水 从 何 来 ？

<span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">浊子上平静地放着一杯生水。城镇里的孩子肯定会说，这水是拧开自来水龙头，从水管子里流来的。村子里的孩子会说，这水是从河里挑回来，或从井下打上来的，因为他们那里还没有安装自来水。自来水厂是把从河流引来或从井里汲取的水，进行净化处理，使水质符合卫生标准后，再通过密布的水管网线供应千家万户的。河流里的地表水和井里的地下水，都是天上降落的雨雪水，经过地面汇集和土壤渗透而形成的。有的水流从高处向低处流淌，走了很远的路程。人们使用过的污水，往往也排放回河流。多数河流的水最终流入海洋。</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><br/></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">　　雨和雪水从何而来？简单地说，它们是空气里的水汽遇冷凝结而成的。当空气托不住它们的时候，就降落到地面。地球上分布着广阔的海洋，水分不停地从海面蒸发到空中，补充空气里的水分。这样，海洋蒸发</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">—</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">大气凝结</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">—</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">雨雪降落</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">—</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">河流汇集</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">—</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">回归海洋，形成了地球上周而复始、无始无终、无休无止的</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">“</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">水循环</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">”</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">。正是由于这个循环，地球上才生机勃勃，永葆青春。</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><br/></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">　　海洋里的水，最初从何而来？或者说，地球上的水从何而来？这个话题意<span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">味深长。据说，科学家们研究至今，关于地球水的形成有</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">30</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">多种说法。大致归纳起来，有原生说和外来说两大类。原生说认为，当初宇宙的尘埃云凝聚成地球时，随着地球快速的自转，含在熔融状态原始物质里的水分便向地表移动，最终逐渐释放出来，当地球表面温度降至</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="100" unitname="摄氏度"><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">100</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">摄氏度</span></chmetcnv><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">以下时，呈气态的水才凝结成雨降落到地面。这些过程大致发生在</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">35</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">亿年前。至今，地下岩浆中仍然含有大量的水分。火山喷发时，火山口的岩浆平均含水</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">6 %</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">，有的甚至达到</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">12 %</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">，就是原始物质含水的佐证。又据记载，著名的意大利维苏威火山在</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">1906</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">年喷发时，高压水蒸气柱高达</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="13000" unitname="米"><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">13000</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">米</span></chmetcnv><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">，持续了</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">20</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">多小时。因此，如果</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="40" unitname="公里"><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">40</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">公里</span></chmetcnv><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">厚的大陆壳，</span><chmetcnv wst="on" tcsc="0" numbertype="1" negative="False" hasspace="True" sourcevalue="6" unitname="公里"><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">6 </font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">公里</span></chmetcnv><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">厚的大洋壳都由岩浆凝结而成的话，释放的水量大体上与现代全球大洋的水量相当。目前每年仍有</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">660 </font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">多立方公里的原生水从地球内部逸放出来。</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><br/></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">　　外来说大约又分为两种情况，一种认为，地球诞生以来，每日都有大量的陨石降落到地球表面，从而源源不断地带来宇宙的水。其中，球粒陨石是最常见的一种陨石，其含水量一般为</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">0.5%</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">～</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">5%</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">，有的可达</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">10% </font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">以上。另一种认为，从太阳辐射来带正电的基本粒子</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">——</font></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">质子，与地球大气中的电子结合成氢原子，再与氧原子化合成水。</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><br/></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">　　原始的水经过几十亿年的演变，才成为今天的地球水，其成分和性质当然都发生了很大的变化，二者已不可同日而语了。</span><span lang="EN-US" style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><br/><br/></span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: 宋体; mso-ascii-font-family: ˎ̥; mso-hansi-font-family: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">作者：西园</span><span style="FONT-SIZE: 11.5pt; FONT-FAMILY: ˎ̥; mso-bidi-font-family: 宋体; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体;"><font face="宋体, MS Song">
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