宇宙（2007）

to swallowing Earth.
随时有被卷入的危险
However, with the right set of circumstances,
然而 在特定的条件下
our planet could be spared.
地球有可能幸免于难
There's a phenomenon called the solar wind that's continuously blowing,
太阳持续不断地形成的太阳风
lifting material from the outer layers of the Sun's atmosphere
带动太阳大气外层的物质
out into interstellar space.
并将它们释放到星际空间
When the Sun begins to expand into the red giant phase,
当太阳进入膨胀的红巨星阶段后
the outer layers of its atmosphere are even more loosely bound than they are now.
其大气外层比现在的大气更为离散
And so the solar wind will be much more prominent.
这样一来太阳风影响范围会更大
The data indicate that if the solar wind blows off
研究数据标明如果太阳风带走
about 30% of the Sun's mass,
太阳质量的百分之三十
its gravitational pull will weaken enough to allow Earth
太阳对地球的引力就会减弱
to move sufficiently outward.
这足以使地球向外♥围♥移♥动♥
If the Sun loses some of its mass,
如果太阳的质量减少了
its gravity gets weaker and
其引力会变弱
the Earth's orbit is gonna get bigger.
地球公转轨道也因而扩大
So if we're lucky,
如果我们运气够好
our orbit will expand out enough that it will miss the expanding Sun
地球的轨道会扩大到太阳的膨胀范围以外
and we won't get incinerated.
从而逃过被燃为灰烬的命运
But Earth won't be completely removed from harm's way.
然而地球无法完全绕开危险
While the Sun might lose mass,
太阳在减少质量的同时
it could also have a tidal interaction with our planet,
与地球之间也会产生潮汐作用力
and this could have sizzling consequences.
这同样会导致地球被炙烤
There are at least two competing effects.
该过程中至少存在两种此消彼长的影响力
Although as the Sun ages,
尽管随着太阳步入老龄阶段
it's losing mass...
其质量会减少
and that means that Earth's orbit gradually drifts away from the Sun,
也就是说地球的轨道会逐渐远离太阳
it's also true that Earth, being pretty close to the surface of the Sun,
但实际上由于地球离太阳表面过近
will raise a tide, a bulge of gas on the Sun.
会使太阳上掀起一波波气浪
And a gravitational interaction between that bulge
而气浪和地球之间的引力相互作用
and the Earth will actually slow down the Earth in its orbit,
会减慢地球的公转速度
causing the Earth to gradually spiral in.
从而使地球逐渐向轨道内侧旋转
So maybe the loss of mass will move us out enough to be safe.
太阳质量的减少可能使地球轨道安全外移
But maybe the tidal forces will spiral us in enough
但产生的潮汐力可能把地球向内牵引
that we'll be engulfed and the Earth will be incinerated.
以致地球可能被太阳吞没并燃为灰烬
And if you come back in 5 or 6 billion years,
等五六十亿年后再回来看
you'll know which one wins out.
就能知道鹿死谁手了
Earth just might get lucky.
地球可能是幸运的
An international team of astronomers discovered a planet
一个国际天文学家小组发现了太阳系外的
outside our solar system that survived the death of its home star.
一颗行星逃过了其主星死亡带来的厄运
The exoplanet is at least three times as massive as Jupiter
这颗系外行星的体积至少是木星的三倍
and orbits the star dubbed 391 Pegasi,
并绕着恒星391佩贾斯公转
which is about the same mass as our Sun.
该恒星与太阳体积相当
Some exoplanets clearly do survive
有些系外行星经历了
through the red giant stage.
其主星的红巨星阶段后仍能存在
For example, 391 Pegasi is a star that has an exoplanet around it,
比如391佩贾斯与其系外行星
a planet orbiting it, and that planet is still there.
绕着它公转的这颗行星幸存了下来
Now, it might have a rocky Earth-like core
这颗行星可能和地球一样有岩石核心
and perhaps even an iron central region.
甚至有铁质内核
But we think it's mostly gaseous and liquid.
但我们认为它很可能是气态或液态行星
391 Pegasi and its gas giant planet
391佩贾斯及其巨大的气体行星
have a similar orbital distance from each other
之间的轨道距离和
as Earth does from our Sun,
地球与太阳之间的轨道距离非常相似
which is about 90 million miles.
即约为九千万英里
Astronomers think the exoplanet survived
天文学家们认为这颗系外行星能存活
because its death star lost mass,
是因为已死亡的主星质量的减少
which reduced its gravitational pull on the planet,
导致对该行星的引力作用的减弱
just enough so that it drifted slightly outward.
其程度恰好使行星稍微向外偏离
The planets around 391 Pegasi is likely to be one of these planets
这些绕391佩贾斯公转的行星
that sort of walked the knife edge between
在向外旋转和在被潮汐力作用向内牵引
spiraling outwards and being dragged in by tides.
之间找到了微妙的平衡点
But you would not expect to find a lot of planets
但与主星距离恰到好处的行星
in that particular range of distances.
