Whoever builds something here will be rich beyond measure - Fabio Pacucci

341,280 views ・ 2023-08-10

TED-Ed


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翻译人员: gigide Hulu 校对人员: Jacky He
00:07
Since the launch of the first artificial satellite in 1957,
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自 1957 年第一颗 人造卫星发射以来,
00:11
governments, companies, and research institutions
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政府、公司和研究机构
00:14
have been planting flags among the stars.
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一直在给行星们添上旗帜。
00:16
But while it might seem like there's plenty of room in this vast expanse,
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虽然宇宙空间不可估量,
00:20
some pieces of celestial real estate are more valuable than others.
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有些天文位置比其他更有价值。
00:25
Each of these dots is a Lagrange point,
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这其中每一个点都是拉格朗日点 (Lagrange point),
00:28
and as far as human space exploration is concerned,
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而对人类太空探索而言,
00:31
they may be the most important places in our solar system.
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它们可能是我们 太阳系中最重要的地点。
00:35
Named after the 18th century mathematician who deduced their positions,
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拉格朗日点为推导出其位置的 18 世纪数学家而命名,
00:39
Lagrange points are rare places of equilibrium
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它在我们不断运动的宇宙中,
00:43
in our constantly shifting universe.
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是罕见的平衡点。
00:45
All celestial bodies exert a gravitational force on nearby objects,
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所有天体会对附近的物体施加引力,
00:50
pulling them in and out of orbits.
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将它们拉入和拉出轨道。
00:52
And gravity acts alongside several apparent forces
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重力与几种表观力一起作用,
00:56
to determine what those orbits look like.
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确定了这些轨道形状。
00:59
However, Lagrange points are places where all these forces balance out.
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但是,拉格朗日点是所有 这些力平衡的地方。
01:04
So if we place a relatively low mass object here,
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因此,如果我们在这里放置一个 质量相对较低的物体,
01:08
it will maintain a constant distance from the massive bodies pulling on it.
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它将与吸引它的巨大天体 保持恒定的距离。
01:13
Essentially, Lagrange points are celestial parking spaces—
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从本质上讲,拉格朗日点 像天体停车位——
01:17
once an object is there, it requires little to no energy to stay put.
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一旦物体在那里,它几乎 不需要任何能量便可留在原地。
01:21
So whenever humans want to keep an object in one place for a long time
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因此,当人类希望不消耗大量燃料
01:26
without using tons of fuel,
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将物体长时间保留在一个地方时,
01:28
it needs to be orbiting a Lagrange point.
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它得绕着拉格朗日点运行。
01:31
However, there are only so many of these parking spots.
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但是,停车位只有那么多。
01:35
Pairs of massive bodies in our solar system
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太阳系中每对大型天体
01:38
generate sets of five Lagrange points.
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会产生五个拉格朗日点。
01:41
This means our Sun has five points with every planet,
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这意味着我们的太阳与 每个行星都有五个点,
01:45
and our planets have five points with each of their moons.
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而我们的行星与 各颗卫星也有五个点。
01:49
Adding these up, there are over 1,000 Lagrange points in our solar system—
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加起来我们太阳系中的 拉格朗日点超过 1,000 个,
01:53
but only a few are useful for human purposes.
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但只有少数对人类有用。
01:57
Many are in locations that are too difficult to reach
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许多点的位置难以到达,
01:59
or simply not very useful.
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或是用处不大。
02:01
And for reasons we'll explain in a bit, many others are unstable.
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许多点也不稳定, 这我们会稍后解释。
02:06
Currently, only two of these points are heavily used by humans.
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目前,其中只有两个点 被人类广泛使用。
02:10
But we’ll likely use many more in the future—
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但在未来我们可能会 使用更多的点——
02:13
making these limited points exclusive real estate.
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把这些有限的点转成特权地点。
02:16
Which begs the question: what exactly should we park in them?
