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Anjali Tripathi: Why Earth may someday look like Mars
安佳丽 特里帕西: 为何地球终有一日将变成火星
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每一分钟就会有四百磅氢气和几乎七磅氦气从地球大气层飞向外太空。天体物理学家——安佳丽 特里帕西研究了大气逃离的现象。在此次精彩演讲中，她将介绍为何这个现象会在几百万年后的某一天，将我们蓝色的地球变成红色。
Anjali Tripathi - Astrophysicist
Anjali Tripathi explores planets to uncover the processes that make and destroy them. Full bio
Anjali Tripathi explores planets to uncover the processes that make and destroy them. Full bio
Double-click the English transcript below to play the video.
00:12
So when you look out
at the stars at night,
at the stars at night,
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當你擡頭看夜空中的繁星，
00:15
it's amazing what you can see.
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你所見到的，是多麼奇妙。
00:17
It's beautiful.
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多麽美好。
00:18
But what's more amazing
is what you can't see,
is what you can't see,
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但更奇妙的是那些你看不見的，
00:21
because what we know now
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因為根據人類已知，
00:23
is that around every star
or almost every star,
or almost every star,
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幾乎在每一顆恒星周圍
00:26
there's a planet,
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都有一颗行星，
00:27
or probably a few.
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甚至若幹個。
00:30
So what this picture isn't showing you
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這幅圖片沒能告訴你的是
00:32
are all the planets that we know about
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在這個宇宙中存在著的
00:34
out there in space.
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所有的行星。
00:36
But when we think about planets,
we tend to think of faraway things
we tend to think of faraway things
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當我們提起“行星”，我們總會覺得，它們是離我們很遙遠的東西
00:39
that are very different from our own.
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跟我們自己的星球很不一樣。
00:41
But here we are on a planet,
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但我們現在正正身處在一個行星，
00:43
and there are so many things
that are amazing about Earth
that are amazing about Earth
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而且有太多美妙的事物在這個地球，
00:47
that we're searching far and wide
to find things that are like that.
to find things that are like that.
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我們正在深入發掘和探索。
00:51
And when we're searching,
we're finding amazing things.
we're finding amazing things.
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當我們探索，我們就發現奇妙的事物。
00:54
But I want to tell you
about an amazing thing here on Earth.
about an amazing thing here on Earth.
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但今天我想告訴你們一件關於地球的奇妙的事，就是－－－
00:59
And that is that every minute,
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每分鐘內，
01:01
400 pounds of hydrogen
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四百磅的氫氣
01:04
and almost seven pounds of helium
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和將近七磅的氦氣
01:06
escape from Earth into space.
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正在從地球洩漏到宇宙中。
01:10
And this is gas that is going off
and never coming back.
and never coming back.
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這些氣體一去不復返。
01:15
So hydrogen, helium and many other things
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氫氣、氮氣、和很多其他氣體
01:18
make up what's known
as the Earth's atmosphere.
as the Earth's atmosphere.
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共同組成了我們所知的地球大氣。
01:21
The atmosphere is just these gases
that form a thin blue line
that form a thin blue line
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大氣層從國際空間站的視角來看，
01:25
that's seen here from
the International Space Station,
the International Space Station,
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就只是一層薄薄的藍色。
01:28
a photograph that some astronauts took.
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這是宇航員拍下的照片。
01:31
And this tenuous veneer around our planet
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正是這層稀薄的大氣，
01:34
is what allows life to flourish.
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讓地球上的生命欣欣向榮。
01:36
It protects our planet
from too many impacts,
from too many impacts,
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大氣保護地球，免受太多侵害，
01:39
from meteorites and the like.
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例如隕石墜落。
01:41
And it's such an amazing phenomenon
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但是事實上，
01:45
that the fact that it's disappearing
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這個奇妙的現象正在消失。
01:48
should frighten you,
at least a little bit.
at least a little bit.
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這應該讓你感到害怕，哪怕只是一點點。
01:52
So this process is something that I study
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這消失的過程就是我研究的領域——
01:55
and it's called atmospheric escape.
