一个多世纪以来，今年是春天最早到来的一年

一个多世纪以来，今年是春天最早到来的一年

As if 2020 hasn’t already been the longest decade of our lives, we’re now told that spring is set to make its earliest arrival in 124 years.

似乎2020年还不是我们生命中最长的十年，我们现在被告知，这个春天将是124年里最早到来的一次。

This shift has largely to do with our quirky calendar system, resulting from more than a century of leap years and the impact of those extra days over time, according to the Farmer’s Almanac. Every year, it takes Earth 365.25 days to revolve around the Sun, according to NASA. In order to compensate for that extra quarter of a day, our calendar system adds an extra day, February 29, every four years or so.

据《农民年鉴》称，这种变化主要与我们古怪的历法体系有关，这是由一个多世纪的闰年和这些额外天数的影响造成的。据美国国家航空航天局称，地球每年绕太阳公转一周需要365.25天。为了弥补多出的1 / 4天，我们的日历系统每四年左右增加一天，即2月29日。

Madison Dapcevich

“To keep our yearly calendars consistent with our orbit around the Sun, every four years we add one day. That day is called a leap day, and the year it's added to is called a leap year,” writes the space agency.

“为了使我们的年历与我们围绕太阳的轨道一致，每四年我们增加一天。这一天被称为闰日，加上这一天的那一年被称为闰年。”

There’s a quick trick to determining whether a year will be one that leaps. If the last year is divisible by 20, like this year’s 2020, then we will add the extra day. But if it is divisible by 100, it skips a leap year. Hold up, there’s more. Under our current calendar system, most century years, for example, 1700, will skip February 29 unless the year is divisible by 400, which was the case in 2000. That last rule is what has put us in this earlier-than-usual spring equinox.

有一个快速的技巧可以判断这一年是否会是一个飞跃的一年。如果最后一年能被20整除，就像今年的2020年，那么我们将增加额外的一天。但是如果它能被100整除，它就跳过了一个闰年。等等，还有更多。在我们目前的日历系统中，大多数世纪年，例如1700年，将跳过2月29日，除非这一年能被400整除，这是2000年的情况。这最后一条就是让我们比平常更早进入春分的原因。

Illumination of the Earth during various seasons as the planet orbits around the Sun. The top position represents the spring equinox while the bottom shows the fall. The summer solstice is depicted on the left and the winter solstice the right. Gritsalak karalak/Shutterstock

Now to the astrophysics bit.

现在是天体物理学解释部分。

The axis of the Earth is tilted 23.4 degrees, which is what causes the cycle of our seasons. During part of the year, the Northern Hemisphere is tilted toward the Sun, positioning this part of the world closer to it and thus providing more heat (aka summer), while the Southern Hemisphere of our planet is tilted away. In six months, these seasons will again shift. But the spring and fall equinoxes mark two days a year when both hemispheres receive roughly the same amount of light from the Sun.

地球的地轴倾斜23.4度，这就是造成我们的季节循环的原因。在一年中的一部分时间里，北半球是斜向太阳的，这使得世界的这一部分离太阳更近，因此提供了更多的热量(也就是夏天)，而地球的南半球则是斜向太阳的。6个月后，这些季节将再次变换。但春秋分点标志着一年中的两天，两个半球接收到的太阳光线大致相同。

“Most years, the Spring Equinox is on the 20th or 21st. For the first time since 1896, it occurs on the 19th in all of the US time zones,” tweeted a WBAL-TV meteorologist Tony Pann in Baltimore, Maryland.

“大多数时候，春分是在20日或21日。这是自1896年以来的第一次，它于19日在美国所有时区发生。wbal电视台的气象学家托尼·潘恩在马里兰州巴尔的摩市发的一条推特上说。

The vernal equinox marks the moment the Sun crosses the equator from south to north, which occurs at 11:49 pm ET in the US and in the early hours of Friday, March 20, in the rest of the world. You can check Time and Date to see when your hometown will see its equinox.

春分标志着太阳从南到北穿过赤道的时刻，美国东部时间晚上11点49分，世界其他地区是3月20日星期五的凌晨。你可以查看时间和日期，看看什么时候你的家乡会看到春分。