While not everyone will have pondered the subject while staring out of the window during a flight, the question as to why aeroplanes have circular windows rather than square ones is interesting.
虽然不是每个人都会在飞行中凝视窗外的时候思索一个问题：为什么舷窗是圆形的而不是方形的。但这个问题很有趣。

Over the years, aerospace engineering has made huge leaps in aeroplane technology, meaning planes can carry more passengers and go faster. The planes have also changed shape to increase safety – including the windows.
多年来，航空航天工程在飞机技术上取得了巨大的飞跃，这意味着飞机可以运载更多的乘客，飞行速度更快。同时，为了提高飞机的安全性，飞机在外形上也做出了相应的改变。舷窗，便是变化之一。

In the 1950s, when jetliners were starting to become mainstream, the De Havilland Comet[1] came into fashion. With a pressurized cabin, it was able to go higher and faster than other aircraft.
20世纪50年代，喷气式客机开始成为主流，德·哈维兰“彗星”客机便是当时的主要机型。增压座舱的诞生使得喷气式飞机可以比其他飞机飞得更高更快。

[1] 德·哈维兰“彗星”客机，由英国哈维兰公司研发，于1949年出厂的喷气民航客机，是世界上第一种以喷气发动机为动力的民航客机。

However, the plane had square windows and in 1953 two planes fell apart in the air, killing 56 people in total.
然而，该机型舷窗是方形的，1953年，该机型两架客机在空中解体，共造成56人死亡。

The reason for the crashes? The windows.
悲剧发生的原因是什么？答案是：舷窗。

Where there’s a corner, there’s a weak spot. Windows, having four corners, have four potential weak spots, making them likely to crash under stress – such as air pressure.
哪里有拐角，哪里就有弱点。方形舷窗有四个角，就有着四个潜在的薄弱点，使它们很可能在压力作用下破裂，比如大气压力。

By curving the window, the stress that would eventually crack the window corner is distributed and the likelihood of it breaking is reduced.
因此，让窗缘线条弯曲，来分散窗口四角的压力，从而降低了窗户破碎的可能性。