31May

what-if:塔图因的彩虹

时间: 2016-5-31 分类: 涨姿势拓视野 作者: XD

TAGS: ,

语言:   大陆 港澳 台湾

引用元:http://what-if.xkcd.com/150/


 

Tatooine Rainbow

塔图因的彩虹

 

what-if:塔图因的彩虹

 

Since rainbows are caused by the refraction of the sunlight by tiny droplets of rainwater, what would rainbow look like on Earth if we had two suns like Tatooine?

—Raga

我们知道彩虹是由于微小的雨滴折射太阳光造成的,那么如果我们像塔图因一样拥有两颗太阳的话,地球上的彩虹应该是什么样的?

—拉格

 

A planet with double suns would have double rainbows.

一颗拥有两颗太阳的星球就会有双重彩虹。

Or rather, quadruple rainbows. Our rainbows here on Earth are already double rainbows—there’s a second, fainter bow above the main one. You can’t always see this second rainbow, since the clouds need to be just right, so people get excited when they see one.

或者说,会有四重彩虹,应为地球上的彩虹已经是双重的了,微弱的第二道彩虹(霓)存在于第一道彩虹(虹)之上。除非云层的光影正好,不然你是看不到第二道彩虹的,所以当人们看到两道彩虹时会相当的兴奋。

what-if:塔图因的彩虹

Vowing not to reference that video any further anywhere in this article, on principle.

我发誓,原则上,我不在这篇文章中引用那个视频

The area between the two rainbows is darker than the area outside because raindrops reflect light more strongly in certain directions. That region has a name, by the way—it’s called Alexander’s dark band.

两道彩虹之间的区域会比外侧的区域更暗,因为雨滴会将光反射到某一特定方向。这一区域我们称之为亚历山大暗带。

what-if:塔图因的彩虹

‘GET OFF THE STAGE!’ ‘AND RETHINK YOUR LIVES!’

‘滚下舞台!’‘给我重新思考你们的人生!’(原曲应该是Over the Ringbow)

The first and second rainbows are the only ones you can see easily, but there are actually many more bows beyond those two, each one fainter than the last. Rainbows are formed by light bouncing around in raindrops, and the different bows are formed by different paths the light can take. The main rainbow is formed by the most common paths through the droplet, and other paths—where some of the light bounces around in more unusual ways—make the fainter second, third, fourth, and even fifth rainbows.

霓和虹是比较容易观察到的彩虹,但是事实上,除了这两道彩虹,还有许多道彩虹,他们每一道都比前一道更加暗淡,彩虹是光在雨滴里折射反射形成的,不同的光路形成了不同的彩虹,虹的路径是光在雨滴里通过的最主要的路径,一部分光会在雨滴里多次反射,形成其他路径,从而造成了更暗的第二,第三,第四甚至第五道彩虹。

 

what-if:塔图因的彩虹

There are higher-order rainbows, too. Really, we all live in a rainbow tube.

这里还有更高阶的彩虹。事实上我们都生活在彩虹管里。

Usually, only the first and second rainbows are bright enough to see; it was only in the last five years that anyone took pictures of the third, fourth, and fifth rainbows.

通常情况下,只有霓和虹是亮到能够看见的,只有在最近五年中,有人拍摄到过第三,第四,第五道彩虹

Rainbows appear on the other side of the sky from the Sun, so to figure out what a double rainbow would look like on a planet with two suns, we need to figure out where the suns usually appear in the sky on that kind of planet.

