教育部重点推荐学科网站

帮助中心
微信登录,您好!有效期: 0 资金余额:
  • 会员中心 | 退出登录
  • 资金余额:
  • 可用:
  • 经验积分:
  • 待阅短信:
  • 待签文章:
  • 登录次数:

当前位置:首页 > 教学参考> 学生园地> 生活科普 > 内容详情

地球一直在转,所以是“永动机”?

作者:佚名  人气: 765 次  时间:2018年08月25日  星级:

根据中学物理知识,“永动机”是不可能制成的,因为不管是第一类还是第二类永动机,都违背了能量守恒定律(也可是说第二类永动机违背了热力学第二定律)!

可是,有人会说了,地球一直在绕着太阳转动,地球不就是个“永动机”么?

似乎有点道理哈,地球现在的确一直在转动啊。

那么,问题出来了:

虽然现在地球一直在围绕这太阳转动,但是,是不是会一直永远这么转动下去?如果不能,那就不是永动机!

另外最重要的是,永动机是用来做什么的?是用来对外做功的,或者说把动能转化为其他形式能的!可是地球能做到么?

按照生物理论,有生就有灭。

那么按照物理知识,怎么解答呢?

据科学家们测算,当前宇宙的年龄为136亿年左右,当前宇宙是在136亿年前的一次爆炸后产生的,各种大型星系相继产生,银河系大概的时间也和宇宙相仿。

我们会发现,所有的星系都有一个特征,就是所有的星星都在围绕中间质量最大的物质(一般是黑洞)转动,比如银河系。而太阳系这个小星系也是如此,有八大行星和无数小行星围绕太阳运转。

这八大行星都在做椭圆运动,由于每天都在绕着太阳转动,似乎会一直这么运动下去了。

但是,地球到底会不会一直围绕着太阳转呢?

那我们先来想一下地球当初为什么会围绕着地球转。

在有太阳的最初时期,很多的小型碎片或者说小行星都在四散高速运动,根据高中物理中牛顿的万有引力定律,万物之间都有引力存在,所以,这些小行星都受到了初期太阳的吸引力,但是,这些小行星距离太阳的远近不同,速度也不同。根据高中物理圆周运动的相关知识,物体要做圆周运动,必须有向心力。下面分为三种情况讨论一下:

1.当物体所需要的向心力大于外界能够提供的外力时,物体将做离心运动。此种情况下,一些行星逃离太阳系跑到宇宙空间中去了。由于动能转化为势能,动能会逐渐减小,逃了一段时间,速度降下来,由于惯性有的速度稍大还能持续前进,有的速度太小,导致无法逃离,在向心力作用下,又回到太阳系,从而围绕太阳做椭圆运动。

2.当物体所需要的向心力小于外界能够提供的外力时,物体将做向心运动。此种情况下,一些行星飞奔太阳而去,熔化了升华了。

3.当物体所需要的向心力等于外界能够提供的外力时,物体将做匀速圆周运动。此种情况下,一些行星围绕太阳做匀速圆周运动。由于各种复杂受力干扰因素等等,这种完美情况任何星系都不存在。

而太阳本身也是有寿命的,目前的太阳正处于壮年时期,太阳对于各个行星的引力也是随着时间而变化的,所以,八大行星的最终结局要么是飞向太阳,要么是逃离太阳系。也就是说,要么毁灭,要么逃离。

但是逃离后的结果呢?宇宙并不存在绝对的真空,只要没有被别的星系俘获,由于阻力作用,就会慢慢减速,最终还是要碰到必然事件而消亡。。。。。

太阳系如此,银河系如此,其他所有星系也都如此,每天不停的转啊转,奔跑啊跑,直到最后的灭亡。然后宇宙也最后塌缩灭亡,最终在一次次爆炸中,新的宇宙一次次重生,周而复始。。。 

用户评论

(以下评论仅代表网友意见,与本站立场无关)

