你知道这些冬至科普小知识吗？全国人民冬至又都在吃啥？
Winter solstice: things you should know about the shortest day of the year
在冬至这一天,北半球白昼最短,夜晚最长.南半球正相反.
美国哥伦比亚广播新闻邀请马萨诸塞大学天文学家史蒂芬•施奈德解释冬至的天文学成因,他向我们解答了大家需要知道的六个基本的冬至小知识.
What is the winter solstice, and why do we have it?
什么是冬至？为什么有冬至这个节气？
"Earth's axis is tilted 23.5 degrees relative to its orbit, and on December 21, Earth will be at the point in its orbit when the North Pole is tilted at its maximum away from the sun," Schneider told CBS News. "The effect of this in the Arctic is completely in darkness as Earth spins that day."
施奈德说："地轴相对于自转轨道的倾角为23.5度.12月21日,地球的北极距离太阳最远.这会导致当天北极圈地区完全见不到太阳."
For those of us in the Northern Hemisphere, it's the day with the shortest amount of daylight — less than 12 hours — and our longest night of the year. However, that's not the case for everyone. While it's winter for those of us in the Northern Hemisphere, people in the Southern Hemisphere experience it as their summer solstice with the longest stretch of daylight.
对北半球的人们来说,冬至这一天白昼最短,不到12小时,夜晚最长.但并不是对所有人都这样.北半球经历寒冬时,南半球在这一天迎来白昼最长的夏至日.
When does the winter solstice occur?
冬至在哪天？
The Earth's North Pole will be tilted farthest from the sun at 11:27 am ET on Thursday, Dec. 21, 2017, according to the National Weather Service.
根据美国国家气象局的数据,今年的冬至发生在美国东部时间2025-08-02上午11点27分（北京时间2025-08-02零点27分）,此时北极距离太阳最远.
Why isn't the winter solstice on the same day each year?
为什么每年的冬至都不是同一天？
The date of the winter solstice varies from year to year for people in different time zones. It typically occurs around Dec. 21 or 22, though on rare occasions it can be as early as Dec. 20 or as late as Dec. 23, according to the Weather Channel.
根据天气频道的数据,对不同时区的人们来说,冬至的日期每年会有变化.多数年份的冬至日都在12月21日或者22日,偶尔提早到20日,或者错后到23日.
That's because our calendars aren't a precise match to the solar year.
这是因为日历与阳历并非完全吻合.
Schneider writes: "Earth takes about 365 1/4 days to orbit the Sun. Next year, the moment of the solstice will be about 6 hours later at 5:23 pm ET. In 2019, it will be at 11:19 pm ET, so for people living in Puerto Rico and other time zones to the east, the date of the solstice will be on the 22nd."
施奈德写道："地球围绕太阳公转周期为365又1/4天.明年的冬至比今年大约迟6个小时（美国东部时间下午5点23分）,后年又推后到美国东部时间晚上11点19分.所以对于居住在波多黎各及以东时区的人们来说,冬至日期是22日."
