每日一词学英语(22): out of the blue

英国37岁飞行员Timothy Peake最近碰到一件意外的事儿，对他来讲是件天大的好事。
The British pilot named by the European Space Agency (ESA) today as one of its six new astronauts said that his selection had come out of the blue but is a dream come true. 梦想成真，而且是意外之喜。

这个词的意思一查就知道了：(idiomatic) unexpectedly; without warning or preparation
After I hadn’t heard from her in six months, she called me out of the blue to meet for lunch. 有六个月没联系了，有一天她忽然约我一起吃饭。
I really can't understand how something like this could simply pop up out of the blue. 实在想不明白这样的事情怎么一下子就发生了，连声招呼都不打？

Out of the blue这个词似乎很有吸引力，有很多影视剧、歌曲、专辑等文艺作品以它命名。