11月19日，将发生本世纪时长最长的月偏食。月球将在地球的阴影中滑动3小时28分钟，在全球许多地方可观看这一天文现象。据预测，月亮直径的97.8%都会进入地影，非常接近月全食。届时月亮将几乎完全呈红色，类似于去年五月看到的“血月”。
The longest lunar eclipse this century will happen early Friday morning. Here's how to see it.
The longest lunar eclipse of this century is coming this week.
本世纪时间最长的月偏食将在本周到来。
On Friday, Earth will pass between the sun and moon, casting a shadow over the latter. The eclipse will peak just after 4 a.m. Eastern Time, when our planet will hide 97% of the full moon from the sun's light, giving the moon a reddish hue.
本周五，地球将在太阳和月亮之间经过，并在月球上投下阴影。月偏食将在美国东部时间凌晨 4 点之后达到顶峰，届时我们的星球将把 97% 的满月从太阳光中隐藏起来，使月亮呈现微红色。
According to NASA, the partial lunar eclipse will last 3 hours, 28 minutes, and 23 seconds — longer than any other eclipse between 2001 and 2100.
据美国宇航局称，月偏食将持续 3 小时 28 分 23 秒——比 2001 年至 2100 年间的任何其他月食都要长。
For the upcoming eclipse, sky watchers in North America have the best seats in the house. People in all 50 US states, Canada, and Mexico can watch the full event.
对于即将到来的月偏食，北美的天文爱好者拥有最好的观测地点。美国所有 50 个州、加拿大和墨西哥的人们都可以观测到完整的月偏食过程。
You won't need a telescope or binoculars — simply go outside and look up at the sky any time between 2:19 a.m. and 5:47 a.m Eastern Time on Friday.
人们不需要望远镜，只需在美国东部时间周五凌晨 2 点 19 分到 5 点 47 分之间的任何时间抬头仰望天空便可看到。
Folks in South America and western Europe will see most of the eclipse, though the moon will set before it ends. People in western Asia and Oceania will miss the earlier part of the event, as the moon will not have risen yet. Those living in Africa and the Middle East won't see any of the spectacle.
南美洲和西欧的人们将看到大部分月偏食，尽管月亮会在月偏食结束之前落下。西亚和大洋洲的人们将错过月偏食刚开始的部分，因为月亮尚未升起。那些生活在非洲和中东的人则与此次月偏食无缘。
After centuries of complete lunar eclipses, the Lunar Saros cycle is moving into a series of partial lunar eclipses. The lunar eclipse on November 19, 2021 will be the longest lunar eclipse in nearly 600 years. The partial blackout on November 30, 2039 is only 2 minutes shorter.
在经历了几个世纪的月全食之后，月球沙罗周期将迎来一系列月偏食。 2021年11月19日的月食将是近600年来持续时间最长的月偏食。 2039 年 11 月 30 日的月偏食仅缩短了 2 分钟。
A longer partial eclipse will not take place until February 8, 2669.
时间更长的月偏食要到 2669 年 2 月 8 日才会发生。
How a lunar eclipse works — and why it turns the moon red
为何会发生月食——以及月亮为何会变成红色
Typically, the moon's white-grey face is illuminated by sunlight reflecting off its surface. But during a lunar eclipse, the moon, sun, and Earth briefly align so that our planet blocks sunlight from reaching the moon.
通常，月亮的白灰色面被从其表面反射的阳光照亮。但是在月食期间，月球、太阳和地球会短暂连成一条直线，而地球挡住了阳光到达月球。
A total lunar eclipse occurs when 100% of the moon is obscured by the Earth's cone-shaped shadow, known as the umbra. During a total eclipse, or near-total eclipse like this month's event, the lunar surface takes on a bloody visage.
当月球 100% 被地球的锥形阴影（称为本影）遮挡时，就会发生月全食。在月全食或类似本次接近月全食的月偏食期间，月球表面呈现出血红的颜色。
We have oxygen and nitrogen particles in Earth's atmosphere to thank for that light show. They're better at scattering certain shorter wavelengths of light, like blue or violet, so colors with longer wavelengths — like red, orange, or yellow — still linger. When the moon sits in Earth's shadow, those reddish colors dominate what you see.
我们在地球大气层中有氧和氮的微小粒子，它们将某些较短波长的光（例如蓝色或紫色）散射掉了，因此波长较长的光（例如红色、橙色或黄色）仍然存在。当月亮位于地球的阴影中时，你所看到的月球将呈现出这种红色。
