Triangle Bobert snuck into my lab and hit the big red button on the half gravity machine I told him not to go next to.

Triangle Bobert 偷跑進我的實驗室，並按下我告訴它別靠近的「減半地球重力機器」的大紅色按鈕。

I probably should have made the button a little smaller.

我或許應該把按鈕做得小一點。

That's my fault.

那是我的錯。

I was able to reverse everything, but it did have me thinking, what if this happened to your world?

我能夠翻轉一切，但這的確讓我想到，如果發生在你的世界呢？

What if earth only had half its gravity?

如果地球只有現在一半的重力呢？

Well, first off, just what is gravity?

當然，首先，什麼是重力？

In general, we can define gravity as an attractive force that pulls two bodies together.

通常我們可以將重力定義為將兩個物體吸引在一起的作用力。

It's what keeps all of the planets in orbit around the sun and what keeps you from floating off into space.

這是讓所有行星保持在繞行太陽的軌道上的原因，也是讓你不會飄浮到太空中的力量。

And anything with mass has gravity.

所有有質量的物體都有重力。

The more massive something is, the greater gravitational pull.

物體質量越大，引力越大。

So a big, massive planet like the Earth is going to pull you toward it a lot more than one of my small pizza bagels will.

所以一個大質量的星球，像地球，將你拉向它的拉力比我其中一個比薩貝果還大。

Let me just get in here really quick.

讓我很快地吃一下。

Delicious.

好吃。

Distance also matters with gravity.

距離跟重力也有很大的關係。

The closer you are to something, the more gravity is going to draw you toward it,

你跟某物體距離越近，將你拉向它的重力越大。

and the farther away you are, the weaker the gravitational force will be.

而你離得越遠，重力便越弱。

Not only that, but gravity isn't even the same everywhere on Earth.

不只如此，地求上的重力也不是每個地方都相同。

According to NASA and data from the Gravity Recovery and Climate Experiment,

根據美國太空總署 (National Aeronautics and Space Administration，NASA) 以及重力恢復與氣候實驗室的數據，

gravity is ever so slightly stronger over places on Earth with higher concentrations of mass.

在地球上物質集中的地方重力會稍微強一些。

And these concentrations can even change over time.

而這些物質集中的地點會隨著時間改變。

But what would happen if the gravity here on Earth was suddenly cut in half?

但如果地球上的重力突然減半會發生什麼事？

It's pretty hard to tell exactly what would happen, especially since whatever would cause this sudden change would likely have other effects,

很難精確的告訴大家會發生什麼事，特別是不論什麼原因導致這個現象發生都會有其他的影響在，

but if we look at the universe around us, we can get a good idea of what might happen.

但如果我們看看周遭宇宙萬物，我們可以很好地理解會發生什麼事 。

To start off, you'd probably lose a bunch of weight.

首先，你可能會失去很多體重。

That's because our weight isn't actually a constant.

那是因為我們的體重事實上並非不變的。

It changes depending on where we are in the universe since it's determined by how much gravity is acting upon us.

它會根據我們在宇宙中的地點而改變，體重是由重力作用在我們身上的大小來決定。

For instance, if you weigh 100 Newtons on Earth, then you'd only weigh about 17 Newtons on the moon.

舉例來說，如果你在地球上有 100 牛頓重，你在月球上 只會有 17 牛頓重。

That's because up there, you'd only experience about a sixth of the gravity you normally do on Earth.

那是因為在月球上，你只會感受到地球上 6 分之 1 的重力。

So with half gravity, it makes sense that you'd only probably weigh about half as much.

所以在重力減半的狀況下，你只剩一半體重是有道理的。

That, if you survived, and everything on Earth seemed to carry on about the same but just with half gravity,

如果你存活下來，地球上的一切萬物似乎都會保持不變，

there would likely be health consequences.

但重力減半，可能對身體狀況造成影響。

That's because your body is always working against gravity.

那是因為你的身體一直在對抗重力。

Your muscles have to work against gravity even when you're relatively still,

即使當你靜止不動，你的肌肉仍然在作用以抵抗重力，

your bones have to support your weight, which is affected by gravity,

你的骨骼必須支撐重力影響下的體重，

and even your heart has to work against gravity to pump your blood throughout your body.

甚至你的心臟也必須對抗重力，將血液壓送至你的身體。

So at half gravity, and half your weight, your heart would likely become weaker,

所以在重力減半的狀況下，你的體重減半，你的心臟可能會變得虛弱，

your muscles might become smaller, and you could even lose bone mass.

你的肌肉可能變小，你的骨骼質量也會下降。

These are issues that astronauts face when experiencing weightlessness,

這些是太空人面臨失重時的問題，

so with half your weight, it stands to reason that similar things would happen but to a lesser extent.

所以當你的體重減半，按理說相似的事情就可能會發生，但嚴重性比較小一點。

But that's if everything carried on about the same, just with half gravity.

但那是在所有一切事情都不變只有重力減半的前提下。

If we actually suddenly lost half of the gravity on Earth, other things would probably change as a result.

如果地球真的突然失去一半的重力，其他事情也可能因此改變。

One of those things would be escape velocity.

其中一件事就是逃逸速度。

Since the Earth would have less gravity, how fast you would need to go to escape Earth,

既然地球重力變小，你逃離地球所需的速度，

otherwise known as escape velocity, would be less.

也就是所謂的逃逸速度，就會變小。

This means you wouldn't need to go as fast to get off this planet,

這意味著你不需要用很快的速度就能離開這個星球，

which might be a good idea if all this crazy gravity stuff actually happened.

這可能是個好事，如果重力改變這種事真的發生。

Two tickets to Mars please!

兩張到火星的票，謝謝！

I would like to chill with the aliens.

我想跟外星人去放鬆一下。

Let us know in the comment section below what we should talk next!

在評論區留言讓我們知道下一支影片該討論什麼！

Curious to know what it would take for the earth to explode?

好奇如果要讓地球爆炸需要什麼嗎？

Check out this video.

看看這支影片。

It only carved out a chunk of Earth a few kilometers deep.

它只在地球上劃出幾公里深的區塊。

Asteroids that are bigger, denser, or made of different materials could have the ability to hit us with enough power to shatter our planet.

更大、密度更高或由不同物質組成的小行星有足夠的能力在撞擊後，粉碎我們的星球。

As always, my name is Blocko, this has been Life Noggin, don't forget to keep on thinking!

一如往常，我的名字是 Blocko，這是 Life Noggin，別忘了保持思考。