Based on what is known, scientists have drawn up a list of the three most likely ultimate fates.
根据已知的信息，科学家列出了三种最有可能发生的终极命运。
- Fate 1: heat death
命运一：热寂- Fate 2: the big rip
命运二：大撕裂- Fate 3: big collapse & big bounce
命运三：大坍缩&大反弹
Fate 1: heat death（命运一：热寂）
Despite the "hot" in the name, the ending is actually dark and cold.
虽然名字里带着“热”，但这个结局其实又黑又冷。
It is based on the second law of thermodynamics: the law of entropy. Entropy is the amount of chaos in a system. Isolated systems tend to go from order to chaos until they reach their most chaotic equilibrium.
它的理论基础是热力学第二定律：熵增定律。熵，指的是系统的混乱程度。孤立系统总是趋向于从有序变得混乱，直到达到最混乱的平衡状态。
Entropy increase is actually pretty easy to understand. Like a glass of water, let's put some red ink in it. At first, the entropy of this cup of liquid is a little bit smaller, a little bit more ordered, because some of it is red, some of it is transparent; Then, the red ink will spread out automatically until the whole cup of liquid becomes uniform, which is the process of entropy increase.
熵增其实很好理解。比如一杯水，让我们朝里面滴一些红墨水。刚开始，这杯液体的熵还比较小，比较有秩序，因为有的地方很红、有的地方很透明；接下来，红墨水会自动扩散开来，直到整杯液体变得均匀为止，这就是熵增过程。
As is the universe. Although the universe is now have various celestial bodies such as stars, planets, and comets. But after a long time, as the universe expands, the celestial bodies will move away from each other, and the stars will gradually run out of fuel and stop glowing. In the following darkness, matter will slowly decay. In the end, even the seemingly indestructible black hole will evaporate and disappear. The temperature of the entire universe is close to 0 K,there is no longer any available energy or heat, and there is no longer any mechanical movement. The universe is immersed in eternal death.
宇宙也是这样的。虽然现在的宇宙拥有恒星、行星、彗星等各种各样的天体；但在很久很久以后，随着宇宙的不断膨胀，天体之间会彼此远离，恒星会逐渐耗尽燃料、停止发光。在接下来的黑暗中，物质会慢慢衰变。到最后，就连看起来坚不可摧的黑洞都会蒸发消失。整个宇宙的温度接近绝对零度，不再有可利用的能源或热量，也不再有任何机械运动。宇宙陷入了永恒的死寂。
Fate 2: the big rip（命运二：大撕裂）
First of all, let's imagine that if we throw a ball into the sky, during the rise of the ball, due to the gravity of the earth, it will surely slow down slowly and eventually fall back to the ground.
首先让我们想象一下，如果朝天空扔一个小球，在小球的上升过程中，由于地球的引力作用，它肯定会慢慢减速，最后掉回到地上。
For a long time, the scientific community believed that the expansion of the universe followed the same principle -- that the expansion of the universe must be slower and slower because of the gravitational action between celestial bodies.
在很长一段时间里，科学界一直认为，宇宙的膨胀也遵循着同样的原理——由于天体间的引力作用，宇宙的膨胀速度肯定是越来越慢。
But in 1998, scientists were surprised to discover that instead of slowing down, the universe was accelerating. This means that in addition to the gravitational pull that pulls them back, there must be some repulsive force driving them away from each other. Scientists have named the source of this mysterious repulsive force "dark energy."
但1998年，科学家惊讶地发现，宇宙不但没有减速，反而正在加速膨胀。这就意味着，除了把天体往回拉的引力之外，肯定还存在着某种排斥力，在驱使着天体彼此远离。科学家把这种神秘排斥力的源头命名为“暗能量”。
According to mathematical models, dark energy could eventually defeat all other forces and accelerate the expansion of the universe indefinitely until a "big rip" occurs in 22 billion years.
根据数学模型，暗能量最终有可能打败一切其它力量，使得宇宙无限制加速膨胀下去，直到220亿年后发生一场“大撕裂”。
First the collapse of the galaxy, then the collapse of the planetary system, followed by the explosion of stars and planets, and finally the collapse of atoms and nuclei in an instant. Thus the universe came to an end in an accelerating frenzy.
首先是星系的瓦解，然后是行星系统的崩溃，紧接着恒星、行星通通爆炸，最后连原子和原子核都会在一瞬间分崩离析。就这样，宇宙在加速的狂暴中迎来大结局。
Fate 3: big collapse & big bounce（命运三：大坍缩&大反弹）
If gravity wins the battle between gravity and repulsive forces, the expansion of the universe could slow down until it stops, and then start shrinking back, like the big bang upside down. This condition is known as "big collapse."
如果在引力和斥力的争夺战中，最终获胜的是引力，那么宇宙的膨胀就有可能减速、直到停止，最后开始往回收缩，收缩过程就像是倒过来的宇宙大爆炸一样。这种情况被称为“大坍缩”。
And when the universe shrinks back to a singularity, there may be a new big bang. Our universe may have been in this perpetual cycle. This cyclical hypothesis is known as the "great bounce".
而当宇宙收缩回一个奇点之后，或许又会迎来一场新的大爆炸。我们的宇宙也许一直处在这种周而复始的循环中。这种循环假说被称为“大反弹”。
