What creates a total solar eclipse? - Andy Cohen

日全食是如何产生的? -安迪·科恩

翻译人员: sherry lee 校对人员: Jian Zhipeng

On August 21, 2017

在2017年8月21日

the shadow of the Moon will pass

当月球的阴影开始从

from the west coast to the east coast of the U.S.

美国西岸移动到东岸的时候

Our blue sky will turn black as night

我们的白天就会变得像黑夜一样

并有漫天繁星相随

and fill with stars,

and there will be a hole in the sky

天空中会有一个空出来的洞

where the Sun used to be,

那是太阳所在的位置

surrounded by the fiery ring of the Sun's corona,

外面有一层火焰般的环状物，也就是日冕

a total eclipse of the Sun.

日全食的发生

This will truly be a historic event.

将会富有历史意义

Accounts of solar eclipses

对日蚀的记录一直存在

date way back on the written record.

最早的记录可以追溯到

The early Mesopotamians wrote

古老的美索不达米亚人所写下的壮观景象

that the Sun was put to shame

那是在公元前14世纪,

during the solar eclipse of the 14th century B.C.E.

当时他们认为日蚀是种耻辱的象征

and it may have started

这也许也开始让

the Sun worship of the Egyptian pharaoh Akhenaten.

埃及法老阿肯那顿信奉太阳的神明

Ancient Chinese astrologers paid with their lives

古代中国的占星师

if they failed to predict the solar eclipse

如果没能准确预报日蚀现象

and portend the fate of their emperors

和预言皇帝的运势将会丢掉性命

而他们的皇帝就是太阳的象征

whose symbol was the Sun.

The earliest date of a specific event in human history,

历史上最早记录的一次特殊事件

是吕底亚人和米迪亚人之间的一场战争

a battle between the armies of Lydia and Media,

occurred on May 28, 535 B.C.E.

它发生在公元前525年5月28日

when a solar eclipse caused the soldiers

当时发生的日蚀现象使士兵们

to lay down their arms and declare a truce.

都放下武器，宣布停战

So how does it happen?

而日食现象到底是如何产生的？

During a total solar eclipse,

在发生日全食的时候

the Moon moves between the Earth and the Sun.

月球移动到了地球和太阳之间

When this happens, the disc of the Moon

这时，月球的身影

appears to perfectly cover the disc of the Sun

会完全掩盖住太阳

even though the Sun is much larger than the Moon.

虽然太阳体型远远比月球大得多

But how is this possible?

但这真的可能吗？

The Sun is 400 times bigger than the Moon,

太阳的体积比月球大400倍

but by sheer coincidence,

不过碰巧的是

the Moon is 390 times closer to Earth.

月球离地球的距离比太阳近390倍

Size and distance cancel each other out

两者体积上和与地球距离的差距会相互抵消

so that the Moon and Sun appear

使月球和太阳看上去

to be almost the exactly same size.

几乎一样大

Every time the Moon orbits the Earth,

每次月球绕地球转的时候

once every 27.3 days,

都要花上27.3天

it has to pass between the Earth and the Sun,

它都要穿过地球与太阳之间

a stage called the new moon phase.

这个阶段叫做新月

And every time it passes,

而每次月球经过的时候

the New Moon has a chance to block out the Sun.

新月都有可能挡住太阳

Most of the time,

而大部分时候

the Moon passes a little above

月亮都只挡住太阳上部

or a little below the Sun,

或下部小部分区域

but if they align perfectly,

但如果两者完全重叠

the shadow of the Moon

月球的阴影

will make a narrow path across Earth

就会完全挡住太阳光对地球的照射

and those in the shadows will see a total solar eclipse.

而所呈现出的阴影就成为了日全食

Just like on night side of the Earth,

就像进入黑夜的地球一样

the sky during a total eclipse is black

日全食时的天空是全黑的

and filled with stars.

充满繁星

But while the moon perfectly covers

但如果月球完全遮盖

the surface of the Sun,

太阳的表面的时候

it doesn't block out the Sun's outer atmosphere,

它并没有盖住太阳的外部大气层

its corona, which appears as a fiery ring

也就是日冕，它看上去有如火焰般的外环

around the dark disc of the moon.

笼罩在黑暗的月球周围

Solar eclipses occur several times a year,

日食每年都会发生几次

but most often they are partial eclipses

但大部分都是日偏食

where the Moon doesn't quite line up with the Sun.

月球并没有完全与太阳重叠

And, when the Moon and Sun are perfectly aligned,

而当月球完全与太阳重合的时候

the Moon is usually too far from Earth in its orbit

月球通常会与地球离得太远

to completely cover the Sun,

无法完全遮住太阳

creating an annular eclipse.

这就变成了日环食

During an annular or partial eclipse,

在日环食或日偏食发生时

the sky remains bright.

天空仍然是亮的

Even on those rare occasions of a total eclipse,

即使是在罕见的日全食时

the Moon's shadow is most likely to fall

月球的阴影很有可能

on the 70% of Earth that is covered by water,

会投到海面

and few people, if any, will see it.

只有极少数人能看到

The eclipse of 2017 will be remarkable on a larger scale

发生在2017年的日食会是规模很大的一次

because the Moon is slowly moving away from Earth.

因为月球远离地球的速度很慢

If a furry ancestor of ours had bothered to look up

如果我们的祖先

during a solar eclipse a hundred million years ago,

在一亿年前的日全食时曾抬头看看天空

it wouldn't have seen the fiery corona of the Sun.

他们也许不会看到太阳外层的日冕

It would have just been dark.

只看到一片漆黑

Eventually, the Moon will have moved too far from Earth

最终，月球会远离地球至一定程度

to completely cover the disc of the Sun.

至完全遮盖太阳

It is only during our little wink of Earth's history

这个过程对地球的漫长历史来说只不过是眨眼之间的事

that the Moon is at just the right distance

这不过是月球刚好处在离地球合适的位置

to cause a total solar eclipse

形成了日全食

yet not block the Sun's corona.

并使日冕露出来

So on August 21, 2017,

所以在2017年8月21日

when the Moon exactly lines up with the Sun

当月球完全与太阳重叠

and the Moon is close enough to the Earth,

而与地球距离正好的时候

its shadow will cross the U.S.

它的阴影会穿越美国

and, if you happen to be in its narrow path,

如果你刚好与三者位于同一条直线时

you will witness one of the most

你将会目击到

awe-inspiring sights in the universe.

宇宙中最为雄伟壮观的景色

But, as incredible as this event will be,

但是，伴随其壮观景色的是

total eclipses are one of the most dangerous as well.

极大的危害

Only specially tinted filters,

只有使用特质的

specifically designed to observe the Sun,

专门用来观察日食的过滤眼镜

should be used.

可以用来观看日食

The eclipse might put the Sun to shame,

日食现象也许会有损太阳的尊严

but even a shamed Sun

但即使是有失尊严的太阳

can seriously damage your eyes.

也会刺伤你的眼睛