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'''Solar energy''', [[radiant]] [[light]] and [[heat]]  from the [[sun]], has been harnessed by [[humans]] since [http://en.wikipedia.org/wiki/Ancient_history ancient times] using a range of ever-evolving [[technologies]]. Solar [http://en.wikipedia.org/wiki/Non-ionizing_radiation radiation], along with secondary solar-powered [[resources]] such as [http://en.wikipedia.org/wiki/Wind_power wind]  and [http://en.wikipedia.org/wiki/Wave_power wave power], [http://en.wikipedia.org/wiki/Hydroelectricity hydroelectricity] and [http://en.wikipedia.org/wiki/Biomass biomass], account for most of the available [http://en.wikipedia.org/wiki/Renewable_energy renewable energy] on [[earth]]. Only a minuscule [[fraction]] of the available solar energy is used.

'''Solar energy''', [[radiant]] [[light]] and [[heat]]  from the [[sun]], has been harnessed by [[humans]] since [https://en.wikipedia.org/wiki/Ancient_history ancient times] using a range of ever-evolving [[technologies]]. Solar [https://en.wikipedia.org/wiki/Non-ionizing_radiation radiation], along with secondary solar-powered [[resources]] such as [https://en.wikipedia.org/wiki/Wind_power wind]  and [https://en.wikipedia.org/wiki/Wave_power wave power], [https://en.wikipedia.org/wiki/Hydroelectricity hydroelectricity] and [https://en.wikipedia.org/wiki/Biomass biomass], account for most of the available [https://en.wikipedia.org/wiki/Renewable_energy renewable energy] on [[earth]]. Only a minuscule [[fraction]] of the available solar energy is used.

Solar powered [[electrical]] generation relies on [[heat]] engines and [http://en.wikipedia.org/wiki/Photovoltaics photovoltaics]. Solar energy's uses are [[limited]] only by [[human]] [[Invention|ingenuity]]. A partial list of solar [[applications]] includes space heating and cooling through [http://en.wikipedia.org/wiki/Solar_architecture solar architecture], [http://en.wikipedia.org/wiki/Potable_water potable water] via distillation and disinfection, [http://en.wikipedia.org/wiki/Daylighting daylighting], [http://en.wikipedia.org/wiki/Solar_hot_water solar hot water], [http://en.wikipedia.org/wiki/Solar_cooking solar cooking], and high [[temperature]] [[process]] [[heat]] for industrial purposes.To [[harvest]] the solar energy, the most common way is to use [http://en.wikipedia.org/wiki/Solar_panel solar panels].

Solar powered [[electrical]] generation relies on [[heat]] engines and [https://en.wikipedia.org/wiki/Photovoltaics photovoltaics]. Solar energy's uses are [[limited]] only by [[human]] [[Invention|ingenuity]]. A partial list of solar [[applications]] includes space heating and cooling through [https://en.wikipedia.org/wiki/Solar_architecture solar architecture], [https://en.wikipedia.org/wiki/Potable_water potable water] via distillation and disinfection, [https://en.wikipedia.org/wiki/Daylighting daylighting], [https://en.wikipedia.org/wiki/Solar_hot_water solar hot water], [https://en.wikipedia.org/wiki/Solar_cooking solar cooking], and high [[temperature]] [[process]] [[heat]] for industrial purposes.To [[harvest]] the solar energy, the most common way is to use [https://en.wikipedia.org/wiki/Solar_panel solar panels].

Solar [[technologies]] are broadly characterized as either [http://en.wikipedia.org/wiki/Passive_solar passive solar] or [http://en.wikipedia.org/wiki/Active_solar active solar] depending on the way they capture, [[convert]] and [[distribute]] solar energy. Active solar [[techniques]] include the use of photovoltaic panels and [http://en.wikipedia.org/wiki/Solar_thermal_energy solar thermal collectors] to harness the [[energy]]. Passive solar techniques include [[orienting]] a building to the [[Sun]], selecting [[materials]] with favorable [http://en.wikipedia.org/wiki/Thermal_mass thermal mass] or [[light]] [https://nordan.daynal.org/wiki/images/Light_dispersion_conceptual.gif dispersing] properties, and [[designing]] spaces that [[naturally]] [[circulate]] air.

Solar [[technologies]] are broadly characterized as either [https://en.wikipedia.org/wiki/Passive_solar passive solar] or [https://en.wikipedia.org/wiki/Active_solar active solar] depending on the way they capture, [[convert]] and [[distribute]] solar energy. Active solar [[techniques]] include the use of photovoltaic panels and [https://en.wikipedia.org/wiki/Solar_thermal_energy solar thermal collectors] to harness the [[energy]]. Passive solar techniques include [[orienting]] a building to the [[Sun]], selecting [[materials]] with favorable [https://en.wikipedia.org/wiki/Thermal_mass thermal mass] or [[light]] [https://nordan.daynal.org/wiki/images/Light_dispersion_conceptual.gif dispersing] properties, and [[designing]] spaces that [[naturally]] [[circulate]] air.

