下載App 希平方
攻其不背
App 開放下載中
下載App 希平方
攻其不背
App 開放下載中
IE版本不足
您的瀏覽器停止支援了😢使用最新 Edge 瀏覽器或點選連結下載 Google Chrome 瀏覽器 前往下載

免費註冊
! 這組帳號已經註冊過了
Email 帳號
密碼請填入 6 位數以上密碼
已經有帳號了?
忘記密碼
! 這組帳號已經註冊過了
您的 Email
請輸入您註冊時填寫的 Email,
我們將會寄送設定新密碼的連結給您。
寄信了!請到信箱打開密碼連結信
密碼信已寄至
沒有收到信嗎?
如果您尚未收到信,請前往垃圾郵件查看,謝謝!

恭喜您註冊成功!

查看會員功能

註冊未完成

《HOPE English 希平方》服務條款關於個人資料收集與使用之規定

隱私權政策
上次更新日期:2014-12-30

希平方 為一英文學習平台,我們每天固定上傳優質且豐富的影片內容,讓您不但能以有趣的方式學習英文,還能增加內涵,豐富知識。我們非常注重您的隱私,以下說明為當您使用我們平台時,我們如何收集、使用、揭露、轉移及儲存你的資料。請您花一些時間熟讀我們的隱私權做法,我們歡迎您的任何疑問或意見,提供我們將產品、服務、內容、廣告做得更好。

本政策涵蓋的內容包括:希平方學英文 如何處理蒐集或收到的個人資料。
本隱私權保護政策只適用於: 希平方學英文 平台,不適用於非 希平方學英文 平台所有或控制的公司,也不適用於非 希平方學英文 僱用或管理之人。

個人資料的收集與使用
當您註冊 希平方學英文 平台時,我們會詢問您姓名、電子郵件、出生日期、職位、行業及個人興趣等資料。在您註冊完 希平方學英文 帳號並登入我們的服務後,我們就能辨認您的身分,讓您使用更完整的服務,或參加相關宣傳、優惠及贈獎活動。希平方學英文 也可能從商業夥伴或其他公司處取得您的個人資料,並將這些資料與 希平方學英文 所擁有的您的個人資料相結合。

我們所收集的個人資料, 將用於通知您有關 希平方學英文 最新產品公告、軟體更新,以及即將發生的事件,也可用以協助改進我們的服務。

我們也可能使用個人資料為內部用途。例如:稽核、資料分析、研究等,以改進 希平方公司 產品、服務及客戶溝通。

瀏覽資料的收集與使用
希平方學英文 自動接收並記錄您電腦和瀏覽器上的資料,包括 IP 位址、希平方學英文 cookie 中的資料、軟體和硬體屬性以及您瀏覽的網頁紀錄。

隱私權政策修訂
我們會不定時修正與變更《隱私權政策》,不會在未經您明確同意的情況下,縮減本《隱私權政策》賦予您的權利。隱私權政策變更時一律會在本頁發佈;如果屬於重大變更,我們會提供更明顯的通知 (包括某些服務會以電子郵件通知隱私權政策的變更)。我們還會將本《隱私權政策》的舊版加以封存,方便您回顧。

服務條款
歡迎您加入看 ”希平方學英文”
上次更新日期:2013-09-09

歡迎您加入看 ”希平方學英文”
感謝您使用我們的產品和服務(以下簡稱「本服務」),本服務是由 希平方學英文 所提供。
本服務條款訂立的目的,是為了保護會員以及所有使用者(以下稱會員)的權益,並構成會員與本服務提供者之間的契約,在使用者完成註冊手續前,應詳細閱讀本服務條款之全部條文,一旦您按下「註冊」按鈕,即表示您已知悉、並完全同意本服務條款的所有約定。如您是法律上之無行為能力人或限制行為能力人(如未滿二十歲之未成年人),則您在加入會員前,請將本服務條款交由您的法定代理人(如父母、輔助人或監護人)閱讀,並得到其同意,您才可註冊及使用 希平方學英文 所提供之會員服務。當您開始使用 希平方學英文 所提供之會員服務時,則表示您的法定代理人(如父母、輔助人或監護人)已經閱讀、了解並同意本服務條款。 我們可能會修改本條款或適用於本服務之任何額外條款,以(例如)反映法律之變更或本服務之變動。您應定期查閱本條款內容。這些條款如有修訂,我們會在本網頁發佈通知。變更不會回溯適用,並將於公布變更起十四天或更長時間後方始生效。不過,針對本服務新功能的變更,或基於法律理由而為之變更,將立即生效。如果您不同意本服務之修訂條款,則請停止使用該本服務。

