Hey there! Welcome to Life Noggin!
大家好！欢迎来到脑洞大开的生命奇想！
Our solar system is pretty weird.
我们的太阳系有点奇怪。
Over the past few decades, scientists have discovered and confirmed over one thousand exoplanets,
过去的几十年里，科学家们发现并证实了一千多颗地外行星的存在，
which are planets that orbit other stars.
地外行星就是围绕其他恒星公转的行星。
And those star systems have quite a few differences from this one.
那些星系都跟我们这个星系有很多不一样的地方。
See, most solar systems have their larger planets orbit their host star closer than Mercury orbits the Sun.
看吧，多数太阳系中，比较大的行星会围绕主星公转，比水星离太阳还近。
In fact, in 1995, the exoplanet 51 Pegasi B was discovered,
其实，早在1995年，人类就发现了飞马座51B这颗地外行星，
which has half the mass of Jupiter but is 20 times closer to its star than the Earth is to the Sun.
它质量只有木星的一半，与其恒星的距离却比地球离太阳近20倍。
These types of exoplanets, which are creatively called “Hot Jupiters”,
这些地外行星都有一个极富创意的名字，“热木星”。
are quite common in other solar systems, but weirdly, they are missing from ours.
热木星在其他太阳系很常见，可是很奇怪，我们的太阳系却没有。
Coincidently, Hot Jupiter was also my college nickname. That's a story for another time.
巧了，热木星是我在大学时的绰号。这是后话了。
So why are our largest planets so far away from the Sun?
所以为什么我们最大的行星都离太阳那么远？
Well, to be honest, scientists aren’t quite sure.
呃，说实话，科学家也不太确定。
those good old scientists but, that hasn’t stopped them from coming up with hypotheses.
这些个科学家们~不过即使这样他们还是提出很多假说。
And this is where the Wandering Jupiter idea comes in.
其中就包括木星漫游学说。
Some scientists believe that when our solar system was a little youngin,
许多科学家相信我们的太阳系还年轻的时候，
the Sun was potentially surrounded by super-Earth rocky planets.
围绕太阳的有可能是一些叫作超级地球的岩态行星。
But then our good friend Jupiter moved inward, whose gravitational pull changed the orbits of these planets,
不过后来我们的好朋友木星向内侧旋转，它的地心引力改变了这些行星的运行轨道，
causing them to collide with one another and, ya know, smashed them into pieces,
使得他们相撞，粉身碎骨，
some of which were hurtled into the sun.
有些碎片飞进了太阳。
What a way to go!
多么艰难的路！
However, as Jupiter later retreated, being pulled away from the Sun by the formation of Saturn,
不过后来，土星形成产生的引力将木星拉回到自己的轨道，
any leftover debris eventually formed into the rocky planets we know today: Mercury, Venus, Earth, and Mars.
剩下的碎片最终形成我们今天知道的岩态行星：水星，金星，地球和火星。
And this does a good job of explaining why the inner planets are younger than the outer gas giants.
这很好地解释了为什么内侧的行星比外侧的气体巨星还年轻。
So, essentially, if this is actually what happened, if it weren’t for Jupiter, life on Earth would not exist.
所以，如果这些都是真的，如果没有木星，地球上的生命都根本不会存在。
Now, that’s not saying that life wouldn’t be possible at all,
并不是说地球上不可能出现生命，
but Earth may not have ever formed if Jupiter hadn’t come in and destroyed what was here before.
而是如果木星没有向内运行，没有血洗这些轨道的话，地球有可能都不会形成。
And not only is Jupiter potentially responsible for allowing Earth to form in the first place,
木星可能不仅推动了地球的形成，
but it also helps protect you now.
还在保护现在的你。
See, in the last decade alone, Jupiter has been hit by at least five comets or asteroids.
仅在过去的十年中，木星已经被至少五个彗星或者小行星撞击。
In fact, recent images from March 17th, 2016 show that Jupiter was hit by a small object*.
2016年3月17日的图片显示，木星被一小型物体撞击。
And these impacts are just the ones we’ve seen,
撞击的影响我们已经看到了，
some scientists predict that these collisions probably happen once to five times every month.
有些科学家预测这样的撞击可能每个月要发生一到五次。
And if it weren’t for Jupiter’s huge gravitational force deflecting these objects away from Earth,
如果不是木星这么大的吸引力把这些物体都吸走，被撞的可能就是地球，
you humans may have been struck by them instead.
被砸的就是你们这些人类了！
And honestly, as your friend, I don't recommend that at all.
说实话，作为朋友，我可不希望这样。
But, there’re also the theory that Jupiter might steer space rocks our way,
不过，也有理论认为木星可能会将太空中的陨石引到我们地球的轨道上，
possibly causing impact events.
可能会造成撞击事件。
Man, Jupitor, I just don't know any more.
木星啊，我什么都不知道。
but we should still all be grateful that Jupiter exists.
不过我们还是应该感激木星的存在。
I mean, if it didn’t, you probably wouldn’t be here watching this video, and that would be pretty sad, ya know?
我是说，如果没有木星，你可能就不能在这看视频了，多么悲伤，不是吗？
On the topic of hypothetical questions, what if Earth doubled in size?
说到假设性问题，如果地球变成现在的两倍大会怎么样呢？
Check out this video.
看这个视频。
How would that change things?
那会有什么影响？
well first of all, gravity would be very different.
首先，地心引力都不一样了。
the earth would have eight times as much mass and gravity would be twice as strong.
地球质量会变成现在的八倍，地心引力变成现在的两倍。
There’s a link in the description if you’re on mobile.
手机观看视频可以在描述区点击链接。
Make sure you come back every Monday for a brand new video.
每周一都要回来看新视频哦~
As always, I’m Blocko and this has been Life Noggin.
我是宝高，这里是脑洞大开的生命奇想。
Don’t forget to keep on thinking!
思考不要停！