2015-2-28 14:30










And what if every single person on earth jumped at the exact same time? Could it cause an earthquake? Or would we not even be able to tell? Well, first things first, let's talk about the earth's rotation. The earth's spins since why we have night and day, and it spins quickly. At the equator, the earth is spinning at more than 1000 miles per hour.

Now a spinning ice-skater can speed up by moving mass closer to the center. And the earth is no different. In fact, if you get down on the ground right now, and move your mass closer to earth's center, technically, you will speed up earth's rotation making this day shorter. Now, the change that you would make to the earth's rotation is way smaller than we can even measure. But it's calculable and the impact can be quite impressive when you talk about redistributing more mass than just one person.


For instance, last year, the earthquake in Japan redistributed so much of earth's mass towards the earth's center that everyday, since than, has been 1.8 micro-second's shorter. But that was a giant geological event. What can we humans do to the earth all on our own? I mean, there are more than 7 billion of us now. What if we all got together in one place and jumped? What would that even look like?

Interestingly, if you took the entire human population of earth, and had them all live in one place with the same density that people live in New York City, you could fit everyone all of us into the state of Texas. But that's living, not standing around in the crowd which is how we would probably wanna do to jump. If every single person alive right now on earth stood shoulder to shoulder, you could fit all of us into the city of Los Angeles. It would be an incredible sight to be hold: A mere 500 square miles containing every single on earth.

OK, so then we jump, what happens? Unfortunately, not much. I mean, we are all awesome people here on earth. But our collective mass compared to the mass of the entire earth, it's like nothing. In fact, DOT PHYSICS calculating that if all of us were to get together in one location and all jump 30cm into the air at the exact same time, we would push the earth away from us a tiny amount. Earth would only move away from us about 1/100 of the width of a single Hydrogen atom. And here's another thing, because we are all jumping and then going back to where we started, earth is just going to move back to where it started.
好,然后我们起跳会发生什么呢?不幸的是,似乎没啥。我的意思是我们都是地球上令人敬畏的人类啊。但是我们大家的质量与地球的相比,就像是什么都没有。事实上,DOT PHYSICS计算出如果我们所有人聚集在一起,同时向上跳30厘米,我们会将地球推力我们一丁点儿。地球只会大约远离我们百分之一氢原子的宽度。另外 因为我们全都起跳 然后回到原点,地球也会移动到原来的位置。

So, our big jump won't be able to change earth's position in space. But come on,7 billion people all jumping together that's gotta be able to cause some sort of seismic activity ,right? So let's say you have a lot of people altogether at one place, and you have them all jump on one, two, three. Did you feel that? Well,the BBC did this with 50,000 people and discovered that a kilometer and a half away, it only registered as a point six on the Richter scale, You would meet 7 million times more people than even live on earth right now to jump at once to recreate the earthquake that recently happened in Japan. So, even though we were all awesome, compared to the size of the earth, we are not much.
所以我们这一跳不会在空间上改变地球的位置。但怎么会呢?70 亿人一起跳啊,一定会导致某种地震活动,对不对?所以比方说,你同时有很多人,然后你让他们都起跳一 、二、三。你能感受到吗?BBC找了五万人做这个实验,然后发现1.5公里之外,之测量到里氏0.6级的地震。你要有现在地球人口,七百万倍的人同时起跳来重现最近发生在日本的地震。所以,即使我们再厉害,比起地球的大小 我们也没有多少。

But don't get too discouraged, our collective jump will contain a lot of energy; THE STARIGHT DOPE calculated that even if only the people who lived in China got together and jumped, their jump would be equivalent of 500 tons of TNT. Of course,500 tons of TNT doesn't do much to an earth, that weights 6 Sextillion 588 Quintillion tons. To make yourself feel more powerful, pick a card. I've got 10 of them here, let's say, you choose this one. Boom, congratulations, we have just decimated this deck of cards.
但是别感到太沮丧,我们大家的跳跃会包含许多能量,THE STRAIGHT DOPE 计算出即使只有全中国的人聚在一起,然后起跳,它的能量相当于500号TNT爆炸时释放的能量。当然,500吨TNT对于地球来说算不上什么,地球重达6.588x10^21吨。为了让你变得更强大,挑一张卡。我这有10张卡。比如说,让你选这一张。砰,恭喜,我们刚刚从十张卡片里面抽走了一张。

