Carolyn Porco: This is Saturn

56,130 views ・ 2007-10-12

TED


請雙擊下方英文字幕播放視頻。

譯者: Lili Liang 審譯者: Adrienne Lin
00:25
In the next 18 minutes, I'm going to take you on a journey.
0
25000
3000
在接下來的18分鐘裡,我將帶大家去旅行。
00:28
And it's a journey that you and I have been on for many years now,
1
28000
5000
我們的旅程已經經歷很多年了,
00:33
and it began some 50 years ago, when humans first stepped off our planet.
2
33000
6000
50年前,人類第一次涉足外太空時,這段旅程便開始了。
00:39
And in those 50 years, not only did we literally, physically set foot on the moon,
3
39000
7000
在這50年裡,我們不僅成功地登上了月球,
00:46
but we have dispatched robotic spacecraft to all the planets -- all eight of them --
4
46000
7000
還把太空船發射到了太陽系中的八大行星上
00:53
and we have landed on asteroids, we have rendezvoused with comets,
5
53000
4000
我們在隕星上著陸,與彗星相遇,
00:57
and, at this point in time, we have a spacecraft on its way to Pluto,
6
57000
5000
現在這一刻,我們有一架太空飛船正向冥王星駛去,
01:02
the body formerly known as a planet.
7
62000
3000
飛向這顆曾被認為是行星的星球。
01:05
And all of these robotic missions are part of a bigger human journey:
8
65000
6000
所有這些機械裝置的出使任務都是為了將來實現載人航空。
01:11
a voyage to understand something, to get a sense of our cosmic place,
9
71000
7000
它們幫助我們了解宇宙,
01:18
to understand something of our origins, and how Earth, our planet,
10
78000
5000
了解我們的本源,了解我們的家園地球,
01:23
and we, living on it, came to be.
11
83000
2000
過去的狀態,
01:25
And of all the places in the solar system that we might go to
12
85000
3000
了解太陽系中所有我們想去的地方,
01:28
and search for answers to questions like this,
13
88000
4000
找到所有類似問題的答案。
01:32
there's Saturn. And we have been to Saturn before --
14
92000
3000
這是土星。我們曾經到過土星。
01:35
we visited Saturn in the early 1980s --
15
95000
3000
1980年代早期我們探訪過土星。
01:38
but our investigations of Saturn have become far more in-depth in detail
16
98000
5000
而現在,我們對土星的研究比當時更加深入、仔細。
01:43
since the Cassini spacecraft, traveling across interplanetary space
17
103000
4000
卡西尼號太空飛船穿梭於行星之間
01:47
for seven years, glided into orbit around Saturn in the summer of 2004,
18
107000
6000
長達七年之久,它2004年駛入土星運行軌道,
01:53
and became at that point the farthest robotic outpost
19
113000
3000
成為當時人類發射到太陽系中
01:56
that humanity had ever established around the Sun.
20
116000
3000
距離地球最遠的機械裝置。
01:59
Now, the Saturn system is a rich planetary system.
21
119000
5000
現在,土星是一個龐大而複雜的行星系統。
02:04
It offers mystery, scientific insight and obviously splendor beyond compare,
22
124000
7000
它是如此神祕,充滿了無與倫比的科學研究價值,
02:11
and the investigation of this system has enormous cosmic reach.
23
131000
4000
這個系統的勘察,對宇宙學的發展擁有極其深遠的意義。
02:15
In fact, just studying the rings alone, we stand to learn a lot
24
135000
4000
實際上,單是從土星的光環中我們就能學到很多
02:19
about the discs of stars and gas that we call the spiral galaxies.
25
139000
5000
關於星星可視圓面和旋渦星雲的知識。
02:24
And here's a beautiful picture of the Andromeda Nebula,
26
144000
2000
這裡有一張仙女星雲的照片,非常漂亮,
02:26
which is our closest, largest spiral galaxy to the Milky Way.
27
146000
4000
這是離銀河系最近,體積最大的旋渦星系。
02:30
And then, here's a beautiful composite of the Whirlpool Galaxy,
28
150000
3000
這是渦狀星系,它的構造異常美麗。
02:33
taken by the Hubble Space Telescope.
29
153000
2000
這是由哈勃太空望遠鏡所拍攝的。
02:35
So the journey back to Saturn is really part of and is also a metaphor
30
155000
6000
飛往土星的這段旅程真是 -- 一個形象的比喻 --
02:41
for a much larger human voyage
31
161000
2000
是人類漫長探索之旅的重要部份。
02:43
to understand the interconnectedness of everything around us,
32
163000
4000
我們通過探索去了解身邊事物之間的聯繫,
02:47
and also how humans fit into that picture.