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这就引出了一个问题: 我们到底应该在里面停什么?
02:21
That answer depends on where each point is.
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这个答案 取决于每个点在哪里。
02:24
Consider the five Lagrange points generated by the Sun and the Earth.
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以太阳和地球产生的 五个拉格朗日点为例。
02:28
L1 is located inside Earth's orbit,
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L1 位于地球轨道内,
02:31
about 1.5 million kilometers away from the planet.
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距离地球约 150 万公里。
02:35
With this panoramic view of the Sun, unobstructed by Earth’s shadow,
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L1 不被地球遮挡, 可见到太阳全景,
02:40
L1 is the perfect place for solar-observing satellites.
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是太阳观测卫星的理想地点。
02:44
L2 is at the same distance from Earth but outside its orbit
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L2 与地球的距离相同, 但在轨道之外,
02:49
and shielded from the Sun,
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在太阳的阴影中,
02:51
making it the perfect spot to observe outer space.
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使其成为观测外部太空的理想地点。
02:54
In 2022, the James Webb Space Telescope went online here,
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2022 年,詹姆斯·韦伯 太空望远镜在这里部署;
03:00
in a spot where the Sun and Earth only occupy a tiny fraction of the sky.
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在这里,太阳和地球 只占天空的很小一块。
03:05
L3 is in a particularly mysterious location
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L3 位于一个特别神秘的地方,
03:08
that can never be directly observed from Earth’s surface.
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永远无法从地球表面观察到。
03:12
This has made L3 a frequent locale in science fiction,
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这使得 L3 在 科幻小说中经常出现,
03:16
though it hasn’t offered much use to scientists yet.
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尽管它对科学家们用处不大。
03:19
L4 and L5, however, are a bit different from their siblings.
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而 L4 和 L5 和其余的略有不同。
03:23
In every set of five, the first three Lagrange points are slightly unstable.
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在每五个点中, 前三个拉格朗日点略微不稳定。
03:29
This means objects will slowly drift away from them,
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这意味着物体会慢慢地远离它们,
03:32
though keeping what we’ve parked there in place is still energetically cheap.
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但使我们停在那里的东西 留在原地并非难事。
03:37
The stability of L4 and L5, however, varies from set to set.
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而 L4 与 L5 的稳定性 取决于天体对。
03:42
If the heavier of the two bodies generating the points
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如果两个天体中较重的天体
03:45
has less than 25 times the mass of the lighter body,
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质量不足较轻天体的 25 倍,
03:49
these points are too unstable to park things in.
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这些点就会不稳定, 物体无法在其中停靠。
03:52
However, if the heavier body is massive enough— like it is in Sun-Earth set—
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但是,如果较重的物体足够大, 如太阳、地球这组天体,
03:58
then the relevant forces will always return objects
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那么这些力会使
04:02
to these equilibrium points,
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物体待在平衡点,
04:04
making them our most stable parking spots.
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使它们成为最稳定的停车点。
04:07
That’s why points like these naturally accumulate space objects,
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这便是为什么类似的点 会积聚太空物体的原因,
04:11
such as the Sun-Jupiter set’s L4 and L5, which host thousands of asteroids.
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例如太阳、木星的 L4 和 L5, 聚集着上千个小行星。
04:18
Every Lagrange point in our solar system has its quirks.
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太阳系中的每个 拉格朗日点都有其特点。
04:21
Some might be perfect for scavenging construction materials
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有些可能非常适合
04:24
from drifting asteroids.
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从漂移的小行星中开采建筑材料。
04:26
Others might make ideal gas stations for ships headed to deep space,
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其他可以成为前往深空中 飞船的理想加油站,
04:31
or even host entire human colonies.
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甚至容纳完整的人类殖民地。
04:34
These points are already home to advanced technological achievements,
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这些地点已经存在着先进技术设备,
04:38
but soon, they could become our stepping stones to the stars.
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但不久,它们也许成为 我们通往星空的基地。
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