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Created the page, continuing to create the pages in the nebulae template
A '''planetary nebula''' is a rare type of [[nebula]] that is smaller and fainter than other types of nebulae such as [[diffuse nebulae]].<ref name=seds>[http://www.messier.seds.org/planetar.html Planetary nebulae] from messier.seds.org</ref> They are typically composed of a [[white dwarf]] surrounded by shells of expanding luminous gas.<ref name=britannica>[https://www.britannica.com/topic/planetary-nebula Planetary nebulae] from britannica.com</ref> There are thought to be 20,000 such objects in the [[Milky Way]], though the effects of [[dust]] mean only around 1,800 have been observed.<ref name=britannica/> A superb example of a planetary nebula is the [[Ring nebula]].
==History==
The first observation of a planetary nebula was by [[Charles Messier]].<ref name=seds/> In 1764, Messier observed the [[Dumbbell nebula]]. Five years later, Messier observed the [[Ring nebula]]. His colleague, Pierre Méchain, discovered two more in 1780 and 1781, [[Little dumbbell nebula]] and the [[Owl nebula]]. These are the four planetary nebulae in the [[Messier catalogue]].
The term "planetary nebula" was coined by [[William Herschel]] in 1784/1785 as he believed them appear like the [[planet]] [[Uranus]] which he had recently discovered.<ref name=seds/> Hershel went on to discover a further 33 planetary nebulae through his systematic observation of the night sky.
==Properties==
Planetary nebulae are normally much smaller than other nebulae, having radii of order 1 [[light year]] and a mass of 0.3 solar masses.<ref name=britannica/> Most contain a [[star]] which ionizes the surrounding gas creating spectacular colours. The nebulae tend contain large quantities of [[element]]s heavier than [[helium]] such as [[carbon]] and [[oxygen]]. These different elements are responsible for the wide variety of colours in planetary nebulae. The abundance of each element varies from one nebula to another. Some nebulae also contain dust.
For most planetary nebulae, the star at the centre is a [[white dwarf]].<ref name=britannica/> These are small stars but extremely dense, having densities of over a billion kg/m<sup>3</sup>.<ref>[https://imagine.gsfc.nasa.gov/science/objects/dwarfs2.html White dwarfs] from imagine.gsfc.nasa.gov</ref> They are also extremely hot, having temperatures in the range 35,000 to 40,000 kelvin but are also much fainter than most stars.<ref name=britannica/>
==Formation==
Secular Science states that planetary nebulae are formed when [[red giant]] stars shed their outer layers to become [[white dwarf]]s, producing a large gas cloud surrounding the star.<ref>[https://www.space.com/17715-planetary-nebula.html Planetary nebula] from space.com</ref> However this would require millions of years, much longer than the [[Young earth creationism|6,000 years]] suggested by the [[Bible]] and by other [[Arguments for a recent creation|evidence]]. Instead [[Creation science|creation scientists]] suggest that [[God]] created planetary nebulae along with stars and [[planet]]s on the forth day of [[creation week]] ([[Genesis 1-8 (Translated)|Genesis 1:16]]).<ref>[https://answersingenesis.org/astronomy/the-splendor-of-gods-creation/ The Splendor of God's Creation] from answersingenesis.org </ref>
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]
==History==
The first observation of a planetary nebula was by [[Charles Messier]].<ref name=seds/> In 1764, Messier observed the [[Dumbbell nebula]]. Five years later, Messier observed the [[Ring nebula]]. His colleague, Pierre Méchain, discovered two more in 1780 and 1781, [[Little dumbbell nebula]] and the [[Owl nebula]]. These are the four planetary nebulae in the [[Messier catalogue]].
The term "planetary nebula" was coined by [[William Herschel]] in 1784/1785 as he believed them appear like the [[planet]] [[Uranus]] which he had recently discovered.<ref name=seds/> Hershel went on to discover a further 33 planetary nebulae through his systematic observation of the night sky.
==Properties==
Planetary nebulae are normally much smaller than other nebulae, having radii of order 1 [[light year]] and a mass of 0.3 solar masses.<ref name=britannica/> Most contain a [[star]] which ionizes the surrounding gas creating spectacular colours. The nebulae tend contain large quantities of [[element]]s heavier than [[helium]] such as [[carbon]] and [[oxygen]]. These different elements are responsible for the wide variety of colours in planetary nebulae. The abundance of each element varies from one nebula to another. Some nebulae also contain dust.
For most planetary nebulae, the star at the centre is a [[white dwarf]].<ref name=britannica/> These are small stars but extremely dense, having densities of over a billion kg/m<sup>3</sup>.<ref>[https://imagine.gsfc.nasa.gov/science/objects/dwarfs2.html White dwarfs] from imagine.gsfc.nasa.gov</ref> They are also extremely hot, having temperatures in the range 35,000 to 40,000 kelvin but are also much fainter than most stars.<ref name=britannica/>
==Formation==
Secular Science states that planetary nebulae are formed when [[red giant]] stars shed their outer layers to become [[white dwarf]]s, producing a large gas cloud surrounding the star.<ref>[https://www.space.com/17715-planetary-nebula.html Planetary nebula] from space.com</ref> However this would require millions of years, much longer than the [[Young earth creationism|6,000 years]] suggested by the [[Bible]] and by other [[Arguments for a recent creation|evidence]]. Instead [[Creation science|creation scientists]] suggest that [[God]] created planetary nebulae along with stars and [[planet]]s on the forth day of [[creation week]] ([[Genesis 1-8 (Translated)|Genesis 1:16]]).<ref>[https://answersingenesis.org/astronomy/the-splendor-of-gods-creation/ The Splendor of God's Creation] from answersingenesis.org </ref>
==References==
{{reflist}}
{{Nebulae}}
[[Category:Astronomy]]
[[Category:Nebulae]]