为什么我们感觉不到地球在自转？

复合地板。

Laminata.

大脑探索宇宙。

Brains on Universe.

你正在收听《大脑探索》，我们认真对待每一个好奇心。

You're listening to Brains On, where we're serious about being curious.

有一个古老的故事，大概是这样的。

There's an old story that goes something like this.

两条鱼在水里游着。

Two fish are swimming in the water.

一只乌龟站在一旁，跟鱼打招呼说：早上好啊，鱼儿。

And a turtle stands by and says, good morning, fish.

水感觉怎么样？

How's the water?

两条小鱼笑了笑，点点头，继续游走了。

The two younger fish smile and nod and swim on for a bit.

这时，其中一条鱼突然停了下来，问另一条：水到底是什么东西？

Then one fish stops and says to the other, what the heck is water?

鱼根本没注意到水，因为它们一辈子都在水里。

The fish didn't notice the water because they've been in it all their life.

它们从来没想过这回事。

They never thought about it.

重点是，我们周围有很多东西，因为一直存在，所以我们根本注意不到。

The point is that there are things all around us that we just don't notice because they've always been there.

就像你自己的唾液的味道。

Like the taste of your own spit.

或者普通空气的气味。

Or the smell of plain old air.

又比如，此刻地球正以每小时几百英里的速度自转，可我们却一点都感觉不到。

Or how right now the earth is spinning hundreds of miles an hour and somehow we don't feel it.

对。

Yeah.

这速度可真快，但我从来没感觉到过。

That's a lot of speed, but I've never noticed it.

我也没注意过。

Me neither.

所以抓紧了，我们来解释一下为什么会这样。

So hold on tight, and we'll explain why that is.

你喜欢神秘的声音吗？

Do you love mystery sounds?

我超爱神秘的声音。

Because I love mystery sounds.

所以我才在这儿的神秘声音库房里，欣赏这些奇妙的声音，比如这个。

That's why I'm here in our mystery sound storage room, just admiring all the wonderful sounds, like this one.

这是神秘声音，还是动听的音乐？

Is that a mystery sound or sweet music?

我根本分不清。

I can't tell the difference.

你猜到是狗项圈的声音了吗？

Did you guess that it was my dog's collar?

猜对了，真不错。

If so, great job.

哦。

Oh.

哦。

Oh.

那这个呢？

How about this one?

我特别喜欢这个。

I love this one.

你听出来是什么了吗？

You know it?

是我抖餐巾的声音。

It's me fluffing a napkin.

谁会忘了这个呢？

And who could forget this?

给沙鼠梳毛？

Combing a gerbil?

我知道。

I know.

太简单了。

Too easy.

这是我自己用塑料叉子改造成梳子，给我那名叫拉里的沙鼠梳毛时发出的声音。

It's the sound of a plastic fork I fashioned into a comb to comb the hair of my gerbil named Larry.

我们都听过成千上万遍了。

We've all heard it a thousand times.

我特别喜欢这种神秘声音，因为它们会让你停下来仔细听。

I love mystery sounds because they make you stop and pay attention.

它们能让你集中注意力。

They make you focus.

它们会让你用不一样的眼光去看待和聆听这个世界，这正是我们做《Brains On》的初衷。

They make you see and hear the world a little differently, and that's what we try to do at Brains On.

如果你觉得换个角度看世界很重要，那不妨加入 Smarty Pass。

If seeing the world a little differently matters to you, then you should join Smarty Pass.

我们会定期和听众在线互动，用全新的神秘声音来挑战大家。

We do regular online hangs with listeners where we challenge them with fresh mystery sounds.

我们还有读书会，Smarty 的成员可以和我们一起讨论书籍，还能免费收听无广告版的《Brains On》和《Forever Go》等节目。

We have a book club where Smarty pals can discuss a book with us, plus you can get ad free versions of Brains On, Forever Go, and more.

注册非常简单。

It's super easy to sign up.

直接访问 brainson.org/smartypass 就行了。

Just go to brainson.org/smartypass.

更重要的是，你的支持能帮助我们继续为这样的声音提供一个温暖的家。

And most importantly, you can help support Brains On so we can provide a happy home for sounds like this.

