The Seasons(I)地球赤道面手公转轨道面的夹角是产生季节的原因北半球夏季=北半球冬季=南半球冬季南半球夏季23.5Sunlightspreedoonnortsnata:ttdirnnoranainTosunTosuSuntghtnearty directSunlightspreadounEarthat SummerSolsticeEarth atWinter Solstice2002nofThomsonLear02002Br00PutlisadiviaionofThoms
地球赤道面与公转轨道面的夹角 是产生季节的原因 北半球夏季 = 南半球冬季 北半球冬季= 南半球夏季 The Seasons (III)
The Seasons (IV)（椭率夸大了很多）Earth inEarth inJulyJanuarysunEarth's distancefromthe sunhasonlyaveryminorinfluenceonseasonaltemperaturevariations（地球到太阳的距离的变化对季节性温度变化影响非常小）
The Seasons (IV) sun Earth in Earth in July January Earth’s distance from the sun has only a very minor influence on seasonal temperature variations（地球 到太阳的距离的变化对季节性温度变化影响非常小）. （椭率夸大了很多）
The Motion of the Planets (I)The planets are orbiting the sun almostexactly intheplaneoftheecliptic（所有行星几乎都在黄道面）JupiterVenusMarsEarthMercuryThe moon is orbiting EarthinSaturnalmost the sameplane (ecliptic)
The Motion of the Planets (I) The planets are orbiting the sun almost exactly in the plane of the ecliptic （所有行星几乎都在黄道面）. The moon is orbiting Earth in almost the same plane (ecliptic). Venus Mercury
Apparent Motion of the Inner PlanetsMercuryappears at most ~28°Sunset,lookingwestfromthesun.（水星离太阳最远28度）VenusItcanoccasionallybeseenshortlyafter sunset inthewest orMercurybefore sunriseintheeast.Venus appears at most~ 46°fromthesun.Sunrise,lookingeast（金星离太阳最远46度）Itcanoccasionallybeseenforatmost a fewhours after sunsetinVenusthewestorbefore sunriseintheMercuryeast.Sun
Mercuryappears at most ~28º from the sun. （水星离太阳最远28度） It can occasionally be seen shortly after sunset in the west or before sunrise in the east. Venus appears at most ~ 46º from the sun. （金星离太阳最远46度） It can occasionally be seen for at most a few hours after sunset in the west or before sunrise in the east. Apparent Motion of the Inner Planets
Apparent Motion of the Inner PlanetsMercuryappearsatmost28°fromthesun.（水星离太阳最远28度。）SunOrbitof/MercuryMercuryOrbitofVenusappears atmost~46VenusVenusTransitOrbitoffromthesun.（金星离太阳最EarthTransit远46度。）EarthConjunctionOuterPlanetOrbitEarthOrbit外行星没有这个问题art
Mercury appears at most ~28ºfrom the sun.（水星离太 阳最远28度。） Venus appears at most ~ 46º from the sun. (金星离太阳最 远46度。） Apparent Motion of the Inner Planets 外行星没有这个问题