《认识我们的地球》ppt课件

《《认识我们的地球》ppt课件》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、认识我们的地球想一想，你们了解地球家园的哪些信息呢？试着给大家分享一些吧！一、地球在宇宙中的位置总星系—河外星系银河系—其他星系太阳系—七大行星地月系—地球仰望星空总星系是指用现有的观测手段和方法，所能被人们观测和探测到的全部宇宙间范围。现在认为，其半径为150亿光年，年龄为150亿年，所包含的星系在10亿个以上。银河系银河系是太阳系所在的恒星系统，包括一千二百亿颗恒星和大量的星团、星云，还有各种类型的星际气体和星际尘埃。它的直径约为100,000多光年，中心厚度约为12,000光年，总质量是太阳质量的1400亿倍。太阳系太阳系就是我们现在所

2、在的恒星系统。它是以太阳为中心，和所有受到太阳引力约束的天体的集合体：8颗行星、至少165颗已知的卫星，和数以亿计的太阳系小天体。水星金星地球火星木星土星天王星海王星我的家庭成员，你们都认识吗？地月系地球与月球构成了一个天体系统，称为地月系。在地月系中，地球是中心天体，因此一般把地月系的运动描述为月球对于地球的绕转运动。daqing.99114.com/pifa-117/daqing.99114.com/pifa-115/daqing.99114.com/pifa-116/yichunshi.99114.com/pifa-128/yichun

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