美不勝收 澳大利亞現罕見雨幡洞雲
Amazing photographs have emerged capturing one of the sky’s rarer sights – a cloud formation known as a fallstreak hole.
這些精彩照片拍下了一種罕見的天象——雨幡洞雲。
Also known as a ‘hole punch cloud’ the unusual occurrence, which appears in the sky as an ethereal groove gently capturing a mini-rainbow, is formed when tiny water droplets freeze suddenly into ice crystals and drop rapidly through the air, leaving behind the appearance of a hole.
這一現象又稱穿洞雲，看起來像空中飄蕩的盛有迷你彩虹的轍印。這一現象的成因是空中的小水滴迅速凍結成冰晶，墜落時在雲中留下了一個空洞。
Residents of seaside town Wonthaggi, in Victoria, australia, were quick to take to social media to capture the unusual event at around lunchtime yesterday.
澳大利亞維多利亞省的海邊小鎮旺薩吉居民昨天中午通過社交媒體迅速捕捉到這一稀有現象。
As well as admiring the beautiful shape, some citizens were concerned this could herald the end of the world with one tweeting: "Rapture's here, folks."
人們雖然欣賞雲洞的美麗，卻也擔心這是世界末日的前兆。有人在推特上寫到：“兄弟們，天國近了。”
小編注：被提（Rapture）是指世界末日時，或者的基督徒會被送上天與基督同在。
Fortunately, it was nothing so exciting.
幸運的是，什麼都沒發生。
Fallstreak holes happen usually in high or mid-level clouds, which are composed of water droplets that are already at a temperature colder than freezing.
雨幡洞雲通常發生在中高空雲層。那裏的水滴溫度低於冰點。
These ‘supercool’ droplets are frozen when – for example – a plane passes through the cloud and brings with it ice crystals which causes the water droplets to freeze. This process is known as seeding according to Science Magazine.
這些過冷液滴在遇到小冰晶時會凍結。例如一架飛機飛過後就會如此。《科學》雜誌把這一過程稱爲“播種”。
