Three ways the universe could end - Venus Keus

翻译人员: Yuchen Lu 校对人员: Lipeng Chen

We know about our universe’s past:

我们了解宇宙的过往：

the Big Bang theory predicts that all matter, time, and space

大爆炸原理预测了 所有的物质、时间和空间

began in an incredibly tiny, compact state about 14 billion years ago.

都始于140亿年前的极小极紧密的状态。

And we know about the present:

我们了解宇宙的当下，

scientists’ observations of the movement of galaxies

科学家们对于银河运动的观察

tell us that the universe is expanding at an accelerated rate.

告诉我们宇宙正在加速扩张。

But what about the future?

但是未来呢？

Do we know how our universe is going to end?

我们知道我们的宇宙将会如何终结吗？

Cosmologists have three possible answers for this question,

宇宙学家们关于这个问题有三种可能的回答：

called the Big Freeze,

大冻结、

the Big Rip and the Big Crunch.

大撕裂和大挤压。

To understand these three scenarios,

为了理解这三种设想，

imagine two objects representing galaxies.

请想象一下两个物体代表银河。

A short, tight rubber band is holding them together—

一根橡皮筋将它们定在一起——

that’s the attractive force of gravity.

这就是引力。

Meanwhile, two hooks are pulling them apart—

同时，两个钩子将它们分开——

that’s the repulsive force expanding the universe.

这就是扩展宇宙的斥力。

Copy this system over and over again,

如果这个系统复制下去，

and you have something approximating the real universe.

你就会得到一个近似宇宙的模型。

The outcome of the battle between these two opposing forces

这一对相反作用力的结果

determines how the end of the universe will play out.

决定了宇宙的尽头在哪里。

The Big Freeze scenario is what happens if the force pulling the objects apart

大冻结学说指的是

is just strong enough to stretch the rubber band until it loses its elasticity.

这个拉力刚好大到让皮筋失去弹力。

The expansion wouldn’t be able to accelerate anymore,

这样，宇宙的扩张就不会再加速，

but the universe would keep getting bigger.

但宇宙还是会继续变大。

Clusters of galaxies would separate.

银河系会散开。

The objects within the galaxies–

银河系中的物体——

suns, planets, and solar systems

恒星、行星和星系

would move away from each other,

会远离彼此，

until galaxies dissolved into lonely objects

直到银河系彻底分解，

floating separately in the vast space.

漂浮在广阔的宇宙中。

The light they emit would be redshifted to long wavelengths

它们发出的光会被红移成长波，

with very low, faint energies,

所含的能量很少，很模糊。

and the gas emanating from them would be too thin to create new stars.

它们放出的气体太薄， 无法让人看见星星。

The universe would become darker and colder,

宇宙会变得黑暗寒冷，

approaching a frozen state

趋近于冰冻的状态，

also known as the Big Chill,

这也叫做宇宙大寒，

or the Heat Death of the Universe.

或者热寂。

But what if the repulsive force is so strong

但如果这对斥力非常强大呢？

that it stretches the rubber band past its elastic limit,

大到使皮筋超出弹力极限，

and actually tears it?

然后拉断。

If the expansion of the universe continues to accelerate,

如果宇宙的扩张继续加速，

it will eventually overcome not only the gravitational force –

这个拉力最终不仅会克服重力影响——

tearing apart galaxies and solar systems–

导致银河系和太阳系分离——

but also the electromagnetic, weak, and strong nuclear forces

还会克服强核力和弱核力，

which hold atoms and nuclei together.

这两种力是保持原子和核子的。

As a result,

其结果是，

the matter that makes up stars breaks into tiny pieces.

形成星球的物质会变成细小的碎片。

Even atoms and subatomic particles will be destroyed.

甚至于原子和亚原子颗粒都会被摧毁。

That’s the Big Rip.

这就是大撕裂。

What about the third scenario,

那第三种情况呢？

where the rubber band wins out?

如果是皮筋比较有力量会怎么样？

That corresponds to a possible future

这就对应了一个未来 可能会出现的情况——

in which the force of gravity brings the universe’s expansion to a halt—

重力让宇宙的扩张停止，

and then reverses it.

然后往回收。

Galaxies would start rushing towards each other,

星系会开始互相靠拢。

and as they clumped together

在它们凝结在一起的同时，

their gravitational pull would get even stronger.

它们的重力会变得更加强大。

Stars too would hurtle together and collide.

星球也会互相猛烈碰撞。

Temperatures would rise as space would get tighter and tighter.

温度会随着宇宙变小而升高。

The size of the universe would plummet

宇宙会骤然变小，

until everything compressed into such a small space

直到所有东西都压缩成一个小空间。

that even atoms and subatomic particles would have to crunch together.

甚至原子和亚原子都会被压碎。

The result would be an incredibly dense, hot, compact universe —

宇宙最终会变得稠密，异常得热和紧密，

a lot like the state that preceded the Big Bang.

这与大爆炸之前的状态很相似。

This is the Big Crunch.

这就是大挤压。

Could this tiny point of matter explode in another Big Bang?

这个点上的物质会不会又一次大爆炸？

Could the universe expand and contract over and over again,

宇宙会不会重复地扩张和收缩，

repeating its entire history?

重演整段历史呢？

The theory describing such a universe is known as the Big Bounce.

描述上述现象的原理叫作大反弹。

In fact, there’s no way to tell how many bounces could’ve already happened—

事实上，我们不知道宇宙 已经经过了几次反弹，

or how many might happen in the future.

或者将来会发生几次。

Each bounce would wipe away any record of the universe’s previous history.

每一次反弹都会清除宇宙之前的所有历史。

Which one of those scenarios will be the real one?

这些情况中哪一个是真实的？

The answer depends on the exact shape of the universe,

答案取决于宇宙的准确形状，

the amount of dark energy it holds,

它含有的暗物质的数量，

and changes in its expansion rate.

和它扩张率的变化。

As of now, our observations suggest that we’re heading for a Big Freeze.

到现在为止，我们的观察显示 我们正往大冻结的方向前进。

But the good news is that we’ve probably got about 10 to the 100th power years

但好消息是还要过十的一百次方年，

before the chill sets in —

寒冷才会降临。

so don’t start stocking up on mittens just yet.

所以，先别急着囤手套。