我真能整天听着塑料叉子给拉里这只豚鼠梳毛的声音。

I could listen to Larry the gerbil getting combed with a plastic fork all day.

所以快来加入 Smarty Pass 吧。

So join Smarty Pass.

拉里和我都谢谢你。

Larry and I both say thanks.

Brains On，我们继续。

Brain's on.

你正在收听 Brains On，属于 Brains On 宇宙的一部分。

You're listening to Brain's on, part of the Brain's on universe.

我是莫莉·布卢姆，今天我的搭档是来自西雅图的里安。

I'm Molly Bloom, and my cohost today is Reean from Seattle.

嗨，里安。

Hi, Reean.

嘿，莫莉。

Hey, Molly.

你把演播室布置得真棒，那些镜子和迪斯科球。

I love what you've done with the studio, the mirrors, the disco ball.

那是把芭蕾把杆吗？

Is that a ballet bar?

那不是我。

It's not me.

那是Gongador。

It's Gongador.

那个痴迷舞蹈的怪物住在我们总部，他把这儿布置成舞蹈室，好在这里拍他的新视频播客。

The dance obsessed monster who lives at our headquarters, he decorated it to look like a dance studio so he can tape his new video podcast here.

叫《怪物舞步》。

It's called monster moves.

《怪物舞步》？

Monster moves?

就是那种节目，一群大怪物围坐在一起，聊电影和音乐剧里那些著名的舞蹈编排。

It's one of those podcasts where a bunch of giant monsters sit around and talk about famous choreography from movies and musicals.

哦，那种啊。

Oh, one of those.

希望他的节目能在一堆巨兽讨论电影和音乐剧经典舞步的播客里脱颖而出。

I hope his podcast can stand out from all the other podcasts where giant monsters discuss famous choreography for movies and musicals.

我知道哥斯拉的那个节目《巨步》特别火。

I know Godzilla's podcast, Giant Steps, is a mega hit.

是啊。

Yeah.

他就是受这个启发的。

That's what inspired him.

还有金刚的《金刚与舞》。

That and King Kong's podcast, Kong and Dance.

当然了。

Of course.

经典节目了。

A classic podcast.

不过今天咱们聊点别的，谈谈地球，回答一下你提的问题，里安。

Anyway, today we're talking about the earth and answering a question that you asked us, Reean.

是的。

Yeah.

我一直想知道，为什么我们感觉不到地球在自转呢？

I wanted to know why can't you feel the earth spinning?

好问题。

Great question.

现在，你、我，还有地球上的一切都在不停地旋转，可我们就是一点都感觉不到。

Right now, you, me, and everything on the planet is spinning, spinning, spinning, and yet somehow we never feel it.

就像头发一直在长，可我们也从来感觉不到它在长一样。

Kind of like how our hair is always growing, but we never feel that either.

哦，我能感觉到。

Oh, I feel it.

每一秒都能感觉到。

Every second.

每一刻我都感觉我的卷发一点点往上长，越长越高，像伊卡洛斯飞得太靠近太阳，直到有一天——咔嚓。

Every single moment, I feel my curls creeping higher and higher, reaching for the sky, like Icarus flying too close to the sun until one day, snip.

头发剪了，我就换个新发型。

They get clipped and I get a cute new haircut.

明白了。

Okay.

所以，Reean，是什么让你对地球自转感兴趣了？

So, Reean, what got you curious about the earth spinning?

我是在车里看着车轮转的时候突然想到的，地球不也在转吗？

I got this question when I was on the car looking at the wheel and suddenly, I thought the earth is spinning too.

那为什么我们感觉不到呢？

So why can't we feel it?

问得好。

Great question.

你喜欢那种转得特别快的游乐设施吗？

Do you like rides that spin a lot?

就像游乐园里的旋转木马那种？

Kinda like, you know, the merry-go-round on a playground?

我不太喜欢转圈，但看东西像陀螺一样转还挺有意思的。

I don't really like spinning, but it's cool to see things spinning like a top.

你容易晕吗？

Do you get dizzy easily?

是的。

Yes.

特别容易。

Very easily.