并不多见
You would expect them to either be completely swallowed
大多数行星要么被主星完全吞没
or have them be much further out.
要么就远远地移开
So it requires a somewhat delicate balance of the two competing forces
因此只有这两种力达到微妙的平衡
to actually enable a planet to survive at that sort of location.
才能使行星移♥动♥到安全范围
So there's one case in which the planet survived.
由此看来 行星的幸存已有先例
The bad news is that in this solar system,
但不幸的是在这类似太阳系的星系里
the planet is really big, larger than Jupiter.
该行星的体积比木星的还要大
And so it probably has a better chance of surviving
因此它的幸存几率要比
than a small planet like the Earth would.
地球这样的小行星大得多
It appears that stellar winds
391佩贾斯产生的恒星风
and thermal pulsations produced by 391 Pegasi
和热力脉冲似乎
pulled atmospheric material from the outer layers of the exoplanet
使系外行星的大气表层物质在引力作用下
and hurled it into space.
被释放到太空中
However, the gas giant planet survived
然而这颗气体巨星仍幸存了下来
because it could afford to lose a lot of mass.
因所散失的质量在其可承受范围之内
We can speculate that it may have lost
可推测该行星所散失物质的质量
one or more Earth masses of material.
相当于不止一个地球
And of course, if the Earth lost that much material,
很显然 如果地球散失了相当的质量
it wouldn't be here.
也就不复存在了
Certainly, a Jupiter-sized planet, a gas giant
当然 与木星等大的气体巨星
isn't inhabitable by people.
并不适合人类居住
But it's still intriguing that if the Sun went to the red giant phase,
但令人感兴趣的是当太阳进入红巨星阶段
it's possible that Jupiter would survive.
木星将可能是幸存下来的行星
The continued existence of the gas giant planet
绕391佩贾斯公转的气体巨星
orbiting 391 Pegasi doesn't provide conclusive evidence one way or the other,
的存在无论如何都不能有力地说明
whether Earth will survive the death of our Sun.
地球能否在太阳的死亡后幸存下来
But one thing seems certain.
但可以肯定的是
Long before our Sun becomes a red giant,
早在太阳成为红巨星之前
our planet will no longer be hospitable for Earth-type life.
我们的星球已不再适合地球生命的生存
Any future civilizations will need to relocate,
未来的文明都必须在人间炼狱
and billions of years before the impending inferno.
形成前数十亿年迁徙到其他星球
About a billion years from now,
今后大约十亿年的时间里
if viewers were around, I'd recommend that you move to Mars.
假如你们还活着 我建议你们移居火星
Mars, instead of being too cool like it is now,
那时火星已经不像现在这么冷了
would probably have a somewhat more favorable temperature.
那里的气温可能会更为适宜
If there is water underground in Mars,
如果火星地底有水
and we don't really know one way or the other for certain yet,
且我们掌握了现在仍未知的某种技术
maybe you could use some of that water
你们就可以好好利用这些水
and you might have a comfortable retirement on the planet Mars.
并在火星上安享晚年了
But the move to Mars wouldn't be simple.
要移居火星并非易事
The red planet would be warmer than it is today,
未来这颗红色行星虽会比现在更为温暖
but it would still be missing a few of life's necessities.
却仍缺少某些生命的必要元素
You have to create an atmosphere.
首先要创造适宜的大气环境
You have to have pretty high pressures in order to
接下来要制♥造♥足够的压力
have molten water on the surface.
以使地面上形成液态水
You need to somehow generate oxygen.
还要制♥造♥氧气
Just because a planet or a moon is in the habitable zone
我们说某颗行星或卫星是人类的可居住区
doesn't mean that it's already habitable.
并不代表它们已可供居住
If you were a strategic planner,
如果你是名策略规划师
you would encourage the growth of plant life on Mars
你可能会设想十亿年后
a billion years in the future.
在火星上种植植物
You would generate oxygen,
以此制♥造♥氧气
and you'd make that planet more hospitable for us.
使火星更适合人类居住
Perhaps, a little egotistically, we call that terraforming,
也许稍微自负点说 我们称之为地球化
That we could form another planet in the shape of Terra or the Earth.
我们能够创造出另一个类似地球的行星
I hope we're here to do that.
我希望我们可以着手于此
Even if an advanced society manages to colonize Mars,
即使高度文明的社会成功殖民到火星上
This new home will be temporary.
这个新家也只会是暂时的
The Sun will continue to become brighter and bigger,
太阳会继续变得更大更亮
Pushing the habitable zone ever farther out.
将宜居地带不断向外推出
During the red giant phase,
在红巨星阶段
Earthlings will have to move again,
地球人又得搬家了
Perhaps to the water-rich moons of Jupiter or Saturn,
也许搬到木星或者土星某个含水量多的卫星上
But with every new location,
但每到一个新地方
There will be more obstacles.
都将遇到更多的艰难险阻
Near the end of the Sun's red giant stage,
到太阳的红巨星阶段临近结束时
It will rapidly be growing much brighter and much bigger
它会急剧变大变亮