第三人網站的連結 本服務或協力廠商可能會提供連結至其他網站或網路資源的連結。您可能會因此連結至其他業者經營的網站,但不表示希平方學英文與該等業者有任何關係。其他業者經營的網站均由各該業者自行負責,不屬希平方學英文控制及負責範圍之內。

兒童及青少年之保護 兒童及青少年上網已經成為無可避免之趨勢,使用網際網路獲取知識更可以培養子女的成熟度與競爭能力。然而網路上的確存有不適宜兒童及青少年接受的訊息,例如色情與暴力的訊息,兒童及青少年有可能因此受到心靈與肉體上的傷害。因此,為確保兒童及青少年使用網路的安全,並避免隱私權受到侵犯,家長(或監護人)應先檢閱各該網站是否有保護個人資料的「隱私權政策」,再決定是否同意提出相關的個人資料;並應持續叮嚀兒童及青少年不可洩漏自己或家人的任何資料(包括姓名、地址、電話、電子郵件信箱、照片、信用卡號等)給任何人。

為了維護 希平方學英文 網站安全,我們需要您的協助:

您承諾絕不為任何非法目的或以任何非法方式使用本服務,並承諾遵守中華民國相關法規及一切使用網際網路之國際慣例。您若係中華民國以外之使用者,並同意遵守所屬國家或地域之法令。您同意並保證不得利用本服務從事侵害他人權益或違法之行為,包括但不限於:
A. 侵害他人名譽、隱私權、營業秘密、商標權、著作權、專利權、其他智慧財產權及其他權利;
B. 違反依法律或契約所應負之保密義務;
C. 冒用他人名義使用本服務;
D. 上載、張貼、傳輸或散佈任何含有電腦病毒或任何對電腦軟、硬體產生中斷、破壞或限制功能之程式碼之資料;
E. 干擾或中斷本服務或伺服器或連結本服務之網路,或不遵守連結至本服務之相關需求、程序、政策或規則等,包括但不限於:使用任何設備、軟體或刻意規避看 希平方學英文 - 看 YouTube 學英文 之排除自動搜尋之標頭 (robot exclusion headers);

服務中斷或暫停
本公司將以合理之方式及技術,維護會員服務之正常運作,但有時仍會有無法預期的因素導致服務中斷或故障等現象,可能將造成您使用上的不便、資料喪失、錯誤、遭人篡改或其他經濟上損失等情形。建議您於使用本服務時宜自行採取防護措施。 希平方學英文 對於您因使用(或無法使用)本服務而造成的損害,除故意或重大過失外,不負任何賠償責任。

版權宣告
上次更新日期:2013-09-16

希平方學英文 內所有資料之著作權、所有權與智慧財產權,包括翻譯內容、程式與軟體均為 希平方學英文 所有,須經希平方學英文同意合法才得以使用。
希平方學英文歡迎你分享網站連結、單字、片語、佳句,使用時須標明出處,並遵守下列原則:

  • 禁止用於獲取個人或團體利益,或從事未經 希平方學英文 事前授權的商業行為
  • 禁止用於政黨或政治宣傳,或暗示有支持某位候選人
  • 禁止用於非希平方學英文認可的產品或政策建議
  • 禁止公佈或傳送任何誹謗、侮辱、具威脅性、攻擊性、不雅、猥褻、不實、色情、暴力、違反公共秩序或善良風俗或其他不法之文字、圖片或任何形式的檔案
  • 禁止侵害或毀損希平方學英文或他人名譽、隱私權、營業秘密、商標權、著作權、專利權、其他智慧財產權及其他權利、違反法律或契約所應付支保密義務
  • 嚴禁謊稱希平方學英文辦公室、職員、代理人或發言人的言論背書,或作為募款的用途

網站連結
歡迎您分享 希平方學英文 網站連結,與您的朋友一起學習英文。

抱歉傳送失敗!