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“大氣逃離”。
01:58
So atmospheric escape
is not specific to planet Earth.
is not specific to planet Earth.
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“大氣逃離”的現象不僅僅發生在地球上；
02:03
It's part of what it means
to be a planet, if you ask me,
to be a planet, if you ask me,
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這個現象是被稱為“行星”的條件之一，
02:07
because planets, not just here on Earth
but throughout the universe,
but throughout the universe,
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因為不僅在地球上，在宇宙中的所有行星上，
02:11
can undergo atmospheric escape.
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都會發生“大氣逃離”現象。
02:14
And the way it happens actually tells us
about planets themselves.
about planets themselves.
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實際上，這個現象可以告訴我們關於行星本身。
02:19
Because when you think
about the solar system,
about the solar system,
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因為當你想到太陽系，
02:22
you might think about this picture here.
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你可能會想到這張圖片。
02:25
And you would say, well,
there are eight planets, maybe nine.
there are eight planets, maybe nine.
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你可能會說：這有八顆行星，可能是九顆。
02:29
So for those of you
who are stressed by this picture,
who are stressed by this picture,
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那些為這張圖片感到苦惱的朋友，
02:31
I will add somebody for you.
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我要給你們加上一顆。
02:33
(Laughter)
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（笑）
02:34
Courtesy of New Horizons,
we're including Pluto.
we're including Pluto.
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我們尊重“新視野號"，所以連冥王星也算上。
02:38
And the thing here is,
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我們現在討論的是：
02:39
for the purposes of this talk
and atmospheric escape,
and atmospheric escape,
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為了關於“大氣逃離”的研究課題，
02:42
Pluto is a planet in my mind,
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我認為冥王星屬於行星。
02:44
in the same way that planets
around other stars that we can't see
around other stars that we can't see
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同樣的，在我們看不見的恒星周圍
02:48
are also planets.
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公轉的行星都應該被稱作“行星”。
02:49
So fundamental characteristics of planets
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因此，行星的基本特徵
02:52
include the fact that they are bodies
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包括他們受萬有引力吸引而凝聚成一體
02:55
that are bound together by gravity.
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的這個事實。
02:57
So it's a lot of material
just stuck together
just stuck together
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這股吸引力令很多物質
03:00
with this attractive force.
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凝聚在一起。
03:02
And these bodies are so big
and have so much gravity.
and have so much gravity.
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因為這些行星體積巨大而且引力很強，
03:05
That's why they're round.
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所以它們是球體狀。
03:06
So when you look at all of these,
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所以當你看到圖中所示的所有星球，
03:08
including Pluto,
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包括冥王星，
03:09
they're round.
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它們都是球體。
03:11
So you can see that gravity
is really at play here.
is really at play here.
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萬有引力是一個很重要的因素。
03:13
But another fundamental
characteristic about planets
characteristic about planets
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行星的另一個基本特征
03:17
is what you don't see here,
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是你在這個圖裏沒有看到的，
03:18
and that's the star, the Sun,
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那就是我們的恒星——太陽。
03:21
that all of the planets
in the solar system are orbiting around.
in the solar system are orbiting around.
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太陽系中所有行星都圍繞著太陽公轉，
03:25
And that's fundamentally driving
atmospheric escape.
atmospheric escape.
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這也是“大氣逃離”現象的基本原因。
03:29
The reason that fundamentally stars
drive atmospheric escape from planets
drive atmospheric escape from planets
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恒星造成大氣從行星中逃離是因為
03:35
is because stars offer planets
particles and light and heat
particles and light and heat
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恒星為行星提供的微粒、光、和熱
03:40
that can cause the atmospheres to go away.
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會促使大氣逃離。
03:43
So if you think of a hot-air balloon,
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你可以想象一個熱氣球，
03:45
or you look at this picture
of lanterns in Thailand at a festival,
of lanterns in Thailand at a festival,
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或者看看這幅泰國水燈節的照片，
03:49
you can see that hot air
can propel gasses upward.
can propel gasses upward.
