Why is everyone fighting over these tiny spots of space? - Fabio Pacucci

譯者: 柏陞 郭 審譯者: SF Huang

Since the launch of the first artificial satellite in 1957,

自 1957 年第一顆人造衛星 發射以來，

governments, companies, and research institutions

多國政府、眾多的企業和研究機構

have been planting flags among the stars.

前仆後繼地探索著宇宙的繁星。

But while it might seem like there's plenty of room in this vast expanse,

然而這宇宙看似如此開闊，

some pieces of celestial real estate are more valuable than others.

卻僅有少部分的區域值得人類關注。

Each of these dots is a Lagrange point,

現在所顯示的空間位置 稱為拉格朗日點。

and as far as human space exploration is concerned,

在人類探索太空看來，

they may be the most important places in our solar system.

它們可能是我們太陽系中 最重要的座標點。

Named after the 18th century mathematician who deduced their positions,

這個名字源自於 18 世紀， 推算出它們的數學家。

Lagrange points are rare places of equilibrium

拉格朗日點可說是我們 瞬息萬變的宇宙中少見的平衡點。

in our constantly shifting universe.

All celestial bodies exert a gravitational force on nearby objects,

天體對鄰近的物體施加引力

pulling them in and out of orbits.

使其在軌道上運行。

And gravity acts alongside several apparent forces

星體間各種引力的相互影響， 則形成軌道的運行軌跡。

to determine what those orbits look like.

However, Lagrange points are places where all these forces balance out.

拉格朗日點之所以特別， 是因為該處達成引力的平衡。

So if we place a relatively low mass object here,

如果我們把一個質量相對小的 物體放在那裡，

it will maintain a constant distance from the massive bodies pulling on it.

它便會與施加引力的星體 保持固定距離。

Essentially, Lagrange points are celestial parking spaces—

也就是說這些座標是 絕佳的星際停靠點—

once an object is there, it requires little to no energy to stay put.

停駐該處的物體幾乎不太消耗能量。

So whenever humans want to keep an object in one place for a long time

因此，假如人類需要將一個物體 長時間停駐在某處

without using tons of fuel,

又不需耗費過多燃料，

it needs to be orbiting a Lagrange point.

拉格朗日點必定是首選位置。

However, there are only so many of these parking spots.

但是在這麼多選擇裡， 卻僅有少數能為人類所用。

Pairs of massive bodies in our solar system

在太陽系中，每一對星球 都能找出五個拉格朗日點。

generate sets of five Lagrange points.

This means our Sun has five points with every planet,

若以此類推：太陽與每一顆行星，

and our planets have five points with each of their moons.

甚至是每一顆行星與它們的每顆衛星 都能找到專屬的五個點。

Adding these up, there are over 1,000 Lagrange points in our solar system—

加總起來的話，那麼太陽系中有 超過 1000 個拉格朗日點，

but only a few are useful for human purposes.

但只有少數能為人類所用。

Many are in locations that are too difficult to reach

大多數若非遙不可及，

or simply not very useful.

就是難以善加利用，

And for reasons we'll explain in a bit, many others are unstable.

又或者是環境不太穩定等原因， 至於理由待會兒說明。

Currently, only two of these points are heavily used by humans.

目前人類高度利用的點只有兩個。

But we’ll likely use many more in the future—

不過我們希望未來能盡力 開發其他的點，

making these limited points exclusive real estate.

然後把這些地區打造成 太空中的精華地段。

Which begs the question: what exactly should we park in them?

這又衍生了下一個問題： 我們應該把哪些設施停靠在那呢？

That answer depends on where each point is.

這個答案取決於其所在的位置。

Consider the five Lagrange points generated by the Sun and the Earth.

以太陽和地球的五個拉格朗日點為例：

L1 is located inside Earth's orbit,

L1 位在地球的公轉軌道內，

about 1.5 million kilometers away from the planet.

約距離地球 150 萬公里的位置。

With this panoramic view of the Sun, unobstructed by Earth’s shadow,

這裡能清楚地觀測到太陽的全貌 不受地球陰影的阻擋，

L1 is the perfect place for solar-observing satellites.

設置太陽觀測衛星再適合不過。

L2 is at the same distance from Earth but outside its orbit

L2 和地球同樣相距 150 萬公里 ， 但位於地球軌道外側。

and shielded from the Sun,

此處因不受太陽光照射，

making it the perfect spot to observe outer space.

適合作為觀測外太空的地點。

In 2022, the James Webb Space Telescope went online here,

詹姆斯·韋伯太空望遠鏡， 就是 2022 年在此開始服役的。

in a spot where the Sun and Earth only occupy a tiny fraction of the sky.

從這裡望去，太陽與地球 不過是蒼穹的一隅。

L3 is in a particularly mysterious location

L3 是從地球無法直接觀測的 一個特別神秘的位置。

that can never be directly observed from Earth’s surface.

This has made L3 a frequent locale in science fiction,

所以科幻小說經常以此地為背景，

though it hasn’t offered much use to scientists yet.

即便現實中科學家還沒想出 這裡有什麼用途。

L4 and L5, however, are a bit different from their siblings.

至於 L4 和 L5 相較於 其他點有些特別。

In every set of five, the first three Lagrange points are slightly unstable.

在每組的拉格朗日點中， 前三個點都有些不穩定的情況。

This means objects will slowly drift away from them,

意思是說物體仍會稍微位移，

though keeping what we’ve parked there in place is still energetically cheap.

但將設備停靠在這裡仍相對節省燃料。

The stability of L4 and L5, however, varies from set to set.

而 L4 和 L5 的穩定度則取決於 每組星球的質量。

If the heavier of the two bodies generating the points

在產生點的 2 顆星球裡，

has less than 25 times the mass of the lighter body,

若質量大的星球 小於質量小的星球的 25 倍，

these points are too unstable to park things in.

這些點因為太不穩定而不適合停靠。

However, if the heavier body is massive enough— like it is in Sun-Earth set—

假如有滿足這項條件， — 正如太陽與地球的組合—

then the relevant forces will always return objects

物體因達到引力平衡而能穩定停駐，

to these equilibrium points,

making them our most stable parking spots.

這裡就能做為可靠的休息站。

That’s why points like these naturally accumulate space objects,

這也是為什麼天體通常聚集於這兩點。

such as the Sun-Jupiter set’s L4 and L5, which host thousands of asteroids.

好比太陽跟金星的組合中， 這兩點就積累數以千計的小行星。

Every Lagrange point in our solar system has its quirks.

太陽系中的每一個 拉格朗日點都有其特性。

Some might be perfect for scavenging construction materials

有的可以做為絕佳的 建築材料採集點；

from drifting asteroids.

Others might make ideal gas stations for ships headed to deep space,

有的則適合建立太空船加油站， 以便前往宇宙更深處，

or even host entire human colonies.

或著打造成人類的太空殖民地。

These points are already home to advanced technological achievements,

當代先進科技早已在此插旗駐足，

but soon, they could become our stepping stones to the stars.

相信再過不久，這些地點就會變成 我們探索宇宙的大跳板。