那你在车里会不会觉得恶心？

So does that mean you get, like, motion sick in cars too?

没那么严重。

Not that much.

只有当我转圈的时候才会晕。

I just get dizzy when I'm spinning.

对。

Mhmm.

所以

So

你头晕的时候，喜欢那种感觉吗？

when you are dizzy, do you like how that feels?

不喜欢。

No.

感觉怪怪的。

It's weird.

对。

Mhmm.

我真的不太喜欢。

I don't really like it.

我懂。

I get it.

我小时候其实还挺喜欢头晕的感觉，所以会故意转圈。

When I was little, I actually kinda like to feel dizzy, so I would like spin on purpose.

但现在我长大了，真的特别不喜欢这种感觉。

But now that I'm older, I really don't like that feeling at all.

所以，Reean，当你遇到一个大问题时，是想马上找到答案，还是更愿意慢慢想一想？

So, Reean, when you have a big question, do you like to find the answer right away, or do you like to just kinda, like, ponder it?

我更喜欢慢慢想一想。

I like to ponder it more.

你在哪里思考得最好？

Where do you do your best thinking?

我就坐在沙发上，盯着电视，但电视其实没开。

I'm just, like, sitting on the couch and, like, looking at the TV, but the TV is not really on.

对。

Mhmm.

然后我就一直想，直到冒出一个想法或者什么的。

So then I just keep thinking until I think of an idea or something.

我喜欢这样。

I like that.

所以，电视其实就像个替身，让你能盯着自己的思绪发呆。

So, like, the TV is sort of like a stand in for you to, like, watch your own thoughts.

是的。

Yeah.

这真有意思。

That's really cool.

我很喜欢我们一直在不停地探讨。

Well, I love that we are spinning all the time.

想想这些事特别有趣。

It is very fun to think about.

对。

Yeah.

而且你能看出来我们在转圈，因为太阳每天都会升起又落下。

And you can tell we're spinning because the sun rises and sets every day.

没错。

That's right.

太阳其实并不是每天绕着地球转一圈。

The sun isn't actually going around our planet once every twenty four hours.

真正转的是地球，它让我们不断进入和离开阳光。

Instead, it's our planet that is spinning us into and out of the light of the sun.

这是因为地球在沿着一根轴自转。

That's because our planet is spinning on an axis.

就像陀螺转，或者手指上转着的球。

Like a spinning top or a ball spinning on someone's finger.

我们把这个叫做自转。

We call this a rotation.

地球上的每一天，就是一次完整的自转。

Each day on Earth is one rotation.

也就是说，地球每24小时绕着自己的轴转一圈。

That means our planet rotates or spins once around every twenty four hours.

想象一下你现在所在的位置。

So imagine the spot you're in right now.

当你们所在的位置刚刚开始转向太阳时，那就是日出了。

When that spot rotates to where it is just starting to face the sun, that's sunrise.

地球一直在转，对我们来说，看起来就像是太阳在天空中移动。

The Earth keeps spinning, and to us on Earth, it looks like the sun is moving across the sky.

后来，随着地球继续转动，那一面就渐渐背离阳光，进入阴影中。

And later, as it keeps spinning, that side turns away from the light and goes into shadow.

对那一面来说，那就是夜晚了。

That's nighttime for that side.

地球转一圈，就是完整的一天。

One full rotation is one full day.

真有意思。

Cool facts.

不过我有个问题想问问你。

But riddle me this.

地球为什么会转呢？

Why does the planet spin anyway?

又是个好问题。

Another great question.

在地球出现之前，甚至在太阳形成之前，我们的太阳系只是一片太空中漂浮的气体云。

Before Earth existed, even before the sun existed, our solar system was just a cloud of gas in space.

太空中的气体。

Space gas.

那片气体云里充满了分子，它们彼此碰撞，很多分子以不同角度相撞，于是就开始旋转起来。

That cloud of gas was full of molecules that bumped into each other, and lots of those molecules hit each other various angles, which caused them to spin.

就像你踢足球时要是踢到球的侧面，球就会转起来一样。

Kind of like how if you kick a soccer ball at an ankle, you can get a good spin on it.

没错。

Exactly.