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你會見到熱空氣可以驅使氣體上升。
03:53
And if you have enough energy and heating,
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如果能量和熱量充足，
03:55
which our Sun does,
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像太陽那樣，
03:56
that gas, which is so light
and only bound by gravity,
and only bound by gravity,
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那麽質量輕而且受到引力吸引的氣體
04:00
it can escape into space.
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就會逃離進入宇宙，
04:03
And so this is what's actually
causing atmospheric escape
causing atmospheric escape
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造成“大氣逃離”
04:07
here on Earth and also on other planets --
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不僅在地球，而且在其他行星上，
04:10
that interplay
between heating from the star
between heating from the star
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這互相作用都因恒星給予的熱量
04:13
and overcoming the force
of gravity on the planet.
of gravity on the planet.
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和掙脫行星自身的引力而產生。
04:17
So I've told you that it happens
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我曾經提到過：
04:18
at the rate of 400 pounds
a minute for hydrogen
a minute for hydrogen
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氣體逃離的速度是每分鐘四百磅的氫氣
04:22
and almost seven pounds for helium.
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和將近七磅的氦氣，
04:25
But what does that look like?
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但這現象看起來是什麽樣子的呢？
04:26
Well, even in the '80s,
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從八十年代開始，
04:28
we took pictures of the Earth
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美國國家航空航天局使用
04:30
in the ultraviolet
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動態探測器飛船
04:31
using NASA's Dynamic Explorer spacecraft.
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來為地球拍攝紫外線照片。
04:34
So these two images of the Earth
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這兩張照片告訴你
04:36
show you what that glow
of escaping hydrogen looks like,
of escaping hydrogen looks like,
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氫氣逃離時的光是什麽樣的——
04:40
shown in red.
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是紅色的那部分。
04:41
And you can also see other features
like oxygen and nitrogen
like oxygen and nitrogen
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你也可以看到其他部分：
04:45
in that white glimmer
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氧氣和氮氣是白色的、
04:46
in the circle showing you the auroras
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發亮的圓圈的那部分。
04:49
and also some wisps around the tropics.
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還有回歸線附近的小束光線。
04:52
So these are pictures
that conclusively show us
that conclusively show us
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所以總結來看，
04:55
that our atmosphere isn't just
tightly bound to us here on Earth
tightly bound to us here on Earth
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我們的大氣層並不是只與地球緊密相連的，
04:58
but it's actually
reaching out far into space,
reaching out far into space,
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它們用，我會說是驚人的速度，
05:02
and at an alarming rate, I might add.
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逃離到宇宙深處。
05:05
But the Earth is not alone
in undergoing atmospheric escape.
in undergoing atmospheric escape.
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但地球並非唯一存在“大氣逃離”現象的行星，
05:08
Mars, our nearest neighbor,
is much smaller than Earth,
is much smaller than Earth,
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我們最近的鄰居火星比地球小得多，
05:12
so it has much less gravity
with which to hold on to its atmosphere.
with which to hold on to its atmosphere.
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所以它對於它的大氣層具有較小的引力。
05:16
And so even though Mars has an atmosphere,
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所以盡管火星有大氣層，
05:18
we can see it's much thinner
than the Earth's.
than the Earth's.
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火星大氣層比地球大氣層薄得多。
05:20
Just look at the surface.
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火星表面的大坑就可以告訴我們：
05:22
You see craters indicating
that it didn't have an atmosphere
that it didn't have an atmosphere
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火星並沒有一層
05:25
that could stop those impacts.
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足以阻止大氣逃離的大氣。
05:27
Also, we see that it's the "red planet,"
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火星被稱為“紅色行星”，
05:30
and atmospheric escape plays a role
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而“大氣逃離”
05:32
in Mars being red.
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是火星呈紅色的原因之一。
05:34
That's because we think
Mars used to have a wetter past,
Mars used to have a wetter past,
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火星原本是濕潤的，
05:38
and when water had enough energy,
it broke up into hydrogen and oxygen,
it broke up into hydrogen and oxygen,
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當水擁有了足夠能量就會分解成氫氣和氧氣，
05:42
and hydrogen being so light,
it escaped into space,
it escaped into space,
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質量很輕的氫氣逃離了火星，
05:46
and the oxygen that was left
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剩下來的氧氣
05:48
oxidized or rusted the ground,
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氧化了土地，
05:50
making that familiar
rusty red color that we see.
rusty red color that we see.
