The value of the EM radiation we receive from the Universe can be realized by considering the following: Temperatures in the Universe today range from 1010$10^{10}$ Kelvin to 2.7$2.7$ Kelvin (in the cores of stars going supernova and in intergalactic space, respectively). Densities range over 45 orders of magnitude between the centers of neutron stars to the virtual emptiness of intergalactic space. Magnetic field strengths can range from the 1013$10^{13}$ Gauss fields around neutron stars to the 1 Gauss fields of planets such as Earth to the 10-7$10^{-7}$ Gauss fields of intergalactic space. It is not possible to reproduce these enormous ranges in a laboratory on Earth and study the results of controlled experiments; we must use the Universe as our laboratory in order to see how matter and energy behave in these extreme conditions.
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That's what makes the Sun burn or fuse, that's isthose are the nuclear reactionformulas of the nuclear reactions occurring in the Sun.
It is important to know that the Sun is not a Lambertian radiator (a circular disk of evenly emitted light). The Sun is not spherical but is instead described variously as a flattened disk, a quadrupole or a hexadecapole shape. Because it is mostly gaseous and liquid, with a solid core, each onion ring layer rotates at a different speed as does each latitude; this means different intensities of different wavelengths are emitted from different portions at different times, in both short period (minutes) variations and 11 year cycles - also sunspots and prominences alter the intensity of light at various wavelengths (black sunspots are cooler and brightly emit X-rays and high-energy particles).
Shape of the Sun:
More information: Using Precise Solar Limb Shape Measurements to Study the Solar Cycle - By: J. R. Kuhn, L. E. Floyd, Claus Fröhlich, et. al. - Jan 2000.
In addition the brightness is affected in a more easily visible manner by what is called Limb Darkening (oversimplified that means that the edges of the Sun are thin and can't emit as much visible light as the central portion). A slightly more complicated explanation comes from Wikipedia's Limb Darkening Article, or for Doctoral Astrophysics see H. H. Plaskett's Limb darkening and solar rotation or this more recent (and readable) Article Max Planck Institute Article on Solar Variance.
This is how the intensity varies based on latitudes:
Note that measurement is for a specific range of visible light and does not apply longitudinally. What constitutes lateral and longitudinal on the Sun is determined by the Sun's Axis, which is determined by it's Magnetic Field, which varies with the flow of the undercurrents of the various layers.
In general light is emitted similarly to what a camera records during a Solar Eclipse, this is a grossly oversimplified explanation:
That explains how the light is created (including light, energy waves, that are not visible to the human eye) and how it's intensity varies based on location, angle, time, etc. that it is viewed. The actual color of a Sun is determined by it's temperature, see here for more information on spectrum and color vs. temperature (why are there no green Suns): https://science.nasa.gov/ems/09_visiblelight .
Note how the Atmosphere creates 'windows' or filters that only allow certain wavelengths to penetrate a certain distance. Only visible light and a particular band of radio frequencies can penetrate all the way to the Earth's surface.
That's what makes the Sun burn or fuse, that's is the nuclear reaction of the Sun.
That's what makes the Sun burn or fuse, those are the formulas of the nuclear reactions occurring in the Sun.
It is important to know that the Sun is not a Lambertian radiator (a circular disk of evenly emitted light). The Sun is not spherical but is instead described variously as a flattened disk, a quadrupole or a hexadecapole shape. Because it is mostly gaseous and liquid, with a solid core, each onion ring layer rotates at a different speed as does each latitude; this means different intensities of different wavelengths are emitted from different portions at different times, in both short period (minutes) variations and 11 year cycles - also sunspots and prominences alter the intensity of light at various wavelengths (black sunspots are cooler and brightly emit X-rays and high-energy particles).
Shape of the Sun:
More information: Using Precise Solar Limb Shape Measurements to Study the Solar Cycle - By: J. R. Kuhn, L. E. Floyd, Claus Fröhlich, et. al. - Jan 2000.
In addition the brightness is affected in a more easily visible manner by what is called Limb Darkening (oversimplified that means that the edges of the Sun are thin and can't emit as much visible light as the central portion). A slightly more complicated explanation comes from Wikipedia's Limb Darkening Article, or for Doctoral Astrophysics see H. H. Plaskett's Limb darkening and solar rotation or this more recent (and readable) Article Max Planck Institute Article on Solar Variance.
This is how the intensity varies based on latitudes:
Note that measurement is for a specific range of visible light and does not apply longitudinally. What constitutes lateral and longitudinal on the Sun is determined by the Sun's Axis, which is determined by it's Magnetic Field, which varies with the flow of the undercurrents of the various layers.
In general light is emitted similarly to what a camera records during a Solar Eclipse, this is a grossly oversimplified explanation:
That explains how the light is created (including light, energy waves, that are not visible to the human eye) and how it's intensity varies based on location, angle, time, etc. that it is viewed. The actual color of a Sun is determined by it's temperature, see here for more information on spectrum and color vs. temperature (why are there no green Suns): https://science.nasa.gov/ems/09_visiblelight .
Note how the Atmosphere creates 'windows' or filters that only allow certain wavelengths to penetrate a certain distance. Only visible light and a particular band of radio frequencies can penetrate all the way to the Earth's surface.