicolas Copernicus, Galileo Galilei, and Johannes Kepler helped revolutionize the previously held view of geocentrism, which was supported by Aristotle's cosmology, and placed the Earth at the center. The Copernican theory proported that the sun was the center of the universe and the planets rotated around the sun each year. He also asserted that Earth had motion around its center, and a simple explanation for the retrograde motions of the planets.

Table of Planets

List of all the planets, from the innermost to the outermost:

Name	Perihelion	Aphelion	Eccentricity	Sidereal year	Inclination	Mass	Sidereal day
Mercury (planet)	460000000000.307 AU46,000,000 km 28,583,074.843 mi	700000000000.468 AU70,000,000 km 43,495,983.457 mi	0.205630690.206	87.969340.241 a87.969 da	0.122258045174187.005 °0.122 rad 7.783 grad	3.3E+230.0552 M⊕3.3e+23 kg 1.73803e-4 M♃	5067031.681,407.509 h58.646 da
Venus	1074762590000.718 AU107,476,259 km 66,782,651.192 mi	1089421090000.728 AU108,942,109 km 67,693,488.154 mi	0.00680.0068	224.700690.615 a224.701 da	0.0592488666503773.395 °0.0592 rad 3.772 grad	4.8685E+240.815 M⊕4.8685e+24 kg 0.00256 M♃	-20996815.68-5,832.449 h-243.019 da
Earth	1470900000000.983 AU147,090,000 km 91,397,488.666 mi	1521000000001.017 AU152,100,000 km 94,510,558.339 mi	0.016710220.0167	365.2563661 a365.256 da	8.7266462599717E-075.0e-5 °8.72665e-7 rad 5.55556e-5 grad	5.9736E+241 M⊕5.9736e+24 kg 0.00315 M♃	86164.223.935 h0.997 da
Mars	2066445450001.381 AU206,644,545 km 128,402,967.296 mi	2492287300001.666 AU249,228,730 km 154,863,553.1 mi	0.0930.093	686.961.881 a686.96 da	0.0323060444544151.851 °0.0323 rad 2.057 grad	6.4185E+230.107 M⊕6.4185e+23 kg 3.38047e-4 M♃	88642.66298424.623 h1.026 da
Jupiter	7405200000004.95 AU740,520,000 km 460,137,795.276 mi	8166200000005.459 AU816,620,000 km 507,424,143.005 mi	0.048390.0484	4330.58662511.857 a4,330.587 da	0.0227765467385261.305 °0.0228 rad 1.45 grad	1.8987E+27317.721 M⊕1.8987e+27 kg 1 M♃	357309.925 h0.414 da
Saturn	13493727874009.02 AU1.34937e+9 km 838,461,377.679 mi	150345859350010.05 AU1.50346e+9 km 934,205,858.723 mi	0.0540.054	10759.534529.458 a10,759.534 da	0.0433539786195392.484 °0.0434 rad 2.76 grad	5.6846E+2695.124 M⊕5.6846e+26 kg 0.299 M♃	38818.810.783 h0.449 da
Uranus	274130000000018.324 AU2.7413e+9 km 1.70336e+9 mi	300362000000020.078 AU3.00362e+9 km 1.86636e+9 mi	0.04570.0457	30681.6153001584.002 a30,681.615 da	0.0129852496348380.744 °0.013 rad 0.827 grad	8.6832E+2514.53 M⊕8.6832e+25 kg 0.0457 M♃	-62064-17.24 h-0.718 da
Neptune	444445000000029.709 AU4.44445e+9 km 2.76165e+9 mi	454567000000030.386 AU4.54567e+9 km 2.82455e+9 mi	0.01130.0113	60189.5475164.79 a60,189.548 da	0.030874874467781.769 °0.0309 rad 1.966 grad	1.0243E+2617.14 M⊕1.0243e+26 kg 0.0539 M♃	5799616.11 h0.671 da