33
167000
3000
了解人類為何存在。
02:50
And it pains me that I can't tell you all that we have learned with Cassini.
34
170000
7000
我很愧疚,在過去的兩年半時間裡,我因為太忙了,
02:57
I can't show you all the beautiful pictures that we've taken
35
177000
3000
而沒有向大家展示我們通過卡西尼號探測器收集的信息
03:00
in the last two and a half years, because I simply don't have the time.
36
180000
3000
和所有我們拍攝到的無比壯觀的圖片。
03:03
So I'm going to concentrate on two of the most exciting stories
37
183000
4000
下面我會講一講這次長達兩年的探索土星之旅,
03:07
that have emerged out of this major exploratory expedition
38
187000
4000
我想重點講這次重大探索之旅中
03:11
that we are conducting around Saturn,
39
191000
2000
發生的兩件
03:13
and have been for the past two and a half years.
40
193000
3000
最令人心潮澎湃的事情。
03:16
Saturn is accompanied by a very large and diverse collection of moons.
41
196000
4000
陪伴在土星周圍的是眾多體積龐大,形狀各異的衛星。
03:20
They range in size from a few kilometers across to as big across as the U.S.
42
200000
5000
有些衛星的直徑有幾公里,而有些衛星的直徑可以橫跨整個美國。
03:25
Most of the beautiful pictures we've taken of Saturn, in fact,
43
205000
3000
我們拍攝到的這些土星美圖基本上
03:28
show Saturn in accompaniment with some of its moons. Here's Saturn with Dione,
44
208000
5000
都有土星和圍繞著它的衛星。這是土星和土衛四戴奧妮,
03:33
and then, here's Saturn showing the rings edge-on,
45
213000
3000
這是土衛二和土星最外圍的光環,
03:36
showing you just how vertically thin they are, with the moon Enceladus.
46
216000
4000
從縱向看,它們有多薄。
03:40
Now, two of the 47 moons that Saturn has are standouts.
47
220000
5000
在土星47顆衛星中,有兩顆特別耀眼。
03:45
And those are Titan and Enceladus. Titan is Saturn's largest moon,
48
225000
5000
它們分別是土衛六泰坦和土衛二恩克拉多斯。泰坦是土星最大的衛星,
03:50
and, until Cassini had arrived there,
49
230000
2000
在卡西尼號到達之前,
03:52
was the largest single expanse of unexplored terrain
50
232000
4000
它是我們在太陽系中最大的,
03:56
that we had remaining in our solar system.
51
236000
4000
未經勘探的單獨地帶。
04:00
And it is a body that has long intrigued people who've watched the planets.
52
240000
4000
它是長期以來研究這些行星的人們朝思暮想的一塊寶地。
04:04
It has a very large, thick atmosphere,
53
244000
4000
它的大氣層非常厚,
04:08
and in fact, its surface environment was believed to be
54
248000
4000
事實上,它的地表環境被認為是
04:12
more like the environment we have here on the Earth,
55
252000
4000
接近於地球上的環境。
04:16
or at least had in the past, than any other body in the solar system.
56
256000
4000
至少在過去,人們認為它比其它太陽系中的天體更接近。
04:20
Its atmosphere is largely molecular nitrogen, like you are breathing here in this room,
57
260000
5000
它的大氣中含有大量氮分子,就跟你們在這裡吸入的氮氣一樣,
04:25
except that its atmosphere is suffused with
58
265000
2000
只不過裡面有過量
04:27
simple organic materials like methane and propane and ethane.
59
267000
4000
簡單有機物
04:31
And these molecules high up in the atmosphere of Titan
60
271000
3000
這些氣體分子散佈在土衛六大氣的頂層,
04:34
get broken down, and their products join together to make haze particles.
61
274000
5000
分解之後,它們的產物化合成霧狀顆粒。
04:39
This haze is ubiquitous. It's completely global and enveloping Titan.
62
279000
5000
這些霧狀物四處擴散,把土衛六完全包裹起來。
04:44
And that's why you cannot see down to the surface
63
284000
3000
所以單憑我們的肉眼視力,
04:47
with our eyes in the visible region of the spectrum.
