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，然后我們起跳會發生什么呢？不幸的是，似乎沒啥。我的意思是我們都是地球上令人敬畏的人類啊。但是我們大家的質量與地球的相比，就像是什么都沒有。事實上，DOT PHYSICS計算出如果我們所有人聚集在一起，同時向上跳30厘米，我們會將地球推力我們一丁點兒。地球只會大約遠離我們百分之一氫原子的寬度。另外 因為我們全都起跳 然后回到原點，地球也會移動到原來的位置。
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.
所以我們這一跳不會在空間上改變地球的位置。但怎么會呢？70 億人一起跳啊，一定會導致某種地震活動，對不對？所以比方說，你同時有很多人，然后你讓他們都起跳一 、二、三。你能感受到嗎？BBC找了五萬人做這個實驗，然后發現1.5公里之外，之測量到里氏0.6級的地震。你要有現在地球人口，七百萬倍的人同時起跳來重現最近發生在日本的地震。所以，即使我們再厲害，比起地球的大小 我們也沒有多少。
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.
但是別感到太沮喪，我們大家的跳躍會包含許多能量，THE STRAIGHT DOPE 計算出即使只有全中國的人聚在一起，然后起跳，它的能量相當于500號TNT爆炸時釋放的能量。當然，500噸TNT對于地球來說算不上什么，地球重達6.588x10^21噸。為了讓你變得更強大，挑一張卡。我這有10張卡。比如說，讓你選這一張。砰，恭喜，我們剛剛從十張卡片里面抽走了一張。
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.
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.
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.
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，當你下次移動身體，Felicia 當你下次跳起來的時候，想想這件事：你對地球的作用和地球對你的作用相當。你的確有那種能力，那么大的功率。你也應該去瞧瞧GEEK & SUNDRY Felicia 的新頻道，這是我現在最近愛上的頻道之一。