越来越多的分子开始旋转、碰撞，转速越来越快，最终整片气体云就像水流进下水道一样飞速旋转。

More and more of them started spinning and knocking into each other, creating more spin until the whole gas cloud was swirling like water going down a drain.

后来，这片旋转的气体云中的一部分形成了太阳，另一些部分则慢慢凝聚成了地球。

Eventually, some of that spinning cloud of gas formed our sun, and other parts of that cloud of gas eventually formed Earth.

因为组成地球和太阳的那些碎片原本就在旋转，所以地球和太阳至今还在转。

And because the pieces that came together to form the Earth and sun were spinning, the Earth and sun kept spinning.

这种旋转从未停歇。

The spin never stopped.

所以，正是因为那些随机的气体分子相互碰撞产生旋转，我们的星球才得以自转，有了昼夜交替？

So thanks to random bits of gas bumping into each other and creating a spin, our planet now rotates and we have day and night?

仔细想想，这真让人震撼。

Kind of blows your mind when you really think about it.

还有更惊人的一点：地球自转的速度非常快。

And another amazing thing is that the Earth is spinning really fast.

想想猎豹、赛车或者高铁。

Think of a cheetah, a race car, or a bullet train.

跟地球的自转比起来，那些都慢得像蜗牛。

Those are slowpokes compared to the Earth's spin.

猎豹最快能跑每小时七十英里左右。

A cheetah can run around 70 miles per hour.

赛车和高铁都能跑出每小时两百英里的速度。

A race car and a bullet train can both zip along at 200 miles per hour.

但地球每小时自转的速度大约是一千英里，尤其是在赤道上，那就像地球仪中间那条环绕的腰带。

But our planet rotates every moment at a speed of about 1,000 miles an hour if you measure at the Equator, which is like the belt around the middle of a globe.

如果你在公园里看到一个旋转木马，

Now if you were at the park and you saw a merry-go-round

天哪。

Woah.

旋转木马。

A merry-go-round.

我最喜欢这个了。

That's my favorite.

要是你跳上那个旋转木马，

And you hopped on that merry-go-round.

咱们转起来吧。

Let's spin.

再快点。

Make it go faster.

更快点。

Faster.

如果它转得像地球一样快，达到每小时一千英里，你不仅会感觉到，还会被甩出去，飞得老远。

And it went so fast it reached a thousand miles an hour like the Earth, you would not only feel it, you'd be flung off and go flying.

哇哦。

Wee.

一点都不后悔。

No regrets.

那为什么我们没有被甩出地球呢？地球可算是有史以来最大的旋转木马了。

So why aren't we flung off the Earth, which is basically the largest merry-go-round ever?

我们甚至都不会头晕。

We don't even get dizzy.

我们马上就会解释这个问题。

We'll answer that in just a minute.

不过现在，先让我们竖起耳朵，来听一个声音。

But for now, let's give our ears a spin and check out the

神秘声音。

Mystery Sound.

听好了。

Here it is.

那是鲨鱼的声音。

That was shark.

能再放一遍吗？

Can we hear it again?

好。

Okay.

雷恩，你觉得这是什么声音？

Reean, what do you think?

就是当你在船上，打开窗户，能听到周围各种声音，然后再把窗户关上那种感觉。

Maybe when, like, you're on a boat and then, like, you open a window and, like, you can hear, like, all the sounds and you close it again.

我觉得这声音像是从外面传来的。

It sounds like it's outside to me.

对。

Yeah.

背景里好像有种奇怪的轰隆声。

There's like weird, like, rumble sound at the background.

嗯哼。

Mhmm.

我好像听到鸟叫声了？

I think I heard birds maybe?

好。

Okay.

我觉得这声音确实来自外面。

I think it's outside.

我猜这可能是游乐场的设备发出的声音。

I'm gonna think like a piece of playground equipment.

但那声音到底是怎么来的？

But what makes that sound?

我也不清楚。

I don't know.

比如说，有人的裤子卡在秋千上了。

Let's say, someone got their pants stuck in a swing.

我也不明白裤子怎么会卡在秋千上。

I don't know how somebody's pants will get stuck in a swing.