64
287000
2000
根本無法看清它的表面。
04:49
But these haze particles, it was surmised,
65
289000
3000
但是在卡西尼號到達之前,我們推測,這些霧狀顆粒
04:52
before we got there with Cassini, over billions and billions of years,
66
292000
4000
經過上千億年的時間
04:56
gently drifted down to the surface and coated the surface
67
296000
4000
一點一點積聚並覆蓋在土衛六表面
05:00
in a thick organic sludge.
68
300000
1000
形成一層有機的泥狀物。
05:01
So like the equivalent, the Titan equivalent, of tar, or oil, or what -- we didn't know what.
69
301000
7000
就像泰坦上的焦油,油,或者類似的甚麼東西 -- 我們當時無法確定。
05:08
But this is what we suspected. And these molecules,
70
308000
2000
這是我們的推測。而這些分子,
05:10
especially methane and ethane, can be liquids at the surface temperatures of Titan.
71
310000
9000
尤其是甲烷和乙烷,它們在泰坦的地表溫度下會呈現液態。
05:19
And so it turns out that methane is to Titan what water is to the Earth.
72
319000
5000
結果發現,甲烷在土衛六上呈現出的狀態,就好跟水在地球上的狀態一樣,
05:24
It's a condensable in the atmosphere,
73
324000
2000
它在大氣中是會冷凝的,
05:26
and so recognizing this circumstance brought to the fore
74
326000
5000
所以認識到這種情況的存在之後,
05:31
a whole world of bizarre possibilities. You can have methane clouds, OK,
75
331000
5000
我們就有了千奇百怪的設想。可能那裡存在甲烷做的雲,是吧,
05:36
and above those clouds, you have this hundreds of kilometers of haze,
76
336000
3000
在這些雲之上,幾十萬米厚的霧狀顆粒層
05:39
which prevent any sunlight from getting to the surface.
77
339000
2000
遮擋住了陽光,使它無法到達地表。
05:41
The temperature at the surface is some 350 degrees below zero Fahrenheit.
78
341000
6000
地表的溫度為華氏零下350度(約攝氏零下212度)。
05:47
But despite that cold, you could have rain falling down on the surface of Titan.
79
347000
6000
即使在這樣的低溫下,土衛六上還是會出現降水。
05:53
And doing on Titan what rain does on the Earth: it carves gullies; it forms rivers
80
353000
3000
這些降水像地球上的雨水一樣,使地表形成溝渠,河流
05:56
and cataracts; it can create canyons; it can pool in large basins and craters.
81
356000
7000
以及瀑布。它還能形成峽谷,大型盆地,以及凹地。
06:03
It can wash the sludge off high mountain peaks and hills,
82
363000
3000
它能把泥狀物從高山丘陵上
06:06
down into the lowlands. So stop and think for a minute.
83
366000
3000
沖到低窪地帶。我們停下來想一想。
06:09
Try to imagine what the surface of Titan might look like.
84
369000
4000
想像土衛六的地表是甚麼樣子的。
06:13
It's dark. High noon on Titan is as dark as deep earth twilight on the Earth.
85
373000
5000
那裡一片黑暗 -- 土衛六上的中午時刻跟地球上黎明來臨之前一樣黑暗。
06:18
It's cold, it's eerie, it's misty,
86
378000
2000
那裡天寒地凍,陰森恐怖,迷霧重重,
06:20
it might be raining, and you might be standing
87
380000
3000
那裡可能正在下雨,而你可能正站在
06:23
on the shores of Lake Michigan brimming with paint thinner. (Laughter)
88
383000
4000
氾濫著塗料稀釋劑(成份為甲烷)的密歇根湖邊。
06:27
That is the view that we had of the surface of Titan before we got there with Cassini,
89
387000
5000
這是我們在卡西尼號到達土衛六之前的遐想,
06:32
and I can tell you that what we have found on Titan, though it is not the same in detail,
90
392000
7000
我可以告訴大家,我們真正在土衛六上發現的,跟我們的想像不盡相同,
06:39
is every bit as fascinating as that story is.
91
399000
3000
但是卻一樣引人入勝。
06:42
And for us, it has been like -- the Cassini people --
92
402000
2000
對於我們,也就卡西尼號的工作人員而言,
06:44
it has been like a Jules Verne adventure come true.
93
404000
4000
這段旅程就像是儒勒·凡爾納(《八十天環遊世界》作者)的小說在現實中上演。
06:48
As I said, it has a thick, extensive atmosphere.
94
408000
2000
我剛才說過,它有很厚的一層大氣。
06:50
This is a picture of Titan, backlit by the Sun, with the rings as a beautiful backdrop.
