ASTR 1010 1st EditionExam #3 Study Guide Lectures: 13 - 17Lecture 13 (October 14)The EarthDescribe The Earth’s three layersThe 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/ cm3Lecture 14 (October 16) The Earth’s AtmosphereList the layers of Earth’s atmosphere in order (from closest to Earth to furthest) and describe each.- No Electric Charge- Troposphere: Closest to Earth; All weather occurs- Stratosphere: Constant temperature, calm- Ozonosphere: Important for our survival; Absorbs UV radiation- Electric Charge- Ionosphere: Electrically charged, reflects radio waves- Exosphere: Particles are in independent orbits about the Earth- Magnetosphere: region controlled by Earth’s magnetic fieldDefine components of the magnetic fieldA. Magnetic Field1. Main: Fluid metals of motion in the core, 80% of field2. Residual: Deposits of metallic materials in crust (mostly iron and nickels), 15%3. Atmospheric: rise/fall of Ionosphere, 1-5% of fieldDescribe why we only see 59% of the moon’s surface. Include definitions of the librations. - Synchronous orbit motion: Moon’s rotation is synchronized with orbital motion.- We see 59% of the moon because:- Lunar libration: A very slow oscillation, real or apparent, of a satellite as viewed from the larger celestial body around which it revolves.- Latitude libration: north and south rocking of the moon. Tilt of moon’s orbit with respect to equator- Longitude libration: East and West rocking. Elliptical orbitLecture 15 (October 21) The Moon’s PhasesDescribe each of the moon’s phases.- New Moon: the phase of the moon when it is in conjunction with the sun and invisible from earth, or shortly thereafter when it appears as a slender crescent.- Waxing Crescent: The word crescent refers to the phases where the moon is less than half illuminated. Paired with the word waxing, it means the amount of illuminated surface as seen from Earth is increasing- First Quarter: the instant, approximately one week after a new moon, when one half of the moon's disk is illuminated by the sun.- Waxing Gibbous: the sunlit portion of the moon is more than half and is still increasing- Full: the surface of the moon seen from Earth is fully illuminated.- Waning Gibbous: more than half of the moon is illuminated but the illuminated portion is decreasing,- Third Quarter: half of the moon facing the Earth is illuminated.- Waning Crescent: less than half of the moon is illuminated and is decreasing.Lecture 16 (October 23)EclipsesDescribe the conditions for a Lunar and Solar Eclipse.A. Lunar Eclipse- Moon moves into the shadow Earth casts. Only occurs at full moon.- Partial Lunar Eclipse: occur more often than total lunar eclipse: roughly every 18 months- Total Lunar Eclipse: lasts no more than 100 minutes- During TLE, the moon looks red due to a small amount of red light refracted through Earth’s atmosphereB. Solar Eclipse- Moon casts shadow on Earth. - Can only occur on New Moon, not each month because the tilt of the moon’s orbit is not in line with Earth- Penumbra: Partial shade- Umbra: Complete shadow- Partial Eclipse: Moon only covers up part of the sun (imperfect alignment)- Annular Eclipse: Perfectly aligned, but moon is too small to cover up sun. (near apogee)- Total Eclipse: Moon is large enough to cover sun. Lasts 7.5 minutes. (near perigee) Lecture 17 (October 28)Lunar FeaturesDescribe Maria and Craters.- Maria: large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions.- Three major Mares:a. Mare Imbriumb. Mare Crisiumc. Mare Tranquility- No Mare are present on the far side of the moon- Because of the location of the Mares, Maria must have formed before or during the synchronization of the moon- Craters: a large, bowl-shaped cavity on the moon, typically caused by an explosion or the impact of a meteorite or other celestial body*Extra Stuff Mentioned in LecturesPhase of Moon on 10.30.14First QuarterExtra Notes- Airglow: a glow in the night sky caused by caused by the collision of x-rays and charged particles from the Sun with atoms and molecules, especially of oxygen, sodium, and the hydroxyl radical (OH). Steadily diminishes throughout night.- Twilight glow: a dim light from the upper atmosphere caused by emissions from atoms and molecules ionized by solar radiation.Know how to find time based on the moon’s phase and