网友评论共 0
[{"id":136,"name":"电子课本","url":"/wlzx/List_136.html","target":"_self",children: [{"id":137,"name":"人教版课本","url":"/wlzx/List_137.html","target":"_self",children: [{"id":140,"name":"人教八年级上册","url":"/wlzx/List_140.html","target":"_self"},{"id":141,"name":"人教八年级下册","url":"/wlzx/List_141.html","target":"_self"},{"id":142,"name":"人教九年级全册","url":"/wlzx/List_142.html","target":"_self"}] },{"id":138,"name":"沪科版课本","url":"/wlzx/List_138.html","target":"_self",children: [{"id":143,"name":"沪科八年级全册","url":"/wlzx/List_143.html","target":"_self"},{"id":144,"name":"沪科九年级全册","url":"/wlzx/List_144.html","target":"_self"}] },{"id":139,"name":"苏科版课本","url":"/wlzx/List_139.html","target":"_self",children: [{"id":160,"name":"新苏科版八年级上册","url":"/wlzx/List_160.html","target":"_self"},{"id":179,"name":"新苏科版八年级下册","url":"/wlzx/List_179.html","target":"_self"},{"id":185,"name":"新苏科版九年级上册","url":"/wlzx/List_185.html","target":"_self"},{"id":186,"name":"新苏科版九年级下册","url":"/wlzx/List_186.html","target":"_self"}] },{"id":145,"name":"沪粤版课本","url":"/wlzx/List_145.html","target":"_self",children: [{"id":154,"name":"新沪粤八年级上","url":"/wlzx/List_154.html","target":"_self"},{"id":155,"name":"新沪粤八年级下","url":"/wlzx/List_155.html","target":"_self"},{"id":159,"name":"新沪粤九年级上","url":"/wlzx/List_159.html","target":"_self"},{"id":162,"name":"新沪粤九年级下","url":"/wlzx/List_162.html","target":"_self"},{"id":146,"name":"沪粤八年级上册","url":"/wlzx/List_146.html","target":"_self"},{"id":147,"name":"沪粤八年级下册","url":"/wlzx/List_147.html","target":"_self"},{"id":148,"name":"沪粤九年级上册","url":"/wlzx/List_148.html","target":"_self"},{"id":149,"name":"沪粤九年级下册","url":"/wlzx/List_149.html","target":"_self"}] },{"id":150,"name":"北师大版课本","url":"/wlzx/List_150.html","target":"_self",children: [{"id":151,"name":"北师大版八年级上册","url":"/wlzx/List_151.html","target":"_self"},{"id":152,"name":"北师大版八年级下册","url":"/wlzx/List_152.html","target":"_self"},{"id":153,"name":"北师大版九年级","url":"/wlzx/List_153.html","target":"_self"}] },{"id":180,"name":"教科版电子课本","url":"/wlzx/List_180.html","target":"_self",children: [{"id":181,"name":"教科版八年级上册","url":"/wlzx/List_181.html","target":"_self"},{"id":182,"name":"教科版八年级下册","url":"/wlzx/List_182.html","target":"_self"},{"id":183,"name":"教科版九年级上册","url":"/wlzx/List_183.html","target":"_self"},{"id":184,"name":"教科版九年级下册","url":"/wlzx/List_184.html","target":"_self"}] },{"id":187,"name":"上教版电子课本","url":"/wlzx/List_187.html","target":"_self",children: [{"id":188,"name":"上教版八年级上册课本","url":"/wlzx/List_188.html","target":"_self"},{"id":193,"name":"上教版八年级下册课本","url":"/wlzx/List_193.html","target":"_self"},{"id":189,"name":"上教版九年级上册课本","url":"/wlzx/List_189.html","target":"_self"},{"id":194,"name":"上教版九年级下册课本","url":"/wlzx/List_194.html","target":"_self"}] }] },{"id":1277,"name":"考试大纲","url":"/wlzx/List_1277.html","target":"_self",children: [{"id":1403,"name":"中考大纲","url":"/wlzx/List_1403.html","target":"_self"},{"id":1404,"name":"课程标准","url":"/wlzx/List_1404.html","target":"_self"}] },{"id":1278,"name":"教学研究","url":"/wlzx/List_1278.html","target":"_self",children: [{"id":1405,"name":"教学论文","url":"/wlzx/List_1405.html","target":"_self"},{"id":1406,"name":"课题研究","url":"/wlzx/List_1406.html","target":"_self"}] },{"id":1279,"name":"备课参考","url":"/wlzx/List_1279.html","target":"_self",children: [{"id":1407,"name":"参考资料","url":"/wlzx/List_1407.html","target":"_self",children: [{"id":27,"name":"声学参考资料","url":"/wlzx/List_27.html","target":"_self"},{"id":26,"name":"光学参考资料","url":"/wlzx/List_26.html","target":"_self"},{"id":28,"name":"热学参考资料","url":"/wlzx/List_28.html","target":"_self"},{"id":24,"name":"力学参考资料","url":"/wlzx/List_24.html","target":"_self"},{"id":25,"name":"电磁学参考资料","url":"/wlzx/List_25.html","target":"_self"},{"id":29,"name":"综合知识资料库","url":"/wlzx/List_29.html","target":"_self"}] },{"id":1408,"name":"物理图库","url":"/wlzx/List_1408.html","target":"_self",children: [{"id":62,"name":"声热学图片","url":"/wlzx/List_62.html","target":"_self"},{"id":61,"name":"光学图片","url":"/wlzx/List_61.html","target":"_self"},{"id":60,"name":"电磁学图片","url":"/wlzx/List_60.html","target":"_self"},{"id":59,"name":"力学图片","url":"/wlzx/List_59.html","target":"_self"}] }] },{"id":1280,"name":"实验探究","url":"/wlzx/List_1280.html","target":"_self",children: [{"id":1409,"name":"科学探究","url":"/wlzx/List_1409.html","target":"_self"},{"id":1410,"name":"物理实验室","url":"/wlzx/List_1410.html","target":"_self"}] },{"id":1281,"name":"物理广角","url":"/wlzx/List_1281.html","target":"_self",children: [{"id":1411,"name":"物理前沿","url":"/wlzx/List_1411.html","target":"_self"},{"id":1412,"name":"物理学家","url":"/wlzx/List_1412.html","target":"_self"}] },{"id":1282,"name":"学生园地","url":"/wlzx/List_1282.html","target":"_self",children: [{"id":1413,"name":"趣味物理","url":"/wlzx/List_1413.html","target":"_self"},{"id":1414,"name":"生活科普","url":"/wlzx/List_1414.html","target":"_self"},{"id":1416,"name":"学习指导","url":"/wlzx/List_1416.html","target":"_self"}] }]