==Energy from the Sun==

==Energy from the Sun==

The [[Earth]] receives 174 [http://en.wikipedia.org/wiki/Orders_of_magnitude_(power)#petawatt_.281015_watts.29 petawatts] (PW) of incoming solar [[radiation]] (insolation) at the upper [[atmosphere]]. Approximately 30% is [[reflected]] back to [[space]] while the rest is absorbed by clouds, [[oceans]] and land masses. The [[spectrum]] of solar light at the [[Earth]]'s [[surface]] is mostly spread across the [[visible]] and [http://en.wikipedia.org/wiki/Near-infrared near-infrared] ranges with a small part in the [http://en.wikipedia.org/wiki/Near-ultraviolet near-ultraviolet].

The [[Earth]] receives 174 [https://en.wikipedia.org/wiki/Orders_of_magnitude_(power)#petawatt_.281015_watts.29 petawatts] (PW) of incoming solar [[radiation]] (insolation) at the upper [[atmosphere]]. Approximately 30% is [[reflected]] back to [[space]] while the rest is absorbed by clouds, [[oceans]] and land masses. The [[spectrum]] of solar light at the [[Earth]]'s [[surface]] is mostly spread across the [[visible]] and [https://en.wikipedia.org/wiki/Near-infrared near-infrared] ranges with a small part in the [https://en.wikipedia.org/wiki/Near-ultraviolet near-ultraviolet].

[[Earth]]'s land [[surface]], [[oceans]] and [[atmosphere]] absorb solar radiation, and this raises their [[temperature]]. Warm air containing evaporated [[water]] from the [[oceans]] rises, causing [[atmospheric]] [[circulation]] or [http://en.wikipedia.org/wiki/Convection convection]. When the air reaches a high altitude, where the [[temperature]] is low, water vapor condenses into clouds, which rain onto the [[Earth]]'s [[surface]], completing the [http://en.wikipedia.org/wiki/Water_cycle water cycle]. The latent [[heat]] of water condensation amplifies convection, producing atmospheric [[phenomena]] such as [[wind]], [http://en.wikipedia.org/wiki/Cyclone cyclones] and [http://en.wikipedia.org/wiki/Anti-cyclone anti-cyclones]. Sunlight absorbed by the [[oceans]] and land masses keeps the [[surface]] at an [[average]] [[temperature]] of 14 °C.[4] By [http://en.wikipedia.org/wiki/Photosynthesis photosynthesis] green plants convert solar [[energy]] into [[chemical]] energy, which produces [[food]], wood and the biomass from which [http://en.wikipedia.org/wiki/Fossil_Fuels fossil fuels] are derived.

[[Earth]]'s land [[surface]], [[oceans]] and [[atmosphere]] absorb solar radiation, and this raises their [[temperature]]. Warm air containing evaporated [[water]] from the [[oceans]] rises, causing [[atmospheric]] [[circulation]] or [https://en.wikipedia.org/wiki/Convection convection]. When the air reaches a high altitude, where the [[temperature]] is low, water vapor condenses into clouds, which rain onto the [[Earth]]'s [[surface]], completing the [https://en.wikipedia.org/wiki/Water_cycle water cycle]. The latent [[heat]] of water condensation amplifies convection, producing atmospheric [[phenomena]] such as [[wind]], [https://en.wikipedia.org/wiki/Cyclone cyclones] and [https://en.wikipedia.org/wiki/Anti-cyclone anti-cyclones]. Sunlight absorbed by the [[oceans]] and land masses keeps the [[surface]] at an [[average]] [[temperature]] of 14 °C.[4] By [https://en.wikipedia.org/wiki/Photosynthesis photosynthesis] green plants convert solar [[energy]] into [[chemical]] energy, which produces [[food]], wood and the biomass from which [https://en.wikipedia.org/wiki/Fossil_Fuels fossil fuels] are derived.

The total solar energy absorbed by [[Earth]]'s [[atmosphere]], [[oceans]] and land masses is approximately 3,850,000 [http://en.wikipedia.org/wiki/Joule#Multiples exajoules] (EJ) per year. In 2002, this was more [[energy]] in one hour than the world used in one year. Photosynthesis captures approximately 3,000 EJ per year in biomass. The amount of solar energy reaching the [[surface]] of the [[planet]] is so vast that in one year it is about twice as much as will ever be obtained from all of the [[Earth]]'s non-renewable resources of coal, oil, natural gas, and mined uranium combined.[http://en.wikipedia.org/wiki/Solar_energy]

The total solar energy absorbed by [[Earth]]'s [[atmosphere]], [[oceans]] and land masses is approximately 3,850,000 [https://en.wikipedia.org/wiki/Joule#Multiples exajoules] (EJ) per year. In 2002, this was more [[energy]] in one hour than the world used in one year. Photosynthesis captures approximately 3,000 EJ per year in biomass. The amount of solar energy reaching the [[surface]] of the [[planet]] is so vast that in one year it is about twice as much as will ever be obtained from all of the [[Earth]]'s non-renewable resources of coal, oil, natural gas, and mined uranium combined.[https://en.wikipedia.org/wiki/Solar_energy]

[[Category: Physics]]

[[Category: Physics]]