Why, well, because technically decimate does not mean obliterate completely.Deci,10,it means to take away one tenth of something.So the next time you take a quiz,and don't do so well on it,you only get 10%.Well,sure that's an F.But,by getting 10% of them right,you decimated that quiz.And since we've been talking about crowds,let's talk about Youtube crowds.Youtube audiences that if you count that you see the bottom of every video,And get some perspective on it,we'll began with Dunbar's Number.It's an estimation of the maximum number of people we can have stable social relationships with at an given moment.
为什么?因为严格意义上来说“decimate“不是完全抹杀的意思。“deci“10 它的意思是某物的十分之一。那么当你下次做小测验并且考砸了,你只拿到10分。当然,毫无疑问是个F.但是,因为你做对了10%所以你在10题中就对了1道。既然我们一直在讨论人群,来说说Yotube上的看客吧。Yotube看客们,如果你们能看到每个视频底下的信息,稍加观察的话,那么我们先从邓巴数开始说起吧。这是我们在某个时间内能够维系稳定社会关系的最大人数。

And it's based on the size of our Neocortex.These aren't just acquaintances,these are people you have social contact with.A network where you know how everyone relates to everyone else.And the number is usually given to be somewhere between 100 and 230.Which means that when a Youtube video receives more than 230 views from different people more people have seen that video that you could ever realistically hope to know well at a given moment.If a video has more than 100,000 views from different people,more people have seen that video than you will ever meet in your life.
它与我们大脑的新皮质有关。这些并非仅仅相识的人,而是你能与之进行社会交往的人。一个你对人与人之间关系了如指掌的网络。这个数字大约在100到230人之间。这也就意味着 当一个Youtube视频观看人数超过了230,观看视频的人数就比你希望能在一段时间内熟识的人数多了。如果一个视频被超过10万不同的人观看,那么观看视频的人数就比你一生中能够遇到的人多了。

And by meet,I mean shake hands with,learn their name,talk to them for a bit.I mean think of it this way,you and me,we are only statistically expected to live around 28,470 days.So even if you are to meet someone,two three people everyday of your life including when you are a baby.you still wouldn't meet as many people as have seen that Youtube video with 100,000 views.

Keep this in mind, even though you or even a large group of us can do much to change the earth's location or rotation.we can affect it a little bit.Newton's Third Law guarantees this,if you weigh 150 pounds,the earth is pulling you down with a force of 150 pounds.But you are also pulling up on the earth with a force of 150 pounds.If you fall 3 meters,the earth is pulled you down 3 meters,but you have also exerted an equal and opposite force on the earth.Of course it's a lot bigger.SO if you fall 3 meters,you pull the earth up about a billionth of the width of a proton.which ain't bad.
请记住,即使是你或者是我们一大群人能够为改变地球的自转或位置做出许多事,我们能在极轻微程度上产生影响。牛顿第三定律向我们保证 如果你的体重是150磅,那么地球就是对你施加一个向下的,大小为150牛的力。但是你也对地球施加一个向上的,大小为150牛的力。如果你下降3米,就是说地球把你向下拉3米,但你也对地球施加了一个大小相等,方向相反的力。当然这个看上去大多了。如果你下落3米,地球就被你拉上来了质子直径十亿分之一垢距离。似乎还不错。

So the next time you move your body,the next time you jump,Felicia,think about this:you just affected the earth as much as it affected you.You got that kind of power,speed of power.You all should go check out GEEK & SUNDRY,Felicia's new channel,it's one of my new favorite names.
那么,当你下次移动身体,Felicia 当你下次跳起来的时候,想想这件事:你对地球的作用和地球对你的作用相当。你的确有那种能力,那么大的功率。你也应该去瞧瞧GEEK & SUNDRY Felicia 的新频道,这是我现在最近爱上的频道之一。