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The Sun's atmosphere is composed of five layers: the photosphere, the chromosphere, the transition region, the corona, and the heliosphere. The coolest layer of the Sun is a temperature minimum region extending to about 500 km above the photosphere, and has a temperature of about 4,100 K. [77]
Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's gold. The color has also led to the nicknames brass, brazzle, and brazil, primarily used to refer to pyrite found in coal. [8] [9] The name pyrite is derived from the Greek πυρίτης λίθος (pyritēs ...
When the concentration of oxygen molecules in the atmosphere reached 1% of the present level, the chemical reactions during weathering were much like they are today. Siderite and pyrite were replaced by the iron oxides magnetite and hematite; dissolved Fe 2+ ions that had been carried out to sea were now deposited in extensive banded iron ...
The study of Earth's atmosphere and its processes is called atmospheric science (aerology), and includes multiple subfields, such as climatology and atmospheric physics. Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann. [4] The study of historic atmosphere is called paleoclimatology.
The core of the Sun is considered to extend from the center to about 0.2 of the solar radius (139,000 km; 86,000 mi). [1] It is the hottest part of the Sun and of the Solar System. It has a density of 150,000 kg/m 3 (150 g/cm 3) at the center, and a temperature of 15 million kelvins (15 million degrees Celsius; 27 million degrees Fahrenheit). [2]
If the extraterrestrial solar radiation is 1,367 watts per square meter (the value when the Earth–Sun distance is 1 astronomical unit), then the direct sunlight at Earth's surface when the Sun is at the zenith is about 1,050 W/m 2, but the total amount (direct and indirect from the atmosphere) hitting the ground is around 1,120 W/m 2. [6]
Two main processes govern changes in the atmosphere: plants use carbon dioxide from the atmosphere, releasing oxygen and the breakdown of pyrite and volcanic eruptions release sulfur into the atmosphere, which oxidizes and hence reduces the amount of oxygen in the atmosphere. However, volcanic eruptions also release carbon dioxide, which plants ...
[30] [42] [43] As these are the two most abundant elements after hydrogen and helium, the Sun's metallicity is affected significantly. [ 43 ] [ 44 ] It is possible that CI chondrites may hold too many volatiles, and the matrix of CM chondrites (excluding chondrules , calcium–aluminium-rich inclusions , etc.), or bulk Tagish Lake, may be a ...