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Solar radiation pressure strongly affects comet tails. Solar heating causes gases to be released from the comet nucleus, which also carry away dust grains. Radiation pressure and solar wind then drive the dust and gases away from the Sun's direction. The gases form a generally straight tail, while slower moving dust particles create a broader ...
The Eddington limit is obtained by setting the outward radiation pressure equal to the inward gravitational force. Both forces decrease by inverse-square laws, so once equality is reached, the hydrodynamic flow is the same throughout the star.
(Above the atmosphere, the result is even higher: 394 K (121 °C; 250 °F).) We can think of the earth's surface as "trying" to reach equilibrium temperature during the day, but being cooled by the atmosphere, and "trying" to reach equilibrium with starlight and possibly moonlight at night, but being warmed by the atmosphere.
In forming the stellar structure equations (exploiting the assumed spherical symmetry), one considers the matter density (), temperature (), total pressure (matter plus radiation) (), luminosity (), and energy generation rate per unit mass () in a spherical shell of a thickness at a distance from the center of the star.
Eddington assumed the pressure P in a star is a combination of an ideal gas pressure and radiation pressure, and that there is a constant ratio, β, of the gas pressure to the total pressure. Therefore, by the ideal gas law:
In the radiation zone gravity is balanced by the pressure on the gas coming from both itself (approximated by ideal gas pressure) and from the radiation. For a small enough stellar mass the latter is negligible and one arrives at T I ∝ M R {\displaystyle T_{I}\varpropto {\frac {M}{R}}} as before.
Our modern-day expert, weather.com senior meteorologist Chris Dolce, explains:. The white appearance of sunlight reaching the Earth actually comes to us in all colors of the rainbow, all of which ...
The energy produced by stars, a product of nuclear fusion, radiates to space as both electromagnetic radiation and particle radiation. The particle radiation emitted by a star is manifested as the stellar wind, [173] which streams from the outer layers as electrically charged protons and alpha and beta particles. A steady stream of almost ...