哇!多么美麗的夕陽啊!
Enjoy it while it lasts, the sun won't be aroundforever, you know.
盡情欣賞吧,太陽不會永遠存在的。
You mean, one day the sun will disappear?
你的意思是,有朝一日太陽會消失?
Not exactly disappear, but the sun will eventuallyburn out and die.
不是完全消失,太陽的能量最后會耗盡并枯竭。
Won't that make things really cold down here?
那樣的話,地球就會變得很冷了。
Actually, there won't be any here, here.
實際上,那時地球就不存在了。
When the sun dies,the earth will be destroy too.
沒有了太陽,地球也將毀滅。
Wow, hold on, start from the beginning.
等一下,你從頭開始說。
Okay. Like all stars, the sun is basically a giant nuclear reactor that burns hydrogen tocreateenergy.
好的。像所有的行星一樣,太陽從根本上說,是一個巨型核反應堆,通過燃燒氫氣產生能量。
But like any reactor, the sun needs fuel to keep going.
但是,就像任一反應堆,太陽需要燃料來保持運作。
It's been going strong for around four-point-five billion years, and will probably keep burning forabout five billion more.
它已經良好運作大約45億年了,并且將會持續(xù)燃燒50億年左右。
But then, the fuel will run out?
到那時,燃料就會耗盡。
Exactly. When it does, gravity will cause the sun's core to contract.
是的。當太陽能量耗盡,地心引力會使得太陽核心縮小。
When it contracts the corewill get hotter, which will heat up the sun's upper layers and makethem expand.
縮小地同時溫度變得更得高,這樣就加劇了太陽外層的燃燒并使其膨脹。
The sun will then become what's called a red giant, and its radius will reach just past the orbitof Venus.
太陽就變成了所謂哦紅巨星,它的半徑將會達到以前金星的運行軌道。
Which is bad for us.
那樣會對我們有害。
We'll be burned to a crisp.
我們會被燒成土豆片的。
That's sounds painful.
聽起來很痛苦。
After a few billion years the core will begin to cool and expand.
數(shù)十億年后太陽中心開始冷卻并擴大。
The sun's upper layers will expand and lose material, and eventually the core will cool enoughto become a white dwarf star,and finally a black dwarf.
太陽的上層也將擴大,失去物質重量,最后中心冷卻到一定程度就成了白矮星,最終成黑矮星。
So, we're pretty much doomed.
那時,我們就注定要完蛋了。
Yes, but not for billions of years.
是的。但那是幾十億年以后的事了。
Who knows? By then, human's might been living on anotherplanet.
誰知道呢?到那時,人類也許已經生活在另一個星球上了。