彩虹只会出现在太阳的对面,所以要想知道拥有两颗太阳的行星上的彩虹的样子,我们首先要弄清楚这颗星球上天空中的太阳是什么样的。

There are planets with two suns out there, although we didn’t know that for sure until recently. Double-star planets come in two main varieties:

直到最近,我们才确定拥有两颗太阳的星球是存在的。双星星球主要有以下两种情况:

what-if:塔图因的彩虹

[actual size]

实际大小

In the first kind of system, the two stars are close together and the planet goes around them far away. This kind of planet is called a circumbinary planet. In the second kind of system, the two stars are farther apart, and the planet orbits one of them[1] while the other stays far away. This kind of planet is called [the other kind of planet].[2]

第一种系统中,两颗恒星彼此靠近,行星围绕着他们公转。这种星球我们称为环联星行星。第二种系统中,两颗恒星都相隔较远,行星围绕着他们[1]当中的一个公转,这种星球我们称为[其他种类行星][2]。

If you lived on [the other kind of planet],[3] the two Suns would spend most of the year in different parts of the sky. Depending on how big they were, they may also be very different in brightness. If you were orbiting the larger star, the smaller one might be no brighter than the Moon,[4] or even look like an ordinary planet or star.

如果你住在[其他种类行星][3]上面,一年当中的大部分时间,这两颗太阳会在天空中不同的地方。根据他们的大小情况,他们也许有不同的亮度。如果这颗星球围绕大的恒星公转,那颗小的恒星或许跟月亮[4]差不多亮,甚至像一颗普通的行星或星星。

Tatooine, in Star Wars, looks like it’s probably a circumbinary planet. The two stars appear pretty close together in the sky and similar in color and size, so it seems reasonable to guess they’re actually near one another, with Tatooine orbiting both of them. Two suns would create two overlapping rainbows. The main bow of the rainbow is a circle about 84 degrees across, centered in the sky exactly opposite the Sun.[5] The farther apart the two suns were, the farther apart the rainbows would be. If the two suns were 84 degrees apart, the main bows of the two rainbows would barely touch.

星球大战里的塔图因看起来像是一颗环联星行星,因为两颗颜色和大小差不多的太阳在天空的位置很靠近,所以有理由相信他们是一个双星系统,塔图因围绕着他们公转。两颗太阳会产生两道重叠的彩虹,他们会出现在与太阳相对的天空中,虹的形状大概是两道跨度达到84度的弧。两颗太阳相距越远,两道彩虹错开的距离也就越大,如果两颗太阳错开距离达到84度,那么这两道彩虹的虹可能正好相接。

A pair of suns 84 degrees apart would be possible around [the other kind of planet], but not around Tatooine-type[6] circumbinary planets. The reason is simple: A planet orbiting two stars can’t get too close to them or its orbit becomes unstable. If it gets too close, the irregular tugging from the gravity of the two stars as they orbit will eventually cause the planet to crash into one of them or get flung out of the system.

在[其他种类行星]上,两颗太阳也许能够达到84度的间隔,但是在塔图因型[6]的环联星行星上却不行。原因很简单:行星围绕恒星公转的轨道不能靠恒星太近,否则它的轨道将变得不稳定。如果行星轨道太靠近恒星,两颗恒星不规则的引力会造成行星与某颗恒星相撞,或者被甩出双星系统。

For a system with two similar-sized stars, this “critical radius” is around six times the distance between the two stars.[7] This means that the two suns would never get more than about 20 degrees apart in the sky:

对于两颗有着相同大小的双星系统,这个“临界半径”大概是两颗恒星间隔的六倍,这意味着,两颗太阳在天空中的距离不会超过20度。

what-if:塔图因的彩虹

tan-1(a) = ta

tan-1(a) = ta(shenmegui,哪有这样的三角函数)

This tells us that the two rainbows in a Tatooine-like system would always overlap.[8] The colors would blend together where the bows crossed, and the dark bands would too.

因此,塔图因型星上的两道彩虹总是重叠的[8]。彩虹重叠时,颜色和暗带也会重叠。

I suppose doubling all the rainbows would also double the number of pots of gold at the end of each rainbow.[9] And it’s not just pots of gold; I guess we’d need to rethink all kinds of rainbow references.

我假设彩虹数量加倍,彩虹尽头埋的黄金数量也会加倍[9]。其实不仅仅是黄金数量,我想彩虹的所有参数都要重新考虑了。

(彩虹尽头有黄金是爱尔兰的传说,形容永远得不到的报酬,或可望不可及的财富。)

Overlapping rainbows would be beautiful, but definitely a lot more complicated.

