科学揭秘"暴风雨前的宁静"

Have you ever spent an afternoon in the backyard, maybe grilling or enjoying a basketball game, when suddenly you notice that everything goes quiet? The air seems still and calm—even the birds stop singing and quickly return to their nests.

你可曾有过这样的经历：某天下午正在后院烧烤或者打篮球的时候，突然发现一切瞬间变得安静下来，空气似乎凝结了，连鸟儿也不再歌唱而转身躲回窝里去了？

After a few minutes, you feel a change in the air, and suddenly a line of clouds ominously appears on the horizon—clouds with a look that tells you they aren't fooling around. You quickly dash in the house and narrowly miss the first fat raindrops that fall right before the downpour. At this moment, you might stop and ask yourself, "Why was it so calm and peaceful right before the storm hit?"

几分钟后，你感觉到空气中有所变化，忽然之间一排乌云出现在地平线上，让人有种不祥的预感——乌云的样子好像是在告诉你它们可不只是做做样子而已。你急冲进屋里，险些被瓢泼大雨前掉下的大雨点砸个正着。此时，你也许会停下来问自己：“为什么暴风雨来临前是那么宁静安详呢？”

It's an intriguing phenomenon that people have recognized for centuries, but what on earth causes this calm? And there is an old phrase "calm before the storm", often used in its figurative meaning—a quiet period just before a great activity or excitement. According to our own experience, we know there is literally calm before the storm. But what causes this calm? And is it always calm before the storm? Let's hear what scientists have to say.

人们在几个世纪前就已经发现这个神秘的现象了，但究竟是什么原因造成暴风雨前的这番宁静呢？古谚有云“暴风雨前的宁静”，这通常用在比喻的修辞中，描述热闹的活动以及情绪亢奋前的一段安静时间。根据自身的经验，我们也知道事实上暴风雨来临前也确实是宁静的。但这是什么原因造成的呢？暴风雨前总是平静么？让我们来听听科学家们的解释。

The answer is sometimes there is; sometimes there isn't. Under the right conditions, an eerie or peaceful calm will befall your picnic before a storm moves in. Other storms skip the calm and proudly announce their presence by instantly unleashing bad weather.

答案是：有时如此，有时则不然。在特定的情况下，暴风雨来临前会出现令人恐惧的或是祥和的寂静，降临在你野餐的时候。其他种类的暴风雨则直接跳过寂静的步骤，犹如在骄傲地宣布自己的存在一般，瞬间风雨大作。