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使土地變成我們所看到的生銹的紅色。
05:54
So it's fine to look at pictures of Mars
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看到火星的照片，
05:56
and say that atmospheric escape
probably happened,
probably happened,
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我們就可以推斷“大氣逃離”現象的存在。
05:59
but NASA has a probe that's currently
at Mars called the MAVEN satellite,
at Mars called the MAVEN satellite,
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美國國家航空航天局在火星上放置的MAVEN衛星，
06:03
and its actual job
is to study atmospheric escape.
is to study atmospheric escape.
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它的實際任務就是研究“大氣逃離”現象。
06:07
It's the Mars Atmosphere
and Volatile Evolution spacecraft.
and Volatile Evolution spacecraft.
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MAVEN是“火星大氣和不穩定的演變”的縮寫。
06:11
And results from it have already
shown pictures very similar
shown pictures very similar
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它發現火星的“大氣逃離”現象
06:15
to what you've seen here on Earth.
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與地球上發生的很相似。
06:17
We've long known that Mars
was losing its atmosphere,
was losing its atmosphere,
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我們一直知道火星正在失去它的大氣，
06:19
but we have some stunning pictures.
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但讓我們來看看令人震驚的照片。
06:21
Here, for example,
you can see in the red circle
you can see in the red circle
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比方說這裏，你可以看到紅色的圓圈
06:24
is the size of Mars,
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代表火星的大小，
06:26
and in blue you can see the hydrogen
escaping away from the planet.
escaping away from the planet.
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藍色的部分代表逃離火星的氫氣，
06:30
So it's reaching out more than 10 times
the size of the planet,
the size of the planet,
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而這塊藍色的區域是火星大小的十倍，
06:34
far enough away that it's
no longer bound to that planet.
no longer bound to that planet.
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足以證明它們已經不再受到火星引力的吸引，
06:36
It's escaping off into space.
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而是逃離進入了宇宙。
06:38
And this helps us confirm ideas,
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這幫助我們證實了
06:41
like why Mars is red,
from that lost hydrogen.
from that lost hydrogen.
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火星呈紅色的原因是消失的氫氣。
06:44
But hydrogen isn't
the only gas that's lost.
the only gas that's lost.
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但氫氣並非唯一逃離的氣體，
06:47
I mentioned helium on Earth
and some oxygen and nitrogen,
and some oxygen and nitrogen,
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還有我之前提到地球上的氦氣、氧氣、和氮氣。
06:50
and from MAVEN we can also look
at the oxygen being lost from Mars.
at the oxygen being lost from Mars.
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我們還可以通過MAVEN衛星了解火星上消失的氧氣。
06:54
And you can see
that because oxygen is heavier,
that because oxygen is heavier,
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你可以看到，因為氧氣質量重，
06:56
it can't get as far as the hydrogen,
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它們不能像氫氣一樣逃離得那麽遠，
06:59
but it's still escaping
away from the planet.
away from the planet.
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但它們仍在逃離火星。
07:01
You don't see it all confined
into that red circle.
into that red circle.
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圖中綠色的部分不局限在紅色的圓圈以內。
07:05
So the fact that we not only see
atmospheric escape on our own planet
atmospheric escape on our own planet
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因此，我們不僅研究地球上的“大氣逃離”現象，
07:09
but we can study it elsewhere
and send spacecraft
and send spacecraft
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還研究其他行星，並且通過發射飛船
07:13
allows us to learn
about the past of planets
about the past of planets
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我們可以得知行星的歷史、
07:16
but also about planets in general
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行星的一般特征、
07:18
and Earth's future.
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以及地球的未來。
07:20
So one way we actually
can learn about the future
can learn about the future
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我們能預測未來的一個途徑，
07:23
is by planets so far away
that we can't see.
that we can't see.
