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  • General

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  • 地球的形状

    Different phases of the Moon during a lunar eclipse showing gradual shadowing effect.
     

    What is a flat-earther?
    ::什么是平地人?

    Flat-earther is a term used to describe someone who believes something despite the evidence. Or who does not believe something despite the evidence. There are actually people who believe that Earth is flat. They say that  satellite  photos are faked. They believe that the Apollo Moon landings were faked. But there are very few people alive today who actually believe that Earth is flat. There are, however, plenty of people who can be called flat-earthers. These people believe (or disbelieve) something despite the evidence.
    ::平远的卫星是一个术语,用来描述有人相信有证据的东西。或者不相信有证据的东西。实际上有人相信地球是平坦的。他们说卫星照片是伪造的。他们相信阿波罗月球着陆是伪造的。但今天只有极少数人实际相信地球是平坦的。然而,有很多人可以被称为平远的。尽管有证据,这些人还是相信(或不信)某些东西。

    Earth’s Shape
    ::地球的形状

    As you walk around, the ground looks flat. So why do you think that Earth is round? The best reason is that we have pictures of Earth taken from space. These photos show that Earth is round. Astronauts aboard the Apollo 17 shuttle took this one, called “The Blue Marble” ( Figure   ). Earth looks like a giant blue and white ball.
    ::当你走来走去时,地面看起来是平的。所以你为什么认为地球是圆的?最好的理由是我们从空间拍摄了地球的照片。这些照片显示地球是圆的。阿波罗17号航天飞机上的宇航员拿走了这艘叫做“蓝色大理石”的航天飞机。地球看起来像一个巨大的蓝色和白色球。

    Photo of Earth from space showing blue oceans and white cloud patterns.
     
    This is how the Earth looks from space—like a blue and white marble.

    Did people only come to think that Earth is round when spacecrafts took photos? No! Even the ancient Greeks knew that Earth was round. They figured this out by observing the arc shape of the  shadow  on the Moon during a  lunar eclipse . Since Galileo, people can look through a telescope and see that the  planets   orbit  around the  . These bodies—the   and each of the planets—are round. If Earth is a planet, it is certainly round.
    ::人们只是以为宇宙飞船拍到照片时地球是圆的吗?不!即使古希腊人知道地球是圆的。他们通过观察月蚀期间月黑的月光阴影的弧形来理解这一点。自伽利略以来,人们可以通过望远镜观察行星环绕四周的行星。这些物体——这些行星和每个行星——都是圆的。如果地球是一个行星,它肯定是圆的。

    Another way to tell that Earth is round is to look at ships sailing off into the  . What do you see when you watch a tall ship sail over the horizon of the Earth? The bottom part of the ship disappears faster than the top part ( Figure   ). What would that ship look like if Earth were flat? No part of it would disappear before the other. It would all just get smaller as it moved farther away.
    ::另一种方法可以说明地球是圆的,就是看着驶入地球的船舶。当你看到一艘高高的船舶在地球的地平线上航行时,你看到了什么?船底部分的消失速度比顶部(图)要快。如果地球是平的,那艘船会是什么样子?它的一部分不会比另一部分消失。随着它更远的移动,它会变得更小。

    A silhouette of a sailing ship on the horizon with sunlight reflecting on water.
     
    Earth’s curvature is noticeable when objects at a distance are below the arc.

    Hemispheres
    ::半球

    Earth is a sphere (technically, an oblate spheroid, a bit squashed at the poles). As a sphere, it can be divided. Half of a sphere is a  hemisphere . Earth is divided into hemispheres: north, south, east, west ( Figure   ).
    ::地球是一个球体( 技术上说, 是一个斜人球, 有点压在极上 ) 。 作为球体, 它可以被分割。 半个球是一个半球。 地球被划分成一个半球: 北、 南、 东、 西( 图 ) 。

    Remember that the  equator  is the line that falls at 0°. North of the equator is the  Northern Hemisphere . South of the equator is the  Southern Hemisphere . The North Pole is at 90°N. So there are 90 degree lines in the Northern Hemisphere. The South Pole is 90°S. So there are 90 degree lines in the Southern Hemisphere.
    ::记住赤道是赤道北纬0°的线,北纬是北半球。南赤道南纬是南半球。北极在北纬90°。北纬90°。南纬90°。南纬90°。南纬90°。南纬90°。

    Earth also has an  Eastern Hemisphere  and a  Western Hemisphere . They are just made by humans so that locations can more easily be specified. The  Prime Meridian  is 0°  longitude  and passes through Greenwich, England. The International Date Line is the 180° meridian. The Eastern Hemisphere is east of the Prime Meridian to the International Date Line. It includes eastern Europe and Asia. The Western Hemisphere west of the Prime Meridian to the International Date Line. It includes western Europe and the Americas.
    ::地球也有一个东半球和一个西半球。 它们只是由人类制造, 以便更方便地指定位置。 总理的梅里迪安是0°的经度, 穿过英国格林威治。 国际日期线是180°的经度。 东半球是总理的梅里迪安东端, 到国际日期线, 包括东欧和亚洲。 总理的梅里迪安西半球到国际日期线。 它包括西欧和美洲。

    Map showing Earth's four hemispheres: Northern, Southern, Eastern, and Western.
     
    The Northern, Southern, Eastern, and Western Hemispheres are highlighted.

    Summary
    ::摘要

    • Ancient Greeks knew that Earth was round. They saw the shadow the planet cast on the Moon during a lunar eclipse.
      ::古希腊人知道地球是圆的 他们看到了月蚀时 行星投在月球上的阴影
    • Through a simple telescope, the other planets appear to be round. So Earth must be round.
      ::通过一个简单的望远镜,其他行星看起来是圆的。所以地球必须是圆的。
    • A boat does not get smaller with distance but sinks below the horizon. This is more evidence that Earth is round.
      ::一条船不会随着距离而缩小,而是沉入地平线以下。这更能证明地球是圆的。

    Review
    ::回顾

    1. Before   and spaceships, how did people know that Earth is round?
      ::之前和宇宙飞船 人们怎么知道地球是圆的?
    1. What would a ship sailing away from you look like if Earth were flat? If Earth were round?
      ::如果地球是平坦的, 一艘离你而去的船会是什么样子?如果地球是圆的呢?
    1. Define where the hemispheres are located: northern, southern, western, and eastern.
      ::界定半球的位置:北半球、南半球、西半球和东半球。

    Explore More
    ::探索更多

    Use the resource below to answer the questions that follow.
    ::利用以下资源回答以下问题。

    1. Is the formation of clouds of matter into flattened disks unique to our solar system?
      ::物质云形成成平坦的磁盘 是太阳系独有的吗?
    1. Why do the planets in our solar system orbit in approximately the same plane around the sun?
      ::为什么太阳系中的行星 绕着太阳运行的轨道 几乎是同一架飞机?
    1. What causes massive spinning clouds of debris in space to flatten out into a disc shape?
      ::是什么原因导致空间碎片的大规模旋转云层粉碎成盘形?