95
410000
5000
這張照片是土衛六在被對太陽時被拍下來的,它的光環構成了一幅壯麗的背景。
06:55
And yet another moon there --
96
415000
2000
而那裡是另一顆衛星 --
06:57
I don't even know which one it is. It's a very extensive atmosphere.
97
417000
3000
我都不知道究竟是哪一顆。這是個擴散得很開的大氣層。
07:00
We have instruments on Cassini which can see down to the surface
98
420000
3000
在卡西尼號上有專門儀器能夠幫助我們透過大氣層
07:03
through this atmosphere, and my camera system is one of them.
99
423000
4000
看到土衛六地表,我的成像科學子系統就是儀器之一。
07:07
And we have taken pictures like this.
100
427000
2000
我們拍下了這些照片。
07:09
And what you see is bright and dark regions, and that's about as far as it got for us.
101
429000
5000
你看到的是明於暗的地帶,這是儀器能拍到的最近距離。
07:14
It was so mystifying: we couldn't make out what we were seeing on Titan.
102
434000
4000
那裡霧太大了 -- 我們無法確定看到的是甚麼。
07:18
When you look closer at this region, you start to see things
103
438000
5000
當你湊近了看那塊區域,你可以看到一些物體,
07:23
like sinuous channels -- we didn't know. You see a few round things.
104
443000
4000
形狀像委蛇的溝渠,不知道是甚麼。還可以看到一些圓形圖案。
07:27
This, we later found out, is, in fact, a crater,
105
447000
2000
後來我們發現,這原來是一個殞坑,
07:29
but there are very few craters on the surface of Titan,
106
449000
3000
但是,土衛六表面的殞坑數量很少,
07:32
meaning it's a very young surface.
107
452000
2000
這說明土衛六的地表非常年輕。
07:34
And there are features that look tectonic.
108
454000
2000
上面有一些像是由地殻運動產生的地表特徵。
07:36
They look like they've been pulled apart.
109
456000
2000
地表像是被外力撕裂了一般。
07:38
Whenever you see anything linear on a planet,
110
458000
2000
如果你看到行星表面的一些線形圖案,
07:40
it means there's been a fracture, like a fault.
111
460000
4000
那就是地表的裂隙,比如一個斷層。
07:44
And so it's been tectonically altered.
112
464000
2000
也就是說土衛六發生過地殻運動。
07:46
But we couldn't make sense of our images,
113
466000
2000
但是我們還是無法解讀這些圖像,
07:48
until, six months after we got into orbit,
114
468000
4000
直到我們進入軌道六個月之後,
07:52
an event occurred that many have regarded
115
472000
2000
一件重大事件發生了。它後來被許多人譽為
07:54
as the highlight of Cassini's investigation of Titan.
116
474000
3000
卡西尼號突探測土衛六的突出成就。
07:57
And that was the deployment of the Huygens probe,
117
477000
3000
這就是惠更斯號探測器的成功發射。
08:00
the European-built Huygens probe that Cassini had carried
118
480000
3000
這個探測器在歐洲被研製出來,乘著卡西尼號
08:03
for seven years across the solar system. We deployed it to the atmosphere of Titan,
119
483000
4000
在浩瀚的太陽系里穿梭了七年。我們把它發射到土衛六的大氣中,
08:07
it took two and a half hours to descend, and it landed on the surface.
120
487000
4000
兩個半小時之後,它在地表著陸。
08:11
And I just want to emphasize how significant an event this is.
121
491000
4000
我真想強調一下這一行動的重大意義。
08:15
This is a device of human making,
122
495000
3000
這是人類歷史上第一次有人造的機器
08:18
and it landed in the outer solar system for the first time in human history.
123
498000
4000
在外太陽系的天體上登陸。
08:22
It is so significant that, in my mind,
124
502000
4000
在我心目中,它實在是意義非凡,
08:26
this was an event that should have been celebrated
125
506000
2000
我們值得為它
08:28
with ticker tape parades in every city across the U.S. and Europe,
126
508000
5000
在美國,歐洲的大街小巷敲鑼打鼓,舉行盛大遊行,
08:33
and sadly, that wasn't the case.
127
513000
2000
真遺憾,這沒有得到響應。
08:35
(Laughter).
128
515000
2000
(眾人笑)
08:37
It was significant for another reason. This is an international mission,
129
517000
3000
另一個顯示其重大意義的理由是,這是一項國際合作項目,
08:40
and this event was celebrated in Europe, in Germany,
130
520000
3000
在德國,人們為此事舉行了歡慶活動,
08:43
and the celebratory presentations were given in English accents,
131
523000
4000
慶典節目的表演者有英國人,
08:47
and American accents, and German accents, and French and Italian and Dutch accents.