不明原因問題造成傳送失敗,請儘速與我們聯繫!
希平方 x ICRT

「Sara Seager:探索太陽系外星球」- The Search for Planets beyond Our Solar System

觀看次數:2509  • 

框選或點兩下字幕可以直接查字典喔!

I'm here to tell you about the real search for alien life. Not little green humanoids arriving in shiny UFOs, although that would be nice. But it's the search for planets orbiting stars far away.

Every star in our sky is a sun. And if our sun has planets—Mercury, Venus, Earth, Mars, etc., surely those other stars should have planets also, and they do. And in the last two decades, astronomers have found thousands of exoplanets.

Our night sky is literally teeming with exoplanets. We know, statistically speaking, that every star has at least one planet. And in the search for planets, and in the future, planets that might be like Earth, we're able to help address some of the most amazing and mysterious questions that have faced humankind for centuries. Why are we here? Why does our universe exist? How did Earth form and evolve? How and why did life originate and populate our planet? The second question that we often think about is: Are we alone? Is there life out there? Who is out there? You know, this question has been around for thousands of years, since at least the time of the Greek philosophers. But I'm here to tell you just how close we're getting to finding out the answer to this question. It's the first time in human history that this really is within reach for us.

Now when I think about the possibilities for life out there, I think of the fact that our sun is but one of many stars. This is a photograph of a real galaxy, we think our Milky Way looks like this galaxy. It's a collection of bound stars. But our milky way is one of hundreds of billions of stars and our galaxy is one of upwards of hundreds of billions of galaxies. Knowing that small planets are very common, you can just do the math. And there are just so many stars and so many planets out there, that surely, there must be life somewhere out there. Well, the biologists get furious with me for saying that, because we have absolutely no evidence for life beyond Earth yet.

Well, if we were able to look at our galaxy from the outside and zoom in to where our sun is, we see a real map of the stars. And the highlighted stars are those with known exoplanets. This is really just the tip of the iceberg. Here, this animation is zooming in onto our solar system. And you'll see here the planets as well as some spacecraft that are also orbiting our sun. Now if we can imagine going to the West Coast of North America, and looking out at the night sky, here's what we'd see on a spring night. And you can see the constellations overlaid and again, so many stars with planets. There's a special patch of the sky where we have thousands of planets.

This is where the Kepler Space Telescope focused for many years. Let's zoom in and look at one of the favorite exoplanets. This star is called Kepler-186f. It's a system of about five planets. And by the way, most of these exoplanets, we don't know too much about. We know their size, and their orbit and things like that. But there's a very special planet here called Kepler-186f. This planet is in a zone that is not too far from the star, so that the temperature may be just right for life. Here, the artist's conception is just zooming in and showing you what that planet might be like.

So, many people have this romantic notion of astronomers going to the telescope on a lonely mountaintop and looking at the spectacular night sky through a big telescope. But actually, we just work on our computers like everyone else, and we get our data by email or downloading from a database. So instead of coming here to tell you about the somewhat tedious nature of the data and data analysis and the complex computer models we make, I have a different way to try to explain to you some of the things that we're thinking about exoplanets.

Here's a travel poster: "Kepler-186f: Where the grass is always redder on the other side." That's because Kepler-186f orbits a red star, and we're just speculating that perhaps the plants there, if there is vegetation that does photosynthesis, it has different pigments and looks red. "Enjoy the gravity on HD 40307g, a Super-Earth." This planet is more massive than Earth and has a higher surface gravity. "Relax on Kepler-16b, where your shadow always has company." We know of a dozen planets that orbit two stars, and there's likely many more out there. If we could visit one of those planets, you literally would see two sunsets and have two shadows. So actually, science fiction got some things right. Tatooine from Star Wars. And I have a couple of other favorite exoplanets to tell you about. This one is Kepler-10b, it's a hot, hot planet. It orbits over 50 times closer to its star than our Earth does to our sun. And actually, it's so hot, we can't visit any of these planets, but if we could, we would melt long before we got there. We think the surface is hot enough to melt rock and has liquid lava lakes.

Gliese 1214b. This planet, we know the mass and the size and it has a fairly low density. It's somewhat warm. We actually don't know really anything about this planet, but one possibility is that it's a water world, like a scaled-up version of one of Jupiter's icy moons that might be 50 percent water by mass. And in this case, it would have a thick steam atmosphere overlaying an ocean, not of liquid water, but of an exotic form of water, a superfluid—not quite a gas, not quite a liquid. And under that wouldn't be rock, but a form of high-pressure ice, like ice IX.