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是通過我們看不見的遙遠行星。
07:27
And I should just note though,
before I go on to that,
before I go on to that,
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在我繼續講下去之前，我要告訴你們的是，
07:30
I'm not going to show you
photos like this of Pluto,
photos like this of Pluto,
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我沒有其他行星的類似圖片，
07:33
which might be disappointing,
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這可能會令你們失望，
07:34
but that's because we don't have them yet.
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这是因为我們還沒能拍攝到這樣的照片。
07:36
But the New Horizons mission
is currently studying atmospheric escape
is currently studying atmospheric escape
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但是“新視野”目前正在研究
07:39
being lost from the planet.
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“大氣逃離”，
07:41
So stay tuned and look out for that.
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所以你們不久之後就能看到。
07:43
But the planets
that I did want to talk about
that I did want to talk about
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我想介紹的行星
07:45
are known as transiting exoplanets.
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叫作“淩日系外行星”。
07:48
So any planet orbiting a star
that's not our Sun
that's not our Sun
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凡是圍繞除太陽外的其他恒星公轉的行星，
07:51
is called an exoplanet,
or extrasolar planet.
or extrasolar planet.
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都被稱為“外行星”或者“太陽系外行星”。
07:54
And these planets that we call transiting
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我們之所以稱它們為“淩”日系外行星，
07:57
have the special feature
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是因為它們的特殊特征：
07:58
that if you look
at that star in the middle,
at that star in the middle,
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你看圖中間的那顆恒星，
08:00
you'll see that actually it's blinking.
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它實際上正在閃爍，
08:03
And the reason that it's blinking
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而它閃爍的原因是
08:04
is because there are planets
that are going past it all the time,
that are going past it all the time,
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一直有行星在圍繞它公轉，
08:09
and it's at special orientation
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而且行星們公轉的特殊方向
08:11
where the planets are blocking
the light from the star
the light from the star
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導致它們擋住了恒星的光芒，
08:13
that allows us to see that light blinking.
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所以我們才能看到閃爍的光芒。
08:16
And by surveying the stars
in the night sky
in the night sky
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通過研究夜空中的星星
08:19
for this blinking motion,
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閃爍的現象，
08:21
we are able to find planets.
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我們就能找到行星。
08:22
This is how we've now been able
to detect over 5,000 planets
to detect over 5,000 planets
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這是我們能夠在銀河系中
找到超過五千顆行星的方法，
08:27
in our own Milky Way,
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08:28
and we know there are
many more out there, like I mentioned.
many more out there, like I mentioned.
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我們也知道還有更多等待被發現的行星存在。
當我們看到恒星的光芒時，
08:31
So when we look at the light
from these stars,
from these stars,
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我們看到的，如我所言，並不是恒星本身，
08:34
what we see, like I said,
is not the planet itself,
is not the planet itself,
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08:37
but you actually see
a dimming of the light
a dimming of the light
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而是瞬間減弱的光，
08:39
that we can record in time.
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我們可以記錄這段時間。
08:41
So the light drops as the planet
decreases in front of the star,
decreases in front of the star,
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當行星公轉到恒星前方時，光線變暗，
08:44
and that's that blinking
that you saw before.
that you saw before.
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這就是我們看到的閃爍的光芒。
08:47
So not only do we detect the planets
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我們不僅能夠發現行星，
08:49
but we can look at this light
in different wavelengths.
in different wavelengths.
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還可以看到光的不同波長。
08:52
So I mentioned looking at the Earth
and Mars in ultraviolet light.
and Mars in ultraviolet light.
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我曾經提到通過紫外線觀測地球和火星，
08:56
If we look at transiting exoplanets
with the Hubble Space Telescope,
with the Hubble Space Telescope,
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如果我們用哈勃望遠鏡觀測“淩日系外行星”，
08:59
we find that in the ultraviolet,
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我們能發現：在紫外線下
09:01
you see much bigger blinking,
much less light from the star,
much less light from the star,
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可以看到更強的閃爍，以及行星經過時
09:05
when the planet is passing in front.
