2019 December 22

Solstice Illuminated: A Year of Sky
Video Credit & Copyright:
Ken Murphy (MurphLab); Music: Ariel (Moby)

Explanation: Can you find which day is the winter solstice? Each panel shows one day. With 360 movie panels, the sky over (almost) an entire year is shown in time lapse format as recorded by a video camera on the roof of the Exploratorium museum in San Francisco, California. The camera recorded an image every 10 seconds from before sunrise to after sunset and from mid-2009 to mid-2010. A time stamp showing the local time of day is provided on the lower right. The videos are arranged chronologically, with July 28 shown on the upper left, and January 1 located about half way down. In the videos, darkness indicates night, blue depicts clear day, while gray portrays pervasive daytime cloud cover. Many videos show complex patterns of clouds moving across the camera’s wide field as that day progresses. The initial darkness in the middle depicts the delayed dawn and fewer daylight hours of winter. Although every day lasts 24 hours, nighttime lasts longest in the northern hemisphere in December and the surrounding winter months. Therefore, finding the panel with the longest night will locate the day of winter solstice — which happens to be today in the northern hemisphere. As the videos collectively end, sunset and then darkness descend first on the winter days just above the middle, and last on the mid-summer near the bottom.

Ken Murphy ( MurphLab ); Music: Ariel ( Moby )

说明: 这部影片的每一个嵌板显示一天,你能找出那天是冬至吗?其中共有360个嵌板,故这部由美国.加州.旧金山.探索博物馆屋顶一部录影相机所拍摄的缩时影片,呈现将近一年份的天空。从2009年中到2010年中,这部相机从日出前到日落后,每10秒记录一幅影像,影片右下角的时间码,显示了一天之中的当地时间。 这些影片是依日期排列,左上角是7月28日,而1月1日大约出现在中间。在这些影片里,漆黑是夜晚,蓝色代表艳阳天,灰色代表有云层笼罩的阴天。而许多嵌板显示在一天之中,有颇为复杂的云系飘过广角相机之视野。在中间一带的日子,影片开始时里头一片漆黑,代表那是较晚天亮日照较短的冬天。虽然每天都是24小时等长,但北半球在12月及前后的冬季月份里,黑夜较长。所以只要找到有最长夜晚的嵌板,就找到了冬至,而北半球的冬至也恰好出现在今天。在这些影片结束之时,日落和紧随在后的黑夜,较早降临在中间一带的冬日,而底端的仲夏则较晚天黑。