132
527000
6000
美國人,德國人,法國人,義大利人,和荷蘭人。
08:53
It was a moving demonstration of what the words
133
533000
4000
這是在用行動來詮釋
08:57
"united nations" are supposed to mean:
134
537000
2000
“聯合國”一詞的真諦:
08:59
a true union of nations joined together in a colossal effort for good.
135
539000
6000
國家之間真誠團結協作,眾志成城。
09:05
And, in this case, it was a massive undertaking to explore a planet,
136
545000
4000
探測一顆遙不可及的星球
09:09
and to come to understand a planetary system
137
549000
3000
並試圖了解一個星球的體系
09:12
that, for all of human history, had been unreachable,
138
552000
4000
需要耗費龐大的人力物力。
09:16
and now humans had actually touched it.
139
556000
2000
而現在,人類終於到達了這樣一個星球。
09:18
So it was -- I mean, I'm getting goose bumps just talking about it.
140
558000
4000
這真是 -- 我只是說一下,就開始起雞皮疙瘩了,
09:22
It was a tremendously emotional event,
141
562000
2000
這的確是激動人心的一件事,
09:24
and it's something that I will personally never forget, and you shouldn't either.
142
564000
5000
它讓我永生難忘,你們也應該有同感。
09:29
(Applause).
143
569000
6000
(眾人鼓掌)
09:35
But anyway, the probe took measurements of the atmosphere on the way down,
144
575000
3000
探測器在降落過程中對大氣進行了測量,
09:38
and it also took panoramic pictures.
145
578000
2000
並且拍攝了全景照片。
09:40
And I can't tell you what it was like to see the first pictures
146
580000
4000
我無法用言語來表達第一次看到土衛六地表照片時
09:44
of Titan's surface from the probe. And this is what we saw.
147
584000
4000
我的心情有多麼激動。這是我們看到的景象。
09:48
And it was a shocker, because it was everything we wanted
148
588000
3000
太令人震驚了,這些從土星軌道上拍攝的景象
09:51
those other pictures taken from orbit to be.
149
591000
2000
和我們的設想正好吻合。
09:53
It was an unambiguous pattern, a geological pattern.
150
593000
4000
地表呈現出清晰的幾何圖案。
09:57
It's a dendritic drainage pattern that can be formed only by the flow of liquids.
151
597000
5000
它所呈現出的樹枝狀水流圖案,肯定是因液體的流動而形成的。
10:02
And you can follow these channels
152
602000
2000
你可以沿著這些溝渠
10:04
and you can see how they all converge.
153
604000
1000
找到它們的匯合點。
10:05
And they converge into this channel here, which drains into this region.
154
605000
4000
它們匯聚到這條溝里,從這裡滲透到地下。
10:09
You are looking at a shoreline.
155
609000
2000
你們看到的是一條海岸線。
10:11
Was this a shoreline of fluids? We didn't know.
156
611000
3000
這是液體的海岸線嗎?我們不知道。
10:14
But this is somewhat of a shoreline.
157
614000
2000
但是,這肯定是一條海岸線。
10:16
This picture is taken at 16 kilometers.
158
616000
2000
這是在離地表16公里的高度所拍攝的照片。
10:18
This is the picture taken at eight kilometers, OK? Again, the shoreline.
159
618000
4000
這張是在8公里的高度拍攝的。看,還是那條海岸線。
10:22
Okay, now, 16 kilometers, eight kilometers -- this is roughly an airline altitude.
160
622000
5000
好,16公里,8公里 -- 大概就是普通飛機的飛行高度。
10:27
If you were going to take an airplane trip across the U.S.,
161
627000
3000
如果你乘飛機橫跨美國,
10:30
you would be flying at these altitudes.
162
630000
2000
這就相當於你的飛行高度。
10:32
So, this is the picture you would have at the window of Titanian Airlines
163
632000
4000
假如你正乘坐著土衛六航空公司的飛機俯瞰土衛六,
10:36
as you fly across the surface of Titan. (Laughter)
164
636000
3000
你看到的就是這副景象。(眾人笑)
10:39
And then finally, the probe came to rest on the surface,
165
639000
4000
最後,探測器在地面著陸。
10:43
and I'm going to show you, ladies and gentlemen,
166
643000
2000
女士們,先生們,下面我為你們展示
10:45
the first picture ever taken from the surface of a moon in the outer solar system.