叠加的彩虹固然美,但是绝对要复杂多了。

what-if:塔图因的彩虹

At least it’s not as ambiguous as ‘second star to the right.’

至少不像‘右手边第二颗星’那样模棱两可。(Second Star to the Right也是首歌吗?)

 


[1] Not necessarily the bigger one.

[1]不一定是大的那个。

 

[2] I’m sorry, I’ve just never learned a good word for these.

[2]对不起,我不知道这种情况应该叫什么。

 

[3] Sorry.

[3]再次抱歉。

 

[4] Which would still be bright enough to cast a rainbow!

[4]这个亮度依然有可能造成一次彩虹。

 

[5] This is why you never see more than half of a rainbow above the horizon. If the center of the rainbow were above the horizon, it would mean the Sun was below it behind you, so there wouldn’t be sunlight to make a rainbow in the first place.

[5]这就是为什么你在地面上只能看到一半彩虹。如果彩虹的圆心在地面之上,这意味着太阳的位置比你还低,而在这个位置上,你是看不到阳光的,更别说彩虹了。(坐在飞机上就有可能看到圆形的彩虹哦。)

 

[6] If Star Wars had just used the other kind of planet, we could use its name for them and solve this problem.

[6]如果星球大战的塔图因是“其他种类行星”那样的星球,我们就可以用这个名字来代替“其他种类行星”,这样问题就解决了。

 

[7] This is a very rough number; it can range from four to eight depending on the exact arrangement. We’ve found a lot of planets close to thatcritical radius, which suggests that maybe they slowly migrate inward until they reach it and are ejected or destroyed. Strangely, we haven’t found many big Jupiter-sized planets around binary stars in general; we should be seeing them if they’re there, so the lack of them is a mystery.

[7]这是个很不精确的估计值,根据具体的双星系统的状态,这个值会在4-8之间变动。我们找到很多接近“临界半径”的星球,这说明双星系统里的行星轨道会慢慢的向内收缩,直到“临界半径”,然后被甩出星系或者被毁灭。奇怪的是,我们发现双星系统中像木星大小的行星很少见,如果他们存在,我们就应该能够观察到,但现在看不到,为什么出现这种情况对我们来说还是一个谜。

 

[8] Assuming the raindrops are made of water, or something with similar refractive properties.

[8]假设这里的雨滴还是由水构成,或者是由和水差不多折射率的物质构成。

 

[9] Come to think of it, do our rainbows have one pot of gold or two? I’ve never really thought about it.

[9]细想起来,彩虹尽头埋的黄金是只有一头埋了还是两头都埋了?我还真没仔细想过这个问题。

 


XD:不知不觉就150回了,然而和我并没有什么关系


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Comments
已有 8 条评论 新浪微博
  1. MiyanokoMizuho

    前几天看的双彩虹 虹&霓

    2016年6月1日 14:56 回复
  2. 777

    嘿~完全看不懂

    2016年6月1日 03:08来自移动端 回复
  3. TC

    Vowing not to reference that video any further anywhere in this article, on principle.
    这里的视频指的是这个
    https://www.youtube.com/watch?v=OQSNhk5ICTI
    还有一个音乐版的
    https://www.youtube.com/watch?v=MX0D4oZwCsA

    2016年5月31日 13:221 回复
    • XD

      感谢指出,这里翻译的时候感觉是在说什么视频,我还在想是不是那个彩虹猫呢

      2016年5月31日 15:191 回复
      • 匿名

        彩虹猫 23333333

        2016年6月1日 18:221 回复
    • Swanfal

      对对对 Youtube早年超火的23333

      2016年6月4日 13:56 回复
  4. 脑残粉

    想起one piece的圆形彩虹

    2016年5月31日 12:28来自移动端 回复
  5. CyclizePei

    interesting

    2016年5月31日 12:05来自移动端 回复
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