他们想把裤子拽出来，结果裤脚被勾住了。

They're trying to get their pants they're like the hem of their their cuff

哦，对啊。

Oh, yeah.

卡住了。

Stuck.

这想法还挺合理的。

That might be a pretty good idea.

真的吗？

Like Really?

我觉得是秋千架发出的声音，背景里则是孩子们在玩耍。

Because I think like the swing set makes that sound and then the background is, like, the kids, like, playing.

明白了。

Okay.

我觉得这跟秋千架有关。

I'm gonna say swing set related.

你那个船的点子不错，不过我们留到节目结尾再听一次、猜一猜，然后揭晓答案。

I like your boat idea, but we'll get another chance to hear it and guess and hear the answer at the end of the show.

我们正在制作一期关于灯泡的节目。

We're working on an episode all about light bulbs.

在漫画或卡通里，灯泡常被用来表现某人灵光一现。

Light bulbs are often used in comics or cartoons to show when someone gets a bright idea.

他们可能还会喊一句‘我想到了’或者‘我明白了’。

They may also shout something like, I've got it, or Eureka.

就是说，

Like,

可能是第一个想到把辣鸡翅配冰凉顺滑的牧场酱的人。

maybe the first person to think of dipping spicy chicken wings in cool, soothing ranch dressing.

他们大概会大喊：‘完美搭配！’

They probably shouted, Eureka, a perfect pair.

没错。

Exactly.

所以我们想听听你的想法。

So we wanna hear from you.

当你灵光一现的时候，你觉得我们应该喊什么词？

What word do you think we should shout when we have a light bulb moment?

Reean，你灵光一现的时候会喊什么？

Reean, what would you shout when you have a bright idea?

我会喊：‘呜嘎布嘎。'

I would shout, ooga booga.

我真的很喜欢这个。

I really like that.

下次我有好点子的时候，能用这个喊一声吗？

Is it okay if I borrow that next time I get a good idea?

当然可以。

Sure.

太感谢了。

Thank you so much.

各位听众，赶紧录下你的点子，发到 BrainsOn.org/contact 告诉我们吧。

Well, listeners record your idea and send it to us at BrainsOn dot org slash contact.

我们超期待听到你的创意。

We can't wait to hear what you come up with.

问题和神秘声音也欢迎一起发来。

And you can send questions and mystery sounds there too.

谢谢收听，别忘了继续关注。

Thanks, and keep listening.

本期节目由Shopify赞助。

Today's episode is sponsored by Shopify.

当我们BrainZone独立运营时，很多事情都要从头摸索，压力真的挺大的。

When we went independent here at BrainZone, there was a lot to figure out, and it was pretty overwhelming.

刚开始做一件事的时候，总觉得待办清单永远都做不完。

And when you're starting something new, it just feels like the to do list keeps growing and growing and growing.

但这时候，找到一个不仅能帮上忙、还能把事情简化的好工具，真的能改变一切。

But that's why finding the right tool that not only helps you out but simplifies everything can be a game changer.

对我们来说，Shopify就是这样的工具。

For us, one of those tools is Shopify.

Shopify是全球数百万商家背后使用的电商平台，占美国电子商务总量的百分之十。

Shopify is the commerce platform behind millions of businesses around the world and 10% of all e commerce in The US.

Shopify是你的电商专家，从库存管理、国际物流到退货处理，样样精通。

Shopify is your commerce expert with world class expertise in everything from managing inventory to international shipping to processing returns and beyond.

如果遇到问题，Shopify还有获奖的24小时客服团队随时为你提供帮助。

And if you get stuck, Shopify is always around to share advice with their award winning twenty four seven customer support.

今天就用业内最靠谱的合作伙伴Shopify开启你的事业吧，马上开始体验。

Start your business today with the industry's best business partner, Shopify, and start hearing.

前往 shopify.com/brainson，注册只需每月1美元的试用。

Sign up for your $1 per month trial at shopify.com/brainson.

直接访问 shopify.com/brainson。

Go to shopify.com/brainson.

就是 shopify.com/brainson。

That's shopify.com/brainson.

