ASTR 1010 1st EditionLecture 13Outline of Last Lecture I. TelescopesA. DefinitionsB. TypesC. DiagramD. PowerE. InterferometryOutline of Current LectureI. EarthA. LayersB. AtmosphereCurrent LectureI. Earth- Earth’s atmosphere is dominated by Nitrogen Dioxide NO(¿¿2)¿- Organisms in the ocean destroy nitric acid present in the ocean- Earth’s rotation is slowing at a rate of 0.001 s /century❑- The moon’s orbit is slowly moving away from Earth at the same rateA. Layers- The Crust: It is the uppermost, out layer of the Earth. It is the layer we can see and feel.- Approximately 10-15 km thick- It is composed of a sedimentary layer, a granite layer, and a limestonelayer.- The density of the crust is approximately 3 g /cm3 (three times the density of water.- The Mantle: It is the middle layer- About 3,000 km thick- Made of silicate types of material- Density is about 5.5 g /cm3- The Core: The center of the Earth- About 3,500 km thick- Made of hot metals- Density is about 10−12 g/cm3B. Atmosphere- Primordial atmosphere: Earth’s first atmosphere.- Primarily made up of Hydrogen and Helium- Current atmosphere: secondary atmosphere- In order of abundance:-NO2-O2-C O2-C O❑-H2O-S
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