VOA新闻杂志2024--What Would Happen without Leap Day?

What Would Happen without Leap Day?

This year, 2024, is a leap year. February 29 is known as "leap day." But what is behind this rare extra day on the calendar?

Everyone knows the Earth takes 365 days to travel around the sun. Well, that is not exactly correct. The Earth really takes 365 days, five hours, forty-eight minutes and forty-six seconds to complete its orbit around the sun.

So, almost every four years an extra day occurs and it is represented on the calendar.

The Jet Propulsion Laboratory at the California Institute of Technology says the extra day is used to be sure the months stay connected to yearly events such as equinoxes and solstices.

NASA says that over time, our seasons would fall out of order without the leap day. Each calendar year is about six hours longer than 365 days.

However, a leap day is not added every four years. That would lengthen¹ the calendar by 44 minutes, say experts at the National Air and Space Museum in Washington, D.C. Over time, that would mean summer would arrive in November, said Younas Khan, a physics instructor² at the University of Alabama, Birmingham.

So a leap day is added nearly every four years, but not in years including 1700, 1800 and 1900. There was a leap day in 2000 because it was a year divisible by both 100 and 400. Over the next 500 years, there will be no leap day in 2100, 2200, 2300 and 2500.

There will be leap days in 2028, 2032 and 2036.

Without a leap day, farmers might have trouble planting in the correct season, Khan said. "Christmas would be in summer. There will be no snow. There will be no feeling of Christmas," he said.

You might wonder who came up with the idea of leap day. Experts say the calendar change developed over time.

Ancient civilizations planned their years based on either the moon or the sun. By the time Julius Caesar controlled the Roman Empire, things had gotten more complicated. People had written down the calendars but seasons were "drifting." For example, the weather in July was not always the same. So in that time, they added months to the calendar. But that did not really fix the problem.

The Romans fixed³ the problem in the year 46 BCE. The year became 365-and-one-fourth days long. So an extra day was added every four years. The Romans came close, but a year is actually 365 plus 0.242 days, says Nick Eakes, an astronomy⁴ professor at the University of North Carolina in Chapel⁵ Hill.

There have been multiple calendars used by western societies. The Athenian and the Julian calendars were used thousands of years ago. The Athenian calendar, however, ran into problems when holidays were not falling in the correct seasons, said Thomas Palaima, a classics professor at the University of Texas at Austin.

Over time, the current calendar also changed because of holidays. The leader of the Roman Catholic⁶ Church, Gregory XIII, fixed the calendar again in the late 1500s. He wanted to be sure the Christian⁷ holiday of Easter happened in early spring. So Gregory and his advisors⁸ did the difficult math to come up with something very close to the calendar we use today.

"If the solar year was a perfect 365.25 then we wouldn't have to worry about the tricky⁹ math involved," said Eakes, the astronomy professor.

Special birthdays

After the calendar, the main concern for leap day centers on those born on that day, February 29. It only comes around once every four years (for the most part.)

It is a conversation starter for many. It can be an administrative¹⁰ headache – some people must fill out official documents and say their birthday is either February 28 or March 1. Some computer systems have not yet been updated to include February 29 as a choice.

Only about 5 million of the 8 billion people worldwide were born on February 29. Shelly Dean¹¹ of Seattle, Washington is one of them. Growing up, she said, she had normal birthday parties each year, but every fourth year, she had a special party.

She is now 23, but has not had too many "special" birthdays. So this year, she is planning one. She missed celebrating with her family four years ago, because she was attending school in New York. So on Thursday, she gets to celebrate her special day for the first time in eight years with her family.

"It's a very big day," she said.

Words in This Story

calendar –n. a document, chart, etc., that shows the days, weeks, and months of a year

equinox –n. a day in the year where there is an equal amount of sunlight and darkness

solstice –n. the longest day of the year

classics –n. a study area that includes material that has been looked at for hundreds of years

drift –v. to move slowly but not with a clear direction

1 lengthen   

vt.使伸长，延长

参考例句：

• He asked the tailor to lengthen his coat.他请裁缝把他的外衣放长些。
• The teacher told her to lengthen her paper out.老师让她把论文加长。

2 instructor   

n.指导者，教员，教练

参考例句：

• The college jumped him from instructor to full professor.大学突然把他从讲师提升为正教授。
• The skiing instructor was a tall,sunburnt man.滑雪教练是一个高高个子晒得黑黑的男子。

3 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

4 astronomy   

n.天文学

参考例句：

• Mathematics is connected with astronomy.数学与天文学有联系。
• Astronomy is an abstract subject.天文学是一门深奥的学科。

5 chapel   

n.小教堂，殡仪馆

参考例句：

• The nimble hero,skipped into a chapel that stood near.敏捷的英雄跳进近旁的一座小教堂里。
• She was on the peak that Sunday afternoon when she played in chapel.那个星期天的下午，她在小教堂的演出，可以说是登峰造极。

6 catholic   

adj.天主教的；n.天主教徒

参考例句：

• The Pope is the supreme leader of the Roman Catholic Church.教皇是罗马天主教的最高领袖。
• She was a devoutly Catholic.她是一个虔诚地天主教徒。

7 Christian   

adj.基督教徒的；n.基督教徒

参考例句：

• They always addressed each other by their Christian name.他们总是以教名互相称呼。
• His mother is a sincere Christian.他母亲是个虔诚的基督教徒。

8 advisors   

n.顾问，劝告者( advisor的名词复数 )；（指导大学新生学科问题等的）指导教授

参考例句：

• The governors felt that they were being strung along by their advisors. 地方长官感到他们一直在受顾问们的愚弄。 来自《现代汉英综合大词典》
• We will consult together with advisors about her education. 我们将一起和专家商议她的教育事宜。 来自互联网

9 tricky   

adj.狡猾的，奸诈的；(工作等)棘手的，微妙的

参考例句：

• I'm in a rather tricky position.Can you help me out?我的处境很棘手，你能帮我吗？
• He avoided this tricky question and talked in generalities.他回避了这个非常微妙的问题，只做了个笼统的表述。

10 administrative   

adj.行政的，管理的

参考例句：

• The administrative burden must be lifted from local government.必须解除地方政府的行政负担。
• He regarded all these administrative details as beneath his notice.他认为行政管理上的这些琐事都不值一顾。

11 Dean   

n.(大学)院长，系主任，教务长

参考例句：

• The students much like the new dean.学生们很喜欢这位新系主任。
• Who is the dean of the Foreign Languages Department?外语系主任是谁？