So out of all these planets out there, and the variety is just simply astonishing, we mostly want to find the planets that are Goldilocks planets, we call them. Not too big, not too small, not too hot, not too cold—but just right for life. But to do that, we'd have to be able to look at the planet's atmosphere, because the atmosphere acts like a blanket trapping heat—the greenhouse effect. We have to be able to assess the greenhouse gases on other planets. Well, science fiction got some things wrong. The Star Trek Enterprise had to travel vast distances at incredible speeds to orbit other planets so that First Officer Spock could analyze the atmosphere to see if the planet was habitable or if there were life forms there.

Well, we don't need to travel at warp speeds to see other planet atmospheres, although I don't want to dissuade any budding engineers from figuring out how to do that. We actually can and do study planet atmospheres from here, from Earth orbit. This is a picture, a photograph of the Hubble Space Telescope taken by the shuttle Atlantis as it was departing after the last human space flight to Hubble. They installed a new camera, actually, that we use for exoplanet atmospheres. And so far, we've been able to study dozens of exoplanet atmospheres, about six of them in great detail. But those are not small planets like Earth. They're big, hot planets that are easy to see. We're not ready, we don't have the right technology yet to study small exoplanets. But nevertheless, I wanted to try to explain to you how we study exoplanet atmospheres.

I want you to imagine, for a moment, a rainbow. And if we could look at this rainbow closely, we would see that some dark lines are missing. And here's our sun, the white light of our sun split up, not by raindrops, but by a spectrograph. And you can see all these dark, vertical lines. Some are very narrow, some are wide, some are shaded at the edges. And this is actually how astronomers have studied objects in the heavens, literally, for over a century. So here, each different atom and molecule has a special set of lines, a fingerprint, if you will. And that's how we study exoplanet atmospheres. And I'll just never forget when I started working on exoplanet atmospheres 20 years ago, how many people told me, "This will never happen. We'll never be able to study them. Why are you bothering?" And that's why I'm pleased to tell you about all the atmospheres studied now, and this is really a field of its own. So when it comes to other planets, other Earths, in the future when we can observe them, what kind of gases would we be looking for? Well, you know, our own Earth has oxygen in the atmosphere to 20 percent by volume. That's a lot of oxygen. But without plants and photosynthetic life, there would be no oxygen, virtually no oxygen in our atmosphere. So oxygen is here because of life. And our goal then is to look for gases in other planet atmospheres, gases that don't belong, that we might be able to attribute to life. But which molecules should we search for? I actually told you how diverse exoplanets are. We expect that to continue in the future when we find other Earths.

And that's one of the main things I'm working on now, I have a theory about this. It reminds me that nearly every day, I receive an email or emails from someone with a crazy theory about physics of gravityor cosmology or some such. So, please don't email me one of your crazy theories. Well, I had my own crazy theory. But, who does the MIT professor go to? Well, I emailed a Nobel Laureate in Physiology or Medicine and he said, "Sure, come and talk to me." So I brought my two biochemistry friends and we went to talk to him about our crazy theory. And that theory was that life produces all small molecules, so many molecules. Like, everything I could think of, but not being a chemist. Think about it: carbon dioxide, carbon monoxide, molecular hydrogen, molecular nitrogen, methane, methyl chloride—so many gases. They also exist for other reasons, but just life even produces ozone. So we go to talk to him about this, and immediately, he shot down the theory. He found an example that didn't exist. So, we went back to the drawing board and we think we have found something very interesting in another field.

But back to exoplanets, the point is that life produces so many different types of gases, literally thousands of gases. And so what we're doing now is just trying to figure out on which types of exoplanets, which gases could be attributed to life. And so when it comes time when we find gases in exoplanet atmospheres that we won't know if they're being produced by intelligent aliens or by trees, or a swamp, or even just by simple, single-celled microbial life.

