地球白天时间越来越长 670万年增加1分钟

 　　Earth's days are getting longer but you're not likely to notice any time soon — it would take about 6.7 million years to gain just one minute, according to a study published last Wednesday.

　　据上周三公布的一份报告显示，地球的白天时间正在变得越来越长，不过人类很难感觉到--因为大约要等670年才增加1分钟。

　　Over the past 27 centuries, the average day has lengthened¹ at a rate of about +1.8 milliseconds (ms) per century, a British research team concluded in the journal Proceedings² of the Royal Society A.

　　据英国一研究团队在《英国皇家学会学报》上发布的报告称，在最近的27个世纪里，每个世纪的白昼平均延长了大约1.8毫秒。

　　This was "significantly less", they said, than the rate of 2.3 ms per century previously³ estimated — requiring a mere⁴ 5.2 million years to add one minute.

　　该小组的研究人员明确指出，这“大大少于”之前被认为的每个世纪增加2.3毫秒。人们当时认为“只”需520万年就会增加一分钟。

　　地球白天时间越来越长 670万年增加1分钟

　　"It's a very slow process," study lead co-author Leslie Morrison, a retired⁵ astronomer⁶ with Royal Greenwich Observatory⁷, told AFP.

　　报告的作者之一、皇家格林尼治天文台退休天文学家莱斯.莫里森向法新社透露："这是一个非常缓慢的过程"。

　　"These estimates are approximate, because the geophysical forces operating on the earth's rotation⁸ will not necessarily be constant over such a long period of time," he specified⁹. "Intervening Ice Ages etcetera will disrupt these simple extrapolations."

　　他解释说，"这个预估只是相近的，因为推动地球自转的力量在如此长的一段时间内并非一成不变。冰河时代的干预等其他因素会打破这些简单的推理。"

　　The previous 2.3 ms estimate had been based on calculations of the moon's known earth-braking forces, causing the ocean tides.

　　之前估算的2.3秒的结果就是基于已知的月球引力引起海洋潮汐来预估的。

　　Factors which influence the earth's rotation include the moon's braking effect, earth's altering shape due to shrinking polar ice caps since the last Ice Age, electro-magnetic interactions between the mantle¹⁰ and core, and changes in the mean sea level, said the team.

　　该团队表示，影响地球转动的因素包括月球的制动力，自冰河世纪以来极地冰川消融造成的地球形状的改变，地幔和地核的电磁相互作用以及海平面的变化等。

1 lengthened   

（时间或空间）延长，伸长( lengthen的过去式和过去分词 )

参考例句：

• The afternoon shadows lengthened. 下午影子渐渐变长了。
• He wanted to have his coat lengthened a bit. 他要把上衣放长一些。

2 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

3 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

4 mere   

adj.纯粹的；仅仅，只不过

参考例句：

• That is a mere repetition of what you said before.那不过是重复了你以前讲的话。
• It's a mere waste of time waiting any longer.再等下去纯粹是浪费时间。

5 retired   

adj.隐退的，退休的，退役的

参考例句：

• The old man retired to the country for rest.这位老人下乡休息去了。
• Many retired people take up gardening as a hobby.许多退休的人都以从事园艺为嗜好。

6 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

7 observatory   

n.天文台，气象台，瞭望台，观测台

参考例句：

• Guy's house was close to the observatory.盖伊的房子离天文台很近。
• Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。

8 rotation   

n.旋转；循环，轮流

参考例句：

• Crop rotation helps prevent soil erosion.农作物轮作有助于防止水土流失。
• The workers in this workshop do day and night shifts in weekly rotation.这个车间的工人上白班和上夜班每周轮换一次。

9 specified   

adj.特定的

参考例句：

• The architect specified oak for the wood trim. 那位建筑师指定用橡木做木饰条。
• It is generated by some specified means. 这是由某些未加说明的方法产生的。

10 mantle   

n.斗篷，覆罩之物，罩子；v.罩住，覆盖，脸红

参考例句：

• The earth had donned her mantle of brightest green.大地披上了苍翠欲滴的绿色斗篷。
• The mountain was covered with a mantle of snow.山上覆盖着一层雪。