167
645000
4000
首張外太陽系衛星表面的照片。
10:49
And here is the horizon, OK?
168
649000
4000
這裡是地平線,看見了嗎?
10:53
These are probably water ice pebbles, yes?
169
653000
4000
這些很可能是冰鵝卵石。
10:57
(Applause).
170
657000
5000
(眾人鼓掌)
11:02
And obviously, it landed in one of these flat, dark regions
171
662000
4000
很明顯,它落在了其中一塊平坦的陰影地帶。
11:06
and it didn't sink out of sight. So it wasn't fluid that we landed in.
172
666000
5000
它沒有沉沒消失,這說明它沒有落在液體上。
11:11
What the probe came down in was basically
173
671000
3000
實際上,它降落的地點
11:14
the Titan equivalent of a mud flat.
174
674000
3000
類似於一灘淤泥。
11:17
This is an unconsolidated ground that is suffused with liquid methane.
175
677000
5000
這是液態甲烷形成的半流體。
11:22
And it's probably the case that this material
176
682000
3000
形成這種地貌的原因可能是
11:25
has washed off the highlands of Titan
177
685000
4000
液態甲烷順著我們剛才看到的那些溝渠
11:29
through these channels that we saw,
178
689000
1000
沖蝕了土衛六上的高地,
11:30
and has drained over billions of years to fill in low-lying basins.
179
690000
4000
滲透並填充到低窪地帶長達幾十億年的時間。
11:34
And that is what the Huygens probe landed in.
180
694000
3000
這就是惠更斯號探測器著陸的地方。
11:37
But still, there was no sign in our images,
181
697000
4000
然而,我們還是沒有看到我們之前預想的
11:41
or even in the Huygens' images, of any large, open bodies of fluids.
182
701000
5000
或者惠更斯號圖片上顯示的大面積液體。
11:46
Where were they? It got even more puzzling when we found dunes.
183
706000
5000
都在哪裡呢?當我們看到一些沙丘時,我們就更加困惑了。
11:51
OK, so this is our movie of the equatorial region of Titan,
184
711000
3000
這里是土衛六赤道地帶的錄像,
11:54
showing these dunes. These are dunes that are 100 meters tall,
185
714000
3000
這些就是上面的沙丘。它們高達100米,
11:57
separated by a few kilometers,
186
717000
3000
之間相隔幾公里遠,
12:00
and they go on for miles and miles and miles.
187
720000
3000
延綿數千英里。
12:03
There's hundreds, up to a 1,000 or 1,200 miles of dunes.
188
723000
3000
這些沙丘帶短則幾百英里,長則1000到1200英里。
12:06
This is the Saharan desert of Titan.
189
726000
3000
這簡直就相當於土衛六的撒哈拉沙漠。
12:09
It's obviously a place which is very dry, or you wouldn't get dunes.
190
729000
5000
顯然,這裡非常乾燥,否則不會有沙丘。
12:14
So again, it got puzzling that there were no bodies of fluid,
191
734000
5000
這讓人更加懷疑這裡是否有液態物存在,
12:19
until finally, we saw lakes in the polar regions.
192
739000
4000
直到我們最後看到了極地的湖泊。
12:23
And there is a lake scene in the south polar region of Titan.
193
743000
4000
這是土衛六南極的一個湖。
12:27
It's about the size of Lake Ontario.
194
747000
2000
它的大小相當於安大略湖。
12:29
And then, only a week and a half ago,
195
749000
1000
接著,也就一個多星期以後,
12:30
we flew over the north pole of Titan and found, again,
196
750000
4000
我們飛過北極,
12:34
we found a feature here the size of the Caspian Sea.
197
754000
5000
發現了相當於加勒比海大小的一片區域。
12:39
So it seems that the liquids, for some reason we don't understand,
198
759000
4000
不知為何,可能是這個季節的原因,土衛六上的液體,
12:43
or during at least this season, are apparently at the poles of Titan.
199
763000
5000
都出現在極地地帶。
12:48
And I think you would agree that we have found Titan
200
768000
3000
相信你們應該會同意,土衛六是一個
12:51
is a remarkable, mystical place. It's exotic, it's alien, but yet strangely Earth-like,
201
771000
7000
不可思議的地方。它是那麼特別,那麼遙遠,但又和地球有著驚人的相似處。
12:58
and having Earth-like geological formations
202
778000
3000
它有著像類似地球表面的地貌
13:01
and a tremendous geographical diversity,
203
781000
4000
和豐富的地質多樣性。
13:05
and is a fascinating world whose only rival in the solar system
204
785000
4000
它是個複雜而豐富多彩的世界,是太陽系中
13:09
for complexity and richness is the Earth itself.