So working on the models and thinking about biochemistry, it's all well and good. But a really big challenge ahead of us is: how? How are we going to find these planets? There are actually many ways to find planets, several different ways. But the one that I'm most focused on is how can we open a gatewayso that in the future, we can find hundreds of Earths. We have a real shot at finding signs of life. And actually, I just finished leading a two-year project in this very special phase of a concept we call the starshade. And the starshade is a very specially shaped screen and the goal is to fly that starshade so it blocks out the light of a star so that the telescope can see the planets directly. Here, you can see myself and two team members holding up one small part of the starshade. It's shaped like a giant flower, and this is one of the prototype petals. The concept is that a starshade and telescope could launch together, with the petals unfurling from the stowed position. The central truss would expand, with the petals snapping into place. Now, this has to be made very precisely, literally, the petals to microns and they have to deploy to millimeters. And this whole structure would have to fly tens of thousands of kilometers away from the telescope. It's about tens of meters in diameter. And the goal is to block out the starlight to incredible precision so that we'd be able to see the planets directly. And it has to be a very special shape, because of the physics of defraction. Now this is a real project that we worked on, literally, you would not believe how hard. Just so you believe it's not just in movie format, here's a real photograph of a second-generation starshade deployment test bed in the lab. And in this case, I just wanted you to know that that central truss has heritage left over from large radio deployables in space.

So after all of that hard work where we try to think of all the crazy gases that might be out there, and we build the very complicated space telescopes that might be out there, what are we going to find? Well, in the best case, we will find an image of another exo-Earth. Here is Earth as a pale blue dot. And this is actually a real photograph of Earth taken by the Voyager 1 spacecraft, four billion miles away. And that red light is just scattered light in the camera optics.

But what's so awesome to consider is that if there are intelligent aliens orbiting on a planet around a star near to us and they build complicated space telescopes of the kind that we're trying to build, all they'll see is this pale blue dot, a pinprick of light. And so sometimes, when I pause to think about my professional struggle and huge ambition, it's hard to think about that in contrast to the vastness of the universe. But nonetheless, I am devoting the rest of my life to finding another Earth.

And I can guarantee

that in the next generation of space telescopes, in the second generation, we will have the capability to find and identity other Earths. And the capability to split up the starlight so that we can look for gases and assess the greenhouse gases in the atmosphere, estimate the surface temperature, and look for signs of life.

But there's more. In this case of searching for other planets like Earth, we are making a new kind of map of the nearby stars and of the planets orbiting them, including [planets] that actually might be inhabitable by humans.

And so I envision that our descendants, hundreds of years from now, will embark on an interstellar journey to other worlds. And they will look back at all of us as the generation who first found the Earth-like worlds.

Thank you.

And I give you, for a question, Rosetta Mission Manager Fred Jansen.

You mentioned halfway through that the technology to actually look at the spectrum of an exoplanet like Earth is not there yet. When do you expect this will be there, and what's needed?

Actually, what we expect is what we call our next-generation Hubble telescope. And this is called the James Webb Space Telescope, and that will launch in 2018, and that's what we're going to do, we're going to look at a special kind of planet called transient exoplanets, and that will be our first shot at studying small planets for gases that might indicate the planet is habitable.

I'm going to ask you one follow-up question, too, Sara, as the generalist. So I am really struck by the notion in your career of the opposition you faced, that when you began thinking about exoplanets, there was extreme skepticism in the scientific community that they existed, and you proved them wrong. What did it take to take that on?

Well, the thing is that as scientists, we're supposed to be skeptical, because our job to make sure that what the other person is saying actually makes sense or not. But being a scientist, I think you've seen it from this session, it's like being an explorer. You have this immense curiosity, this stubbornness, this sort of resolute will that you will go forward no matter what other people say.

I love that. Thank you, Sara.

播放本句

登入使用學習功能

使用Email登入

HOPE English 播放器使用小提示

  • 功能簡介

    單句重覆、重複上一句、重複下一句:以句子為單位重覆播放,單句重覆鍵顯示綠色時為重覆播放狀態;顯示白色時為正常播放狀態。按重複上一句、重複下一句時就會自動重覆播放該句。
    收錄佳句:點擊可增減想收藏的句子。

    中、英文字幕開關:中、英文字幕按鍵為綠色為開啟,灰色為關閉。鼓勵大家搞懂每一句的內容以後,關上字幕聽聽看,會發現自己好像在聽中文說故事一樣,會很有成就感喔!
    收錄單字:框選英文單字可以收藏不會的單字。
  • 分享
    如果您有收錄很優秀的句子時,可以分享佳句給大家,一同看佳句學英文!