欢迎收听《怪物动起来》，一档由怪物们聊舞蹈的播客。

Welcome to Monster Moves, a podcast where monsters talk dance.

我是主持人贡加多。

I am host Gungador.

今天的嘉宾是大脚怪和克拉肯。

Guest today are Bigfoot and Kraken.

你好，贡加多。

Hello, Gungador.

能来这里真的非常开心。

Truly a pleasure to be here.

饿得不行了。

Crockin' hungry.

今天我们要聊的是一部经典舞蹈电影《雨中曲》，主角是Gungador的偶像吉恩·凯利。

Today, we talk about famous dance movie, Singing in Rain, starring Gungador's hero, Gene Kelly.

没错。

Yes.

这部电影真的很棒。

It's quite the film.

尤其是吉恩·凯利在雨中跳舞的那一段，动作堪称经典，完全是好莱坞的魔法。

And Gene Kelly's iconic choreography in this scene where he is literally dancing in the rain is pure Hollywood magic.

他既充满活力，又洋溢着纯粹的快乐。

He's both so athletic and so joyous.

更惊人的是，拍那段戏的时候，他正发着高烧，体温高达39.4度。

And to think while filming that scene, he was ill and running a fever of 103 degrees.

但你看不出来，因为凯利一直都很专业。

But it doesn't show because Kelly is ever the professional.

说得很对。

Great points.

你对这部电影有什么看法？

What are cracking thoughts on movie?

下雨。

Rain.

湿透了。

Wet.

另一个不错的观点。

Another good point.

接下来，冈加罗要分享他心目中《弗兰肯斯坦》音乐剧的理想选角。

Coming up, Gungaro's dream fan cast for Frankenstein the musical.

这里是《大脑出击》。

This is Brains On.

我是莫莉，今天和我的伙伴里安一起。

I'm Molly, here with my buddy, Reean.

我们在聊地球的自转。

And we're talking about the spin of the earth.

就是这个站点的旋转。

The rotation of this station.

地球的转动。

The twirl of the world.

我们很好奇，既然地球转得这么快，为什么我们却感觉不到呢？

And we're wondering if the planet is going round and round so fast, why don't we feel it?

这有几个主要原因。

There are a few main reasons.

其中一个跟转动的平稳性有关。

One has to do with how smooth the spin is.

没错。

Right.

地球已经以非常稳定的速度旋转了很长时间。

The earth has been rotating at a very constant speed for a very long time.

这个速度其实几乎没有变化。

That speed doesn't really change.

我们最能感觉到运动，是在加速或减速的时候，比如汽车突然刹车。

We notice motion the most when things are speeding up or slowing down, like when a car suddenly breaks.

或者飞机加速起飞的时候。

Or a plane speeds up to take off.

或者改变方向的时候，比如你骑自行车，突然拐弯避开一个坑。

Or when we change directions, like when you're riding your bike but suddenly swerve to miss a pothole.

速度和方向的这些变化才会让人感觉到在动。

Those changes in speed and direction feel like movement.

但想象一下，你正在坐一趟长途火车。

But imagine you're on a long train ride.

再想象一下，火车的所有窗帘都拉上了。

And imagine you're on that train with all the window shades closed.

如果火车匀速行驶，轨道又平又直，你根本感觉不到自己在动。

If the train is going at a very steady speed and there are no bumps or turns in the track, you won't notice that you're moving at all.

就像你只是待在一个普通的静止房间里一样。

It'll just feel like you're in a normal still room.

只有当你拉开窗帘，才会看到外面的世界飞速掠过。

It's not until you open the shades that you see the world whizzing by.

但在火车这个空间里，所有的座椅、你带的书，甚至空气，都和你以同样的速度移动。

In the room of the train, though, all the seats, the books you've brought, even the air, it's all moving the same speed as you.

所以对你来说，它们看起来根本没动。

Which means to you, it seems like it's not moving.

从你的角度看，它们完全是静止的。

That is relative to you, it's perfectly still.

这叫做相对运动。

This is called relative motion.

现在，如果我们把这个道理应用到整个地球，丽瑞斯正平稳地穿越太空。

Now when we apply this to the whole planet, Liris is moving very smoothly through space.