205
789000
3000
唯一能和地球相媲美的天體。
13:12
And so now we go onto Enceladus. Enceladus is a small moon,
206
792000
5000
我們現在飛到土衛二看看。它是一個小型衛星,
13:17
it's about a tenth the size of Titan. And you can see it here next to England,
207
797000
4000
大小僅有土衛六的十分之一,可以和圖中旁邊的英國比較一下。
13:21
just to show you the size. This is not meant to be a threat.
208
801000
3000
我只是讓你們看看它的大小;沒有威脅英國的意思。
13:24
(Laughter).
209
804000
2000
(眾人笑)
13:26
And Enceladus is very white, it's very bright,
210
806000
4000
土衛二很白很亮,
13:30
and its surface is obviously wrecked with fractures.
211
810000
4000
它的表面有很明顯的裂痕,
13:34
It is a very geologically active body.
212
814000
2000
它的地殻運動很頻繁。
13:36
But the mother lode of discoveries on Enceladus
213
816000
2000
但是我們在土衛二上的發現
13:38
was found at the south pole -- and we're looking at the south pole here --
214
818000
3000
大多集中在它的南極地帶 -- 我們現在看到的就是南極 --
13:41
where we found this system of fractures.
215
821000
3000
在這裡,我們發現了一系列地裂。
13:44
And they're a different color because they're a different composition.
216
824000
2000
它們的顏色各有不同,這是因為它們的成份不同。
13:46
They are coated. These fractures are coated with organic materials.
217
826000
5000
它們的表面覆蓋著不同的有機物質。
13:51
Moreover, this whole, entire region, the south polar region,
218
831000
4000
這整個南極地帶
13:55
has elevated temperatures. It's the hottest place on the planet, on the body.
219
835000
4000
越往高處氣溫越高。這裡是整個星球溫度最高的地方。
13:59
That's as bizarre as finding that the Antarctic on the Earth is hotter than the tropics.
220
839000
5000
這現象非常奇特,想像地球南極洲比熱帶地區還熱會是甚麼情況。
14:04
And then, when we took additional pictures, we discovered
221
844000
3000
接著,我們拍攝了更多照片,
14:07
that from these fractures are issuing jets of fine, icy particles
222
847000
6000
我們發現從這些地裂中,有細小的冰粒噴射出來,
14:13
extending hundreds of miles into space.
223
853000
2000
噴射範圍為方圓幾百英里。
14:15
And when we color-code this image, to bring out the faint light levels,
224
855000
3000
我們對此作了光譜分析,
14:18
we see that these jets feed a plume
225
858000
4000
我們看到這些冰泉在土衛二的上空
14:22
that, in fact, we see, in other images, goes thousands of miles
226
862000
4000
呈現羽狀噴射,
14:26
into the space above Enceladus.
227
866000
2000
噴射高度達到幾千英里。
14:28
My team and I have examined images like this,
228
868000
3000
我們的團隊對這些圖片進行了分析,
14:31
and like this one, and have thought about the other results from Cassini.
229
871000
4000
這是其中一張,另外思考過卡西尼號的其它發現。
14:35
And we have arrived at the conclusion
230
875000
4000
我們做出這樣的結論,
14:39
that these jets may be erupting from pockets
231
879000
3000
這些噴射現象是由土衛二
14:42
of liquid water under the surface of Enceladus.
232
882000
4000
地表下的液態水,從冰缺口噴發而出所造成的。
14:46
So we have, possibly, liquid water, organic materials and excess heat.
233
886000
5000
那裡可能存在液態水,有機物質和過剩的熱量。
14:51
In other words, we have possibly stumbled upon
234
891000
3000
換句話說,我們很有可能湊巧
14:54
the holy grail of modern day planetary exploration,
235
894000
4000
發現了現代行星探索的新大陸。
14:58
or in other words, an environment that is potentially suitable for living organisms.
236
898000
4000
也就是說,我們找到了一片可能適合有機生命生長的環境。
15:02
And I don't think I need to tell you that the discovery of life
237
902000
3000
就算我不說,大家也知道,如果在太陽系其它地方
15:05
elsewhere in our solar system,
238
905000
2000
找到生命,
15:07
whether it be on Enceladus or elsewhere,
239
907000
2000
不管是在土衛二或其它甚麼地方,
15:09
would have enormous cultural and scientific implications.
