初級 美國腔 1272 分類 收藏
開始影片後,點擊或框選字幕可以立即查詢單字
字庫載入中…
回報字幕錯誤
Hey there!
Welcome to Life Noggin.
You Earthlings are pretty attached to your sun, and for good reason.
It provides light and heat, drives photosynthesis that makes oxygen, and helps generate weather
patterns.
Without it, you wouldn’t exist.
But if the sun is so great, would it be better if there was more of it?
What if the sun has twice the mass it has now?
Too much of a good thing can be a bad thing, and in this case, it would so bad that no
one would survive.
But before I get to that, you have to understand why mass makes a difference.
As you probably know, the sun is a star, and stars come in a variety of masses.
Generally, a star with more mass — more matter packed into it — glows brighter and
hotter than one with less.
The smallest stars can be less than 8 percent the mass of the sun and give off only .01
percent as much energy.
The largest stars can be a hundred times more massive than the sun and emit thousands of
times as much energy.
Compared to these stars, the sun is actually a pretty normal mass.
But that doesn’t make its relationship to Earth any less special.
Many planets are either too close or too far away from their stars to support life.
Earth is in what we call the Goldilocks Zone, or the habitable zone, where it’s just far
enough away from the sun to have the right temperature for life to exist.
And we’re not the only planet like this.
Scientists believe there are billions of Earth-like planets in habitable zones across the Milky
Way!
In fact, in early 2017, NASA announced they’d found seven exoplanets 39 light years away
that might have water, and three of them are in their star’s habitable zone.
But all of them orbit their star closer than Mercury orbits the sun, so… why don’t
they burn up?
Well, distance is only part of the equation.
These planets orbit an ultra-cool, very small dwarf star only 8 percent as massive as the
sun.
It’s also half as cold as the sun and less than one-thousandth as bright.
Being close to this star is the only way the planets could possibly capture enough light
and heat to support life.
If they were farther away, they would be too cold for life to exist.
So, back to your solar system.
If the sun were twice as massive as it is now, Earth would fall out of the habitable
zone… way out.
First off, with more mass, the sun’s luminosity — the amount of energy and brightness it
gives off — would increase exponentially.
To see what might happen to you, let’s look at Sirius A, the brightest star in your sky.
It’s just about twice as massive as the sun but more than 20 times as luminous.
It’s also several thousand degrees hotter — well over 9000 degrees celsius, compared
to 5500 degrees for the sun.
If the sun was that massive and Earth kept the same distance from it, you’d be toast,
maybe literally.
Earth would not just get significantly hotter, but the oceans would boil away, leaving a
vapor cloud that would trap even more heat.
Plus, if the sun doubled in mass, its gravitational pull would increase.
This could change the Earth’s orbit and tidal patterns, possibly making tides stronger.
All of this would not be good for you Earthlings.
I think it’s probably better to appreciate the sun you have now.
Want to know what would happen if the Earth doubled in size?
Check out this video.
Do you think life exists on other planets in these habitable zones?
Let me know in the comment section below.
提示:點選文章或是影片下面的字幕單字,可以直接快速翻譯喔!

載入中…

如果太陽變大了兩倍會怎麼樣?? (What If The Sun Doubled In Mass?)

1272 分類 收藏
Steven Sou 發佈於 2017 年 5 月 11 日

影片簡介

展開內容
講解生動有趣,可以一邊學天文、一邊學英文喔~~

影片學習單字重點

loading
看更多推薦影片

影片討論

載入中…
  1. 1. 單字查詢

    在字幕上選取單字即可即時查詢單字喔!

  2. 2. 單句重複播放

    可重複聽取一句單句,加強聽力!

  3. 3. 使用快速鍵

    使用影片快速鍵,讓學習更有效率!

  4. 4. 關閉語言字幕

    進階版練習可關閉字幕純聽英文哦!

  5. 5. 內嵌播放器

    可以將英文字幕學習播放器內嵌到部落格等地方喔

  6. 6. 展開播放器

    可隱藏右方全文及字典欄位,觀看影片更舒適!

  1. 英文聽力測驗

    挑戰字幕英文聽力測驗!

  1. 點擊展開筆記本讓你看的更舒服

  1. UrbanDictionary 俚語字典整合查詢。一般字典查詢不到你滿意的解譯,不妨使用「俚語字典」,或許會讓你有滿意的答案喔