Can you solve the dark matter fuel riddle? - Dan Finkel

翻译人员: Carol Wang 校对人员: Candace Hwang

It’s an incredible discovery:

这是个惊人的发现：

an ancient, abandoned alien space station filled with precursor technology.

一个古老、遭遗弃的外星人空间站， 里面装满了先驱的科技。

But now, every species in the galaxy is in a mad dash to get there first

可眼下，银河系所有物种 都疯狂的冲向空间站，

and claim it for themselves.

想第一个抵达，并抢占它。

And right away, you’ve got a problem.

而你马上就碰到问题了，

Your ship’s faster-than-light jump drive consumes 1 unit of fuel

你的飞船使用了超光速跳跃引擎，

for every parsec of distance it takes you,

每行驶一个秒差距的距离， 就消耗1个单位的燃料，

and your ship holds only 15 units of fuel.

但仅能容纳 15 个单位的燃料。

But the space station is 23 parsecs away,

而空间站离你有 23 个秒差距，

and there’s only empty space between there and here.

而且沿途空无一物。

There’s one thing that can help you, though:

然而，有一样东西能帮到你：

dark matter fuel is stable in deep space.

暗物质燃料在深空中是稳定的。

That means you can vent a cache of it from your fuel chamber,

即可从燃料箱里排出一批燃料，

and then come back to pick it up again later.

稍后再回来取走。

Even though your ship holds only 15 units of fuel,

尽管船仅可容纳 15 个单位燃料，

you’ve been granted use of all 45 units in your current location.

但你已获准使用当前位置 全部45个单位燃料。

With some strategic fuel caching along the way,

只要沿途合理布置燃料缓存，

you might be able to make it all 23 parsecs.

你就有可能完成 23 个秒差距。

So how can you reach the alien space station?

那么，如何才能到 达外星人空间站呢？

[若想自己解答，可暂停视频]

Answer in 3,

[答案倒计时：3 秒]

2,

[ 2 秒]

1.

[ 1 秒]

It’s possible to solve this riddle using as few as two cache points,

至少需要两个缓存点才能解开谜题，

and there are also valid solutions that use more.

也有设置更多缓存点的有效方案。

No matter how you go about it though,

不管你如何去做，

the key is determining exactly where to cache fuel along your route.

关键是如何确定途中 缓存燃料的准确位置。

Let’s work backwards from the alien space station.

我们就从外星人空间站开始倒推吧。

To reach 23 parsecs,

要完成 23 个秒差距的距离，

you’ll have to leave the 8-parsec mark with a full tank of fuel.

那么在 8 个秒差距的位置， 你必须有一整箱燃料。

The 8-parsec point is too far from the start to use as a cache right away;

但 8 个秒差距的位置离起点太远， 无法用作缓存点;

you could jump there, but wouldn’t have enough fuel to return to the start,

你能行驶到那里， 但燃料不足以返回到起点，

let alone store any for later.

更别提为以后储存燃料了。

So that means you’ll need to find a cache somewhere between the start and 8.

因此，必须在起点 和 8 个秒差距间找一个缓存点。

But where?

但是，选哪呢？

There’s an interesting pattern that can help.

一个有趣的模式可能有用。

At the start you have exactly 3 tanks’ worth of fuel.

在起点位置，你有 3 箱燃料，

At 8 parsecs you need exactly 1.

在 8 个秒差距位置， 你只需要 1 箱燃料。

Is there a point, which we can call point X, where you could have exactly 2?

可否在点 X 位置存 2 箱燃料呢？

That would be useful, because then you could refuel there exactly twice,

这可能很有用，因为 你可在 X 处加 2 次燃料，

making full use of your storage capacity without any waste.

从而充分利用燃料储备 而没有任何浪费。

Wherever point X is,

不论点 X 设在哪里，

you’ll jump forward from it twice:

你会去那里两次：

once to deposit some fuel at the 8-parsec cache point, and a second time for good.

一次是在 8 秒差距缓存燃料， 第二次是取走后不再回来。

So you’ll jump the distance between X and 8-parsecs 3 times in all.

所以在点 X 和 8 秒差距间 你一共飞行 3 次，

You’d have 2 tanks of fuel at point X, and need 1 left at the 8 parsec cache point,

你有 2 箱燃料放在点 X ， 8 个秒差距缓存处需留 1 箱燃料，

so you can spend one tank-- or 15 units-- going back and forth.

因此，你在这两点之间来回 3 趟 可用 1 箱燃料——即 15 单位燃料，

Since 15 units divided by 3 trips is 5,

15 (单位燃料) 除以 3 (趟)等于 5，

we can place these two cache points 5 parsecs apart.

即两个缓存点的距离为5个秒差距，

Any farther, and you wouldn’t have enough fuel to reach the alien space station.

距离再大一点点的话，你将 没有足够燃料到达外星人空间站。

So it looks like the earliest we can place point X is at the 3-parsec mark.

因此，点 X 最近可设在 3 秒差距处。

Is it possible to transport 30 units of fuel there? Let’s try.

能将 30 单位燃料运到 X 处吗？ 一起试试看。

You set out with a full tank of 15 units.

你出发满载 15 单位燃料，

You jump 3 parsecs, drop 9 units off at the cache point,

跳到 3 秒差距处， 放下 9 单位燃料，

and then jump the 3 units home, arriving with an empty tank.

接着，跳3个秒差距回原点， 燃料箱正好空了。

Repeating this process gets you 18 units of fuel at the cache point,

重复此过程，并在 缓存处存 18 单位燃料，

and one more jump puts you at the 3-parsec cache with 30 total units of fuel.

再跳一次到达 3 秒差距处时， 此时共有 30 单位燃料。

So far so good!

目前一切很顺利!

Next, you jump to the 8-parsec mark,

接下来，你跳到 8 秒差距处，

drop off 5 units of fuel, and jump back to the 3-parsec mark.

扔下 5 单位燃料， 再跳回 3 秒差距处，

You fill up your tank and jump forward again,

燃料箱填满后，继续往前跳，

arriving with 10 units of fuel in your tank.

再次到达 8 秒差距时， 燃料箱剩 10 单位燃料，

And now the end is in sight.

此时，终点已近在眼前。

You beam the 5 units of fuel in from deep space to fill your tank to capacity,

你从深空抓取 5 单位燃料， 塞满燃料箱，

and type in the coordinates of your final destination.

并输入终点坐标。

A 15-parsec jump leaves you running on fumes,

飞行 15 秒差距耗尽了所有燃料，

but ready to dock with the precursor space station.

但你已准备与先驱空间站对接。

Time to put this alien tech to work

是时候发挥外星科技的作用，

and make life better for everyone in the galaxy.

让银河系每个人的生活变得更美好了！