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日食

Solar Eclipse 101 | National Geographic

A solar eclipse happens
日食之所以发生
when a new moon moves between the Earth and the sun,
是因为朔月运行到了地球和太阳的中间
blocking some or all of the sun’s rays from reaching the Earth.
阻挡了投射到地球的部分或全部的太阳光线
By cosmic chance, even though the sun is 400 times wider than the moon,
由于宇宙巧合 虽然太阳的直径是月球的四百倍
it’s also 400 times farther away.
但它到地球的距离也是月球的四百倍
Therefore, the two objects appear the same size in our sky.
因此 太阳和月球在我们看来同样大小
Astronomers are able to predict eclipses
天文学家能够预测日食
because the Earth and moon have very predictable orbits.
是由于地球和月球的轨道是颇为确定的
Why, then, isn’t there an eclipse every month?
那为什么不是每个月都有日食呢?
The moon’s orbit is usually tilted
月球的轨道相对于地球
a few degrees north or south in relation to the Earth.
通常是向北或向南倾斜几度
When the moon does eclipse the sun,
当月球遮挡住太阳时
it casts two types of shadows on Earth:
它会在地球上投下两种阴影
a smaller, darker shadow, known as the umbra,
一种更小 更暗的阴影 称为本影
and a larger shadow, known as the penumbra.
另一种更大的阴影 称为半影
There are four types of solar eclipses.
日食有四种类型
The first and most spectacular is a total eclipse,
第一种也是最壮观的一种就是日全食
when the moon completely covers the sun’s surface.
即月球完全遮挡了太阳表面
A total eclipse can only be seen
只有当你站在本影范围内
if you’re standing within the umbral shadow.
才能看见日全食
That’s why the imaginary line created by this shadow
这就是为什么本影在地球上移动时
as it races across Earth is known as the path of totality.
所形成的假想线被称为全食带
People within the penumbral shadow
当你位于半影范围内
see only a partial eclipse, the second type.
就只能看见日偏食 这就是第二种
From this view, outside the path of totality,
在这个位置 全食带以外
the moon passes in front of the sun off-center,
月球在太阳前面偏离中心经过
never fully covering its surface.
从未完全遮挡它的表面
Third, an annular eclipse,
第三种 日环食
occurs when the moon passes directly in front of the sun.
发生在月球直接经过太阳前面时
However, unlike a total eclipse,
但是 和日全食不同
the moon appears too small to fully cover the sun.
月球显得太小而不能完全遮挡住太阳
The moon’s orbit is elliptical,
月球轨道是椭圆的
so sometimes it’s closer to Earth
所以有时它离地球近
and sometimes it’s farther away.
有时离地球远
Last, a hybrid eclipse,
最后一种 混合食
is when the moon’s position between the Earth and sun is so finely balanced
是指月球在地球和太阳之间处于微妙的平衡位置
that the curvature of the Earth plays a role.
地球的曲率在其中起到了一定的作用
The moon will be farther away from some parts of Earth along the eclipse’s path,
沿着日食带 有些地区离月球较远
resulting in an annular eclipse.
从而产生了日环食
In other parts, the moon will be just close enough
而其他地区 月球刚好足够近
to fully cover the sun, resulting in a total eclipse.
能够完全遮挡太阳 从而产生日全食
While a total solar eclipse happens
虽然地球上的某些地方
somewhere on Earth every year or two,
每一两年就会出现一次日全食
any given point on Earth experiences the event
但地球上任何一个特定的地点
only about once every 400 years.
大约每四百年才会经历一次
(high-pitched hum) (static crackles)
[高音调的嗡嗡声][静电爆裂声]
We interrupt this video
由于一个重要的安全通知
for an important safety announcement.
我们中断了视频
Looking directly at the sun,
即使在日食期间
even during an eclipse, can cause permanent eye damage.
直视太阳也会造成眼睛的永久性损伤
Fortunately, there are ways to enjoy an eclipse safely.
幸运的是 有一些方法可以安全地观看日食
The easiest is to use certified eclipse-watching glasses,
最简单的就是使用经过认证的日食观察眼镜
which are shaded thousands of times darker than typical sunglasses.
它的比普通太阳镜要暗几千倍
You can also look at the eclipse indirectly
你还可以制作一个针孔查看器
by making a pinhole viewer.
来间接地观察日食
Simply poke a small hole in a piece of cardboard.
只需要在一张纸板上戳一个小洞
Hold the cardboard up to the sun,
把纸板对着太阳
allowing the sun’s image to be projected onto a flat surface.
让太阳的影像投射到一个平面上
Be sure to look only at the surface and not through the cardboard.
记住只能看平面 不要通过纸板看太阳
Just before the moon completely covers the sun,
在月球完全遮挡太阳之前
low-lying valleys on the moon’s edge will be the only spots that sunlight continues to pass through.
太阳光只能通过月球边缘的低洼山谷穿过
These remaining brilliant shafts of light,
这些被称为贝利珠的残余亮光
known as Baily’s beads, will disappear one after another.
将一个接一个消失
And finally, a single bead of light remains, known as the Diamond Ring,
最后剩下的那颗光珠 被称为钻石环
signaling that you’re just seconds away
这表明你离观看日全食
from experiencing totality.
只有几秒钟的时间了
Once the last bead disappears
一旦最后一颗珠子消失了
and the moon completely covers the sun’s surface,
月球完全遮挡了太阳表面
the view through your eclipse glasses will be pitch black.
你通过日食眼镜看到的将是一片漆黑
Totality achieved.
这就是日全食了
At this point, none of the sun’s rays are reaching your eyes
这时 没有太阳光会照射到你的眼睛
and it’s the only time that it’s safe to take off your glasses.
只有在这个时候 拿下眼镜是安全的
Remember to put your eclipse glasses back on
记住在太阳光再次出现前
before any of the sun’s rays start to peek through again.
戴上你的日食眼镜
Any sunlight reaching your eyes, even for a few seconds,
任何照射到你眼睛的太阳光
can cause serious damage.
即使只有几秒钟 也会造成严重的伤害
While an eclipse can last a few hours,
虽然日食可以持续几个小时
totality typically occurs for less than three minutes.
但日全食通常只持续不到三分钟
Animals and plants have also been known
动物和植物也会在日全食时
to alter their behavior during a total eclipse.
改变它们的行为
Songbirds may stop singing, crickets may start chirping,
鸟儿可能会停止歌唱 蟋蟀可能会停止鸣叫
and flowers might even start to close up.
花朵甚至可能会开始闭合
We won’t always be able to see total solar eclipses.
我们不是总能看到日全食
The moon moves about one and a half inches away from Earth each year.
月球一直在以每年1.5英寸的速度远离地球
It’s estimated that in about a billion years,
据估计 在大约十亿年后
the moon will be too far away from Earth
月球将会由于距离地球太远
to completely cover the sun.
而不能完全遮挡太阳

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视频概述

你知道日食是如何发生的吗?当你有幸遇到日食,又该如何安全地观看呢?这里将告诉你所有答案!

听录译者

收集自网络

翻译译者

神经蛙

审核员

审核员LJ

视频来源

https://www.youtube.com/watch?v=cxrLRbkOwKs

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