一路上没有任何颠簸，也没有突然加速或减速。

There are no bumps along the way and no dramatic speeding up or slowing down.

而且所有的植物、山脉、建筑、海洋和动物，都跟你以完全相同的速度移动。

Plus, all the plants, mountains, buildings, oceans, animals are all moving at exactly the same speed as you.

所以对你来说，它们看起来根本没在动。

Which means again to you, it seems like they aren't moving at all.

它们都静止不动。

They're staying still.

这就是我们感觉不到地球自转的一个原因。

So that's one reason we don't feel the spin of the earth.

但那为什么不会被甩出地球呢？

But what about being flung off the planet?

是的。

Yeah.

即使速度是恒定的，那速度也快得惊人。

Even if the speed is constant, it's a lot of speed.

当物体在地球上旋转时，往往会向外飞出去。

And when things spin on earth, they tend to fly outward.

想象一下，把一堆网球放在之前说的旋转木马上。

Think of putting a bunch of tennis balls on that merry-go-round from before.

让它飞速旋转，网球就会被甩飞出去。

Give it a super spin, and the balls will go flying off.

这种把网球从旋转木马上甩开的运动，有时被称为离心力。

That motion flinging the balls away from the merry-go-round is sometimes called centrifugal force.

而一个旋转的星球会产生相当强大的离心力。

And a spinning planet makes some pretty strong centrifugal force.

但事实上，有一种更强的力在阻止你我以及所有东西被甩到太空中。

But it turns out there's an even stronger force stopping it from flinging you and me and everything else out into space.

这种力就是

And that force is

重力。

Gravity.

重力。

Gravity.

所以没错，确实有一种离心力在作用于我们，想把我们甩到太空里，但我们不会飞出去，因为重力在起相反的作用。

So, yes, there is, in fact, a centrifugal force acting on us, trying to fling us into space, but we don't fly off because gravity is doing the opposite.

重力正试图把我们牢牢地压在这颗巨大的行星上。

Gravity is trying to pin us down on this massive planet.

重力比离心力强得多。

And gravity is much, much stronger than the centrifugal force.

跟重力相比，离心力太弱了，我们根本察觉不到。

Compared to the gravity, it's so weak that we don't even really notice it.

我们只感觉得到重力。

We just notice the gravity.

重力。

Gravity.

尽管我们一直在不停地旋转，但根本感觉不到。

So even though we are constantly twirling, it doesn't feel like we are.

这在一定程度上要归功于相对运动，还有旋转的平稳性。

That's in part thanks to relative motion and how smooth the spin is.

另一方面，也是因为重力把我们的脚牢牢吸在地面上，这很好，因为要是能感觉到地球在转，我们早就晕得不行了。

And in part thanks to gravity keeping our feet on the ground, which is great because if we could feel the earth spinning, we'd be dizzy all the time.

这就引出了一个问题。

That brings us to this question.

你好。

Hi.

我叫亨利，来自纽约市的一家商店。

My name is Henry, and I'm from a store in New York City.

我的问题是，为什么我们转圈的时候会头晕？

My question is, why do we get dizzy when we spin around?

我们先来处理一下听众来信，然后再回答这个问题。

We'll answer that right after we check the mailbag.

嗨。

Hey.

我是桑丁，嘿，大家好。

It's Sandin, and hey ho.

咱们来看看邮件吧。

Let's go check the mail.

哦。

Oh.

这封信给我的感觉，怎么说呢，挺有音乐感的。

This one feels, I wanna say musical.

咱们看看里面写了什么。

Let's see what's inside.

你好，脑力地带。

Hi, Brain Zone.

我叫沃尔特，来自伊利诺伊州。

I'm Walter, and I'm from Illinois.

我自个儿编了首脑力地带的主题曲，还加了些和弦什么的。

So I improvised the Brain Zone theme song, and I added like some chords and stuff.

希望你喜欢。

Hope you like it.

慢慢享受。

Enjoy.

特别喜欢你的节目。

Love your show.

再见。

Bye.

好的。

Okay.

刚才那首太棒了。

That that was rad.

非常感谢你寄来这个。

Thank you so much for sending that in.

击个掌，等等。

High five or wait.