Regardless of whether or not they succeed, their ambitious idea really made us wonder.

不管他們會不會成功，他們野心勃勃的主意讓我們開始思考。

What would happen if Earth had two moons?

如果地球有兩顆月亮，會發生什麼事？

Well, it wouldn't be pretty.

情況不會很樂觀。

Imagine the moon's identical twin comes hurtling by and is trapped by Earth's gravity.

想像月球的雙胞胎經過地球，就被重力困住了。

As it settles into orbit halfway between Earth and our original moon, it yanks violently at the oceans.

在它進入地球和我們原本的月球的軌道中間時，會對海洋造成猛烈的拉力。

In the real world, this is how our original moon helps generate tides.

在真實世界，這就是我們的月亮幫助製造潮汐的辦法。

So, the second moon would amplify the effect causing peak tides that would be six times higher, eroding shorelines and flooding many of our world's greatest cities including New York, Singapore, and London, gone.

所以第二顆月亮會放大影響，造成比原本大六倍的高峰潮、海岸線被侵蝕、很多大城市會淹水，包括紐約、新加坡、倫敦，都會消失。

But not all destruction would happen on Earth.

但不是所有災難都發生在地球。

The combined pull of the planet and the original moon would also yank on the second moon.

地球和我們原本月球加起來的拉力，也會對第二顆月亮造成猛烈拉力。

The second moon would be caught in a tug of war between earth and the original moon.

第二顆月亮會被困在地球和原本月亮的拔河裡。

The gravitational pull back and forth from both ends would warp the second moon's surface, triggering tremendous volcanic activity flooding the second moon's surface with red hot rivers of lava just like hundreds of the volcanoes you see today on Jupiter's hellish moon, Io.

兩邊的重力造成的拉力會扭曲第二顆月亮的表面，觸發火山活動，讓第二顆月亮的表面充滿又紅又滾燙的岩漿，就像今天在木星的衛星伊奧上看到的好幾百座火山。

But even that's not the end of the spectacle.

但這不是這個情況的結尾。

Right now, our current moon is spiraling away from Earth at 3.8 centimeters a year.

現在，我們的月亮正以一年三點八公分的速率遠離地球。

That's about how fast your fingernails grow.

大概是我們指甲增長的速率。

At the same time, it pulls on the Earth slowing down the planet's rotation which is actually lengthening our days by around one second every 40, 000 years.

同時，它會減緩地球自轉，可以讓一天的時間每四萬年增長一秒。

It may not sound like much, but with two moons in place, it would accelerate this process even more.

聽起來可能沒有很多，但如果同時有兩顆月亮，會更增加這個速度。

Millions of years from now, the day will have grown by 16 percent, lasting longer than 28 hours.

幾百萬年後，一天會增長百分之十六，一天會超過二十八個小時。

Now a little extra time in the day may sound pretty nice, but here's the problem, the extra moon would drift towards the current moon and that's where the real danger comes in.

也許一天多一點時間聽上去不錯，但問題在這，多出來的月亮會往原本的月亮靠近，真正的危險可能會發生。

After millions of years, the two moons would collide.

幾百萬前後，兩顆月亮會相撞。

The impact would be so massive, it would rip the very core of the moons apart.

這造成的影響會非常大，幾乎讓月亮的核心崩壞。

Lava would erupt from their center like a runny egg in space, casting a vivid, red light in the sky on Earth.

岩漿會從核心噴發，就像宇宙中的半生蛋，在地球的天空灑下一道鮮明的紅光。

Meanwhile, debris would go hurtling in all directions where some of it would inevitably strike Earth forming massive craters miles wide.

同時，碎屑會往每個方向噴發，有些一定會往地球來，造成幾哩寬的巨大坑洞。

It would be an apocalypse for all life on Earth.

這對地球上的所有生命都是末日。

And what didn't hit the planet would instead be trapped by Earth's gravity forming a ring of debris around the equator similar to the rings around Saturn.

沒有打進地球的，會被地球的重力困住，繞著赤道形成碎屑的星環，就像繞著土星的環一樣。

But not for long.

但也不會持續太久。

Within just a few years, those chunks would clump together forming one, large, single body.

在幾年之間，那些碎塊會集合在一起，形成一個又大又單一的星體。

Perhaps any life that survived will call it the moon, or maybe something even better.

也許存活下來的生物會稱它為月亮，或給它更好的名字。