240
909000
3000
對於在科學和文化領域,這都是巨大而深遠的衝擊。
15:12
Because if we could demonstrate that genesis had occurred
241
912000
4000
假如我們能夠證明《創世紀》中的神跡
15:16
not once, but twice, independently, in our solar system,
242
916000
4000
能夠在我們的太陽系中分別發生兩次,而不僅僅是一次,
15:20
then that means, by inference, it has occurred a staggering number of times
243
920000
4000
那麼,照此推斷,它在茫茫宇宙137億年的歷史中,
15:24
throughout the universe and its 13.7 billion year history.
244
924000
5000
肯定已經發生過無數次了。
15:29
Right now, Earth is the only planet still that we know is teeming with life.
245
929000
4000
目前,地球仍是唯一一顆有生命存在的星球。
15:33
It is precious, it is unique,
246
933000
3000
它是那麼珍貴,獨一無二。
15:36
it is still, so far, the only home we've ever known.
247
936000
3000
它依然是我們唯一的家園。
15:39
And if any of you were alert and coherent during the 1960s --
248
939000
7000
如果在座的哪位1960年代的時候頭腦還靈活 --
15:46
and we'd forgive you, if you weren't, OK --
249
946000
2000
不靈活也沒關係,
15:48
you would remember this very famous picture
250
948000
2000
你可能會認得1968年
15:50
taken by the Apollo 8 astronauts in 1968.
251
950000
4000
由阿波羅八號太空人拍下的這張著名照片。
15:54
It was the first time that Earth was imaged from space,
252
954000
3000
這是第一張從太空拍攝的地球照片。
15:57
and it had an enormous impact on our sense of place in the universe,
253
957000
3000
它極大地衝擊了我們對宇宙認識,
16:00
and our sense of responsibility for the protection of our own planet.
254
960000
5000
影響了我們保護地球的責任感。
16:05
Well, we on Cassini have taken an equivalent first,
255
965000
4000
我們的卡西尼號同樣拍下了一張
16:09
a picture that no human eye has ever seen before.
256
969000
4000
此前人們從未見過的照片。
16:13
It is a total eclipse of the Sun, seen from the other side of Saturn.
257
973000
4000
它是在日全蝕的時候,從土星的另一側拍攝的。
16:17
And in this impossibly beautiful picture,
258
977000
4000
在這張無與倫比的照片上
16:21
you see the main rings backlit by the Sun,
259
981000
2000
你們可以看見背著陽光的土星主光環,
16:23
you see the refracted image of the Sun
260
983000
3000
看到太陽折射後的形象,
16:26
and you see this ring created, in fact,
261
986000
2000
還可以看到由土衛二表面羽狀物
16:28
by the exhalations of Enceladus.
262
988000
3000
形成的光暈。
16:31
But as if that weren't brilliant enough, we can spot, in this beautiful image,
263
991000
6000
如果這些都還不夠引人入勝的話,我們還能在這美麗畫卷上
16:37
sight of our own planet,
264
997000
2000
找到我們的地球,
16:39
cradled in the arms of Saturn's rings.
265
999000
4000
它正依偎在土星光環的臂彎中。
16:43
Now, there is something deeply moving
266
1003000
2000
當我們從另一片天地
16:45
about seeing ourselves from afar,
267
1005000
2000
遙望我們自己,
16:47
and capturing the sight of our little, blue-ocean planet
268
1007000
3000
窺見到那眇小的,海藍色的地球
16:50
in the skies of other worlds.
269
1010000
2000
我們不能不為之動容。
16:52
And that, and the perspective of ourselves that we gain from that,
270
1012000
4000
也許,我們得到這個觀察的視角
16:56
may be, in the end, the finest reward that we earn
271
1016000
4000
就是我們在這次長達半個世紀的旅程中
17:00
from this journey of discovery that started half a century ago.
272
1020000
3000
最有價值的奬勵。
17:03
And thank you very much.
273
1023000
2000
非常感謝大家。
17:05
(Applause)
274
1025000
12000
(熱烈鼓掌)

Original video on YouTube.com
關於本網站

本網站將向您介紹對學習英語有用的 YouTube 視頻。 您將看到來自世界各地的一流教師教授的英語課程。 雙擊每個視頻頁面上顯示的英文字幕,從那裡播放視頻。 字幕與視頻播放同步滾動。 如果您有任何意見或要求,請使用此聯繫表與我們聯繫。

https://forms.gle/WvT1wiN1qDtmnspy7