Changes

According to the [[materialism|materialist]] and [[uniformitarianism|uniformitarian]] view, what eventually became the solar system initially existed as a large, rotating [[cloud]] of [[dust]] and [[gas]], composed of hydrogen and helium produced in the [[Big Bang theory|Big Bang]] as well as small amounts of heavier [[element]]s. Around 4.57 billion years ago, the cloud began to contract, perhaps as a result of a [[shock wave]] from a nearby [[supernova]]. [[Inertia]] caused the rotating cloud to flatten into a disk. Most of the mass concentrated in the middle, and began to heat up. Eventually, the kinetic energy of the hydrogen was sufficient to overcome the [[electromagnetic]] repulsion between the protons, and fusion began. The resulting solar wind helped clear away much of the material which had not coalesced into planets or other orbiting bodies.<ref>"[http://www.tufts.edu/as/wright_center/cosmic_evolution/docs/text/text_plan_1.html Cosmic Evolution, Epoch 4: Planetary Evolution]." ''[http://www.tufts.edu/as/wright_center/cosmic_evolution/docs/splash.html Cosmic Evolution: From Big Bang to Humankind]'', Wright Center, [[Tufts University]]. Accessed March 6, 2008.</ref> The Sun is most likely a third-generation star, meaning it is in the latest generation.

According to the [[materialism|materialist]] and [[uniformitarianism|uniformitarian]] view, what eventually became the solar system initially existed as a large, rotating [[cloud]] of [[dust]] and [[gas]], composed of hydrogen and helium produced in the [[Big Bang theory|Big Bang]] as well as small amounts of heavier [[element]]s. Around 4.57 billion years ago, the cloud began to contract, perhaps as a result of a [[shock wave]] from a nearby [[supernova]]. [[Inertia]] caused the rotating cloud to flatten into a disk. Most of the mass concentrated in the middle, and began to heat up. Eventually, the kinetic energy of the hydrogen was sufficient to overcome the [[electromagnetic]] repulsion between the protons, and fusion began. The resulting solar wind helped clear away much of the material which had not coalesced into planets or other orbiting bodies.<ref>"[http://www.tufts.edu/as/wright_center/cosmic_evolution/docs/text/text_plan_1.html Cosmic Evolution, Epoch 4: Planetary Evolution]." ''[http://www.tufts.edu/as/wright_center/cosmic_evolution/docs/splash.html Cosmic Evolution: From Big Bang to Humankind]'', Wright Center, [[Tufts University]]. Accessed March 6, 2008.</ref> The Sun is most likely a third-generation star, meaning it is in the latest generation.

Eventually, in a few billion years the sun will have expended most of it's Hydrogen, causing the outer shell to push outward and cool, turning into a Red giant, and Helium begins to be fused into Carbon. At this stage, Venus and Mercury will have been consumed by the now Red-Giant star, and possibly earth as well. Once the helium has been fused into carbon, there will not be enough heat to continue fusion to even heavier elements (as in larger stars), the core will collapse and the outer shell will be pushed off and form a Planetary Nebula, with a White Dwarf, and eventually a Black Dwarf at it's heart.<ref>http://imagine.gsfc.nasa.gov/docs/teachers/lessons/xray_spectra/background-lifecycles.html</ref>

Eventually, in a few billion years the sun will have expended most of its Hydrogen, causing the outer shell to push outward and cool, turning into a Red giant, and Helium begins to be fused into Carbon. At this stage, Venus and Mercury will have been consumed by the now Red-Giant star, and possibly earth as well. Once the helium has been fused into carbon, there will not be enough heat to continue fusion to even heavier elements (as in larger stars), the core will collapse and the outer shell will be pushed off and form a Planetary Nebula, with a White Dwarf, and eventually a Black Dwarf at its heart.<ref>http://imagine.gsfc.nasa.gov/docs/teachers/lessons/xray_spectra/background-lifecycles.html</ref>

== Orbital characteristics and galactic relationships ==

== Orbital characteristics and galactic relationships ==

The first equation above is assumed to be the rate-limiting step. The neutrinos produced should have an energy of 0.26 MeV—too little energy to be detectable by current technology. But processes occurring after this step ought to produce higher-energy neutrinos that ''would'' be detectable. Such neutrinos have been detected, but at a flux much smaller than predicted. This indicates that the presumed rates for these subsequent processes are higher than the true rates, or else the neutrinos produced somehow transform to a different type of neutrino that would be unobservable. That in turn would imply that neutrinos ''do'' have rest mass.<ref name=Britannica/>

The first equation above is assumed to be the rate-limiting step. The neutrinos produced should have an energy of 0.26 MeV—too little energy to be detectable by current technology. But processes occurring after this step ought to produce higher-energy neutrinos that ''would'' be detectable. Such neutrinos have been detected, but at a flux much smaller than predicted. This indicates that the presumed rates for these subsequent processes are higher than the true rates, or else the neutrinos produced somehow transform to a different type of neutrino that would be unobservable. That in turn would imply that neutrinos ''do'' have rest mass.<ref name=Britannica/>

According to current models, some of this energy is transferred to the surface by convection in the outer 20-30% of the body of the sun.<ref name=sunspot1/> [[Helium]] in this ''convective zone'' rises to or near the surface, releases its heat, and then sinks back to the center. Helium absorbs radiation more readily than does hydrogen, and for that reason the Sun is always getting marginally brighter with the passage of time.<ref name=Britannica/>

According to current models, some of this energy is transferred to the surface by convection in the outer 20-30% of the body of the sun.<ref name=sunspot1/> Helium in this ''convective zone'' rises to or near the surface, releases its heat, and then sinks back to the center. Helium absorbs radiation more readily than does hydrogen, and for that reason the Sun is always getting marginally brighter with the passage of time.<ref name=Britannica/>

The remaining energy is transferred in the gamma photons, which must take a "random walk" to reach the corona of the sun. Current models suggest that the light generated by these processes takes 50 million years to reach the surface.<ref name=sunspot1/>

The remaining energy is transferred in the gamma photons, which must take a "random walk" to reach the corona of the sun. Current models suggest that the light generated by these processes takes 50 million years to reach the surface.<ref name=sunspot1/>