Extrasolar Planets

An extrasolar planet or exoplanet is any planet outside our solar system. Speculation on the existence of exoplanets probably dates to September of 1916, with the first article describing the unusually large proper motion of Barnard's Star, a red dwarf star about 1.82 parsecs distant from Earth.^[3] As of March 23, 2008, 277 exoplanets in orbit around 238 stars are now known.^[4] Most such planets are gas giants, but speculation about the finding of an Earth-like exoplanet continues. The lightest-mass exoplanet found thus far is a 7.5-Earth-mass planet in orbit around the star Gliese 876.^[5]

Some evolutionists assert that planetary and galaxy formation take millions of years. However, in 2004, the Spitzer Space Telescope detected a clearing of dust around a star that is "only" a million years old. They theorize that the object that cleared the dust is an exoplanet at least as large as Jupiter. This would be (by evolutionary standards) the youngest planet ever observed. According to Alan Boss, an astronomer for the Carnegie Institution of Washington, the find "has profound implications for the prevalence of planetary systems similar to our own. That means you can make gas giant planets - a major component of our own solar system - in a short time scale, in even the shortest-lived disc." The discovery suggested scientists would have to rethink their models about planetary formation.^[6]

Planet Re-defined

On August 24, 2006, the International Astronomical Union (IAU) formally downgraded Pluto from an official planet of our solar system to a mere dwarf planet. There are now eight official planets of our solar system and according to The Final IAU Resolution on the definition of "planet" ready for voting statement on the IAU website,

“

RESOLUTION 5A The IAU therefore resolves that planets and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way: (1) A "planet"1 is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. (2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape2, (c) has not cleared the neighbourhood around its orbit, and (d)is not a satellite. (3) All other objects3, except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies". 1The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. 2An IAU process will be established to assign borderline objects into either dwarf planet and other categories. 3These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies. [7]

”

While parameters (b) and (c) appeal to assumptions of unobservable processes in planetary origin, the overall assumption is the naturalistic philosophy of the formation of the solar system. From a creationist perspective the planets were made mature and with planetary laws to govern them on day four of creation.

Historically there may have been difficulty in defining what exactly constitutes a planet, there appears to be several characteristics traditional planets share:

• In orbit around the sun.
• Basically spherical.
• Dominant of their orbit, having no other significant objects in their path around the sun.

References

1. ↑ "Entry for 'planet'," Wiktionary, January 9, 2008. Accessed January 14, 2008.
2. ↑ God and Cosmos by John Byl. p17-18
3. ↑ Bell, George H. "The Search for the Extrasolar Planets: A Brief History of the Search, the Findings and the Future Implications." Arizona State University, April 5, 2001. Accessed March 23, 2008.
4. ↑ Jackson, Randall, curator. "PlanetQuest: Exoplanet Exploration." JPL, NASA. Accessed March 23, 2008.
5. ↑ <http://exoplanets.org/> Center for Integrative Planetary Science, University of California, Berkeley, California. Accessed March 23, 2008.
6. ↑ Mullen, Leslie. "Young Planet Challenges Old Theories." Astrobiology Magazine online, May 28, 2004. Accessed March 7, 2008.
7. ↑ "IAU0602: the Final IAU Resolution on the Definition of 'Planet' Ready for Voting," International Astronomical Union, 2005. Accessed January 14, 2008.

Related Links

• IAU International Astronomical Union homepage
• Planet by Wikipedia

Browse

See Also

• Young solar system evidence
• Galaxy
• Nebula Hypothesis
• Terrestrial planet
• Gas giant

	The Solar System
Star	Sol
Planets	Vulcan • Mercury • Venus • Earth • Mars • Jupiter • Saturn • Uranus • Neptune
Dwarf Planets	Ceres • Pluto • Eris
Asteroid Belt	Major asteroids • C-type asteroids • S-type asteroids • M-type asteroids
Trans-Neptunian Objects	Kuiper belt • Scatter disk • Oort cloud • Nemesis
Moons	Terrestrial • Martian • Jovian • Saturnine • Uranian • Neptunian • Plutonian • Eridian
Featured moons	Moon • Phobos • Deimos • Io • Europa • Ganymede • Callisto • Mimas • Enceladus • Tethys • Dione • Rhea • Titan • Hyperion • Iapetus • Miranda • Ariel • Umbriel • Titania • Oberon • Triton • Nereid • Charon • Nix • Hydra • Dysnomia