Anjali Tripathi: Why Earth may someday look like Mars
アンジャリ・トゥリパーティー: いずれは地球も火星のようになるその理由
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.
at the stars at night,
is what you can't see,
目には見えない星が もっとあるのです
or almost every star,
1つや2つはあると
we tend to think of faraway things
私たちは遥か彼方にある
想像しがちですが
that are amazing about Earth
驚くべき現象があります
to find things that are like that.
幅広く宇宙を探索する中
we're finding amazing things.
about an amazing thing here on Earth.
お話ししたいと思います
and never coming back.
ということです
as the Earth's atmosphere.
that form a thin blue line
ISSから撮ったこの写真に
the International Space Station,
この薄い層のお陰で
from too many impacts,
失われているということは
at least a little bit.
恐るべき話です
is not specific to planet Earth.
to be a planet, if you ask me,
言ってもいいでしょう
but throughout the universe,
about planets themselves.
知る手がかりとなります
about the solar system,
there are eight planets, maybe nine.
9個だと言う人もいるでしょうから
who are stressed by this picture,
そんなあなたの為に
we're including Pluto.
あるので冥王星も並べましょう
and atmospheric escape,
このトークの目的のため
周回する惑星と同じように
around other stars that we can't see
just stuck together
and have so much gravity.
これら全ての惑星を見ると
これら全ての惑星を見ると
is really at play here.
characteristic about planets
in the solar system are orbiting around.
太陽を周回していますが
atmospheric escape.
引き起こしているのです
drive atmospheric escape from planets
起こさせている根本的な原因は
particles and light and heat
粒子や光や熱が
流出させているからです
of lanterns in Thailand at a festival,
「コムローイ祭り」の提灯を見ても
can propel gasses upward.
生み出すのが分かります
and only bound by gravity,
非常に軽い気体は
causing atmospheric escape
自己重力に逆らいながら
between heating from the star
大気散逸が起きています
of gravity on the planet.
a minute for hydrogen
水素が約180kg
of escaping hydrogen looks like,
like oxygen and nitrogen
that conclusively show us
tightly bound to us here on Earth
しっかりと包んでいるだけでなく
reaching out far into space,
流出しているということです
起きているのです
in undergoing atmospheric escape.
起こしているのではありません
is much smaller than Earth,
地球よりずっと小さいので
with which to hold on to its atmosphere.
than the Earth's.
that it didn't have an atmosphere
和らげられなかったことを示す
Mars used to have a wetter past,
it broke up into hydrogen and oxygen,
水素と酸素に分解して
it escaped into space,
rusty red color that we see.
思われています
言うのは構わないのですが
probably happened,
at Mars called the MAVEN satellite,
衛星探査機「メイヴン」で
is to study atmospheric escape.
and Volatile Evolution spacecraft.
shown pictures very similar
随分前から分かっていましたが
was losing its atmosphere,
you can see in the red circle
escaping away from the planet.
火星から散逸している水素を示しています
the size of the planet,
その範囲は広がっています
no longer bound to that planet.
もはや火星の大気圏にはなく
水素が無くなったので
from that lost hydrogen.
理論が裏付けられます
the only gas that's lost.
水素だけではありません
and some oxygen and nitrogen,
酸素や窒素も散逸していますが
at the oxygen being lost from Mars.
メイヴンからの記録で見て取れます
that because oxygen is heavier,
away from the planet.
into that red circle.
わけではないのが分かります
atmospheric escape on our own planet
見られる現象ではなく
and send spacecraft
探査機を送り大気散逸を調べると
about the past of planets
知ることができます
can learn about the future
that we can't see.
というのが1つの方法です
before I go on to that,
お見せできません
photos like this of Pluto,
is currently studying atmospheric escape
that I did want to talk about
として知られている
that's not our Sun
周回する惑星です
or extrasolar planet.
「太陽系外惑星」と呼ばれる
at that star in the middle,
that are going past it all the time,
複数の惑星があるからです
the light from the star
in the night sky
to detect over 5,000 planets
もっとあると思っています
many more out there, like I mentioned.
from these stars,
is not the planet itself,
a dimming of the light
decreases in front of the star,
恒星からの光を遮り
that you saw before.
瞬いているように見えるのです
in different wavelengths.
and Mars in ultraviolet light.
紫外線で見ると言いましたが
with the Hubble Space Telescope,
トランジット系外惑星の
much less light from the star,
紫外線はずっと弱くなり
an extended atmosphere of hydrogen
more of the light that you see.
考えています
we've actually been able to discover
大気散逸をしている
that are undergoing atmospheric escape.
発見することが出来ました
幾つかは
can be called hot Jupiters,
呼びたいものです
they're gas planets like Jupiter,
主に気体でできた惑星だからです
恒星にとても近く
百分の1程しかありません
lightweight gas that's ready to escape,
今にも散逸しそうな軽い気体と
of atmospheric escape.
大気散逸が起きています
of hydrogen being lost on Earth,
失っている地球とは雲泥の差で
pounds of hydrogen every minute.
失っているのです
does this make the planet cease to exist?
無くなってしまうのではと
that people wondered
closer to the Sun are rocky,
岩石惑星で
are bigger and more gaseous.
もっと大きく主に気体だからです
with something like Jupiter
太陽が近いので
with something like a hot Jupiter,
ホット・ジュピターみたいな状態だったら
with Mercury or the Earth.
ならないだろうと考えています
would have gotten away
significantly impacted it
than what you started with.
なった可能性はあります
お考えのことかもしれません
with us here on Earth?
どんな関係があるのでしょう
is going to become very intense.
非常に強烈になるとしたなら
gas streaming off from a hot Jupiter,
気体が流出しているように
急速に流出して行きます
と言う現実があるからなのです
that is broken down,
into space more rapidly,
放出され
with this dry, reddish planet.
for a few billion years,
数十億年後の話ですから
to be aware of what's going on,
is happening as we speak.
起きていることに気付いて欲しかったのです
that you hear about happening in space
遥か彼方の惑星について知らせてくれる
今はあります
to learn about these worlds.
これらの惑星を研究しています
or exoplanets like hot Jupiters,
系外惑星を調べる過程で
about our planet here on Earth.
さらに解明されます
you think that space is far away.
感じられる時 この私の話を思い出して下さい
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