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恒星散發出的更少的光芒。
09:07
And we think this is because you have
an extended atmosphere of hydrogen
an extended atmosphere of hydrogen
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這個現象的原因是：在行星周圍
09:10
all around the planet
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有一層被延伸了的氫氣層，
09:12
that's making it look puffier
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這使得它看上去更厚，
09:13
and thus blocking
more of the light that you see.
more of the light that you see.
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所以擋住了更多的光。
09:16
So using this technique,
we've actually been able to discover
we've actually been able to discover
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利用這個方法，我們已經成功發現了
09:19
a few transiting exoplanets
that are undergoing atmospheric escape.
that are undergoing atmospheric escape.
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一些有著“大氣逃離”現象的“淩日系外行星”，
09:24
And these planets
can be called hot Jupiters,
can be called hot Jupiters,
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它們其中的一些
09:26
for some of the ones we've found.
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被稱為“熱木星”，
09:28
And that's because
they're gas planets like Jupiter,
they're gas planets like Jupiter,
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這是因為它們是類似木星一樣的氣體行星，
09:31
but they're so close to their star,
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但它們離恒星更近，
09:32
about a hundred times closer than Jupiter.
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大約比木星離太陽的距離短一百倍。
09:35
And because there's all this
lightweight gas that's ready to escape,
lightweight gas that's ready to escape,
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由於這些質輕氣體已經準備好要逃離，
09:38
and all this heating from the star,
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加上來自恒星的熱量，
09:40
you have completely catastrophic rates
of atmospheric escape.
of atmospheric escape.
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“大氣逃離”的速度之快是災難性的。
09:44
So unlike our 400 pounds per minute
of hydrogen being lost on Earth,
of hydrogen being lost on Earth,
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不同於地球上每分鐘四百磅氫氣的逃離速度，
09:48
for these planets,
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在這些行星上，
09:50
you're losing 1.3 billion
pounds of hydrogen every minute.
pounds of hydrogen every minute.
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每分鐘有十三億磅氫氣消失。
09:55
So you might think, well,
does this make the planet cease to exist?
does this make the planet cease to exist?
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你可能會問：“大氣逃離”會讓行星滅亡嗎？
09:59
And this is a question
that people wondered
that people wondered
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這是很多人想問的問題。
10:01
when they looked at our solar system,
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因為在我們的太陽系中，
10:03
because planets
closer to the Sun are rocky,
closer to the Sun are rocky,
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離太陽近的行星都是佈滿岩石的，
10:05
and planets further away
are bigger and more gaseous.
are bigger and more gaseous.
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而離太陽遠的行星更大而且有更多氣體。
10:08
Could you have started
with something like Jupiter
with something like Jupiter
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毀滅不會先從離太陽近的木星
10:11
that was actually close to the Sun,
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先開始嗎？
10:13
and get rid of all the gas in it?
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通過把木星上的所有氣體都排盡。
10:14
We now think that if you start
with something like a hot Jupiter,
with something like a hot Jupiter,
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我們認為如果從“熱木星”這類行星開始，
10:17
you actually can't end up
with Mercury or the Earth.
with Mercury or the Earth.
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最後並不能以水星或者地球結束。
10:20
But if you started with something smaller,
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但如果從更小的行星開始，
10:22
it's possible that enough gas
would have gotten away
would have gotten away
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足夠的氣體消失幹凈是有可能的，
10:25
that it would have
significantly impacted it
significantly impacted it
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而那樣會對這顆行星造成巨大的影響，
10:27
and left you with something very different
than what you started with.
than what you started with.
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而且最後的結果可能跟開始時完全不同。
10:31
So all of this sounds sort of general,
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這些聽起來都很籠統，
10:33
and we might think about the solar system,
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我們可能會聯想到太陽系，
10:35
but what does this have to do
with us here on Earth?
with us here on Earth?
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但這和我們的地球有什麽關系？
10:38
Well, in the far future,
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在很遠的未來，
10:40
the Sun is going to get brighter.
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太陽將會變得更亮，
10:42
And as that happens,
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當這樣的情況發生時，
10:43
the heating that we find from the Sun
is going to become very intense.
is going to become very intense.
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太陽散發出的熱量將會劇增。
10:47
In the same way that you see
gas streaming off from a hot Jupiter,
gas streaming off from a hot Jupiter,
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如同我們看到氣體從“熱木星”上逃離那樣，
10:51
gas is going to stream off from the Earth.
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氣體也會從地球上蒸發。
10:54
And so what we can look forward to,
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所以我們能夠預測的，
10:56
or at least prepare for,
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至少能夠有所準備的是：
10:58
is the fact that in the far future,
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地球將在很遠的未來
11:00
the Earth is going to look more like Mars.
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變得如同火星一般。
11:03
Our hydrogen, from water
that is broken down,
that is broken down,
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從水分解出來的氫氣
11:06
is going to escape
into space more rapidly,
into space more rapidly,
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將會以更快的速度逃離地球，
11:08
and we're going to be left
with this dry, reddish planet.
with this dry, reddish planet.
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而留給我們的將是一個幹燥而泛紅的地球。
11:12
So don't fear, it's not
for a few billion years,
for a few billion years,
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別害怕，這離我們還有幾百萬年的時間，
11:15
so there's some time to prepare.
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我們還有足夠的時間準備。
11:17
(Laughter)
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（笑）
11:18
But I wanted you
to be aware of what's going on,
to be aware of what's going on,
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但是我想讓你們知道的是正在發生的事。
11:21
not just in the future,
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“大氣逃離”並不是將發生在未來，
11:22
but atmospheric escape
is happening as we speak.
is happening as we speak.
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而是發生在此時此刻的每分每秒。
11:25
So there's a lot of amazing science
that you hear about happening in space
that you hear about happening in space
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很多奇妙的科學現象發生在宇宙，
11:29
and planets that are far away,
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和離我們遙遠的行星中，
11:31
and we are studying these planets
to learn about these worlds.
to learn about these worlds.
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而我們通過研究這些行星來了解世界。
11:34
But as we learn about Mars
or exoplanets like hot Jupiters,
or exoplanets like hot Jupiters,
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但當我們研究到火星或是“熱木星”那樣的外行星時，
11:38
we find things like atmospheric escape
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我們發現了“大氣逃離”的現象，
11:42
that tell us a lot more
about our planet here on Earth.
about our planet here on Earth.
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這告訴我們更多關於地球的信息。
11:45
So consider that the next time
you think that space is far away.
you think that space is far away.
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所以下次當你認為宇宙離我們很遠時，請別忘了發生在那裏和這裏的事。
11:49
Thank you.
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謝謝。
11:51
(Applause)
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（鼓掌）
ABOUT THE SPEAKER
Anjali Tripathi - AstrophysicistAnjali Tripathi explores planets to uncover the processes that make and destroy them.
Why you should listen
Even though Anjali Tripathi worked on NASA's Mars rovers in high school, the California native never expected to become an astronomer. Unlike the earthquakes she researched early on, astronomy seemed unconnected from daily life. As she has since discovered, exploring distant planets has a lot to do with life itself -- including the fate of the air we breathe. Using some of the most powerful telescopes and supercomputers, Tripathi studies how seemingly permanent planets change over time. She has pioneered the characterization of planet-forming environments and developed computer simulations to trace the 3D structure of planet atmospheres that are shrinking due to evaporation.
A natural teacher, Tripathi makes complex science concepts relevant and easy to understand. She believes that everyone can understand science -- even rocket science. She has partnered with the Smithsonian, Teach for America and others to increase scientific literacy and spread enthusiasm for the subject. Her engaging and humorous talks feature real world connections and unusual props, including a fully functioning Mars Pathfinder rover or full-size solar car.
Tripathi earned degrees in physics and astronomy from M.I.T., the University of Cambridge and Harvard University. Recognized as a promising American leader with a commitment to public service, Tripathi is a 2016-17 White House Fellow.
Anjali Tripathi | Speaker | TED.com