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So, dark energy could be something that's currently making the universe expand faster, but it could be something that changes and at at some point, starts to pull the universe back together again.
因此，暗能量可能是目前使宇宙膨胀得更快的东西，但它也可能是发生变化的东西，在某个时候，开始把宇宙重新拉回到一起。
Right now, we know that the universe is expanding, galaxies are getting farther apart from each other.
现在，我们知道，宇宙正在膨胀，星系之间的距离越来越远。
And for a long time, we were trying to measure how quickly that expansion was slowing down.
很长时间以来，我们一直试图测量这种膨胀的速度有多快。
And we figured it should be slowing down because the Big Bang happened in the beginning, that kicked off the expansion, and since then, all the gravity of all the stuff in the universe should be kinda putting on the brakes, kinda pulling things back.
我们认为它应该放缓，因为大爆炸一开始发生时，就带动了宇宙了膨胀，从那时起，宇宙中所有东西的引力应该踩刹车，把事物吸引回来。
For a long time, we didn't know if the gravity would eventually win, or if the expansion was so powerful that everything will be moving away from everything else forever.
在很长一段时间里，我们不知道引力是否能做到这点，又或者膨胀是如此强大，以至于一切都将永远远离其他事物。
And if the gravity were to win, then what would happen is the expansion, at some point, would stop.
如果引力获胜，那么将会有膨胀，在某些时候，也会停止。
And distant galaxies, instead of moving away from us, would start barreling toward us in the future.
而遥远的星系，不是远离我们，而是在未来开始向我们冲来。
And the way that it would look to us is that we would see distant galaxies kinda coming toward us.
在我们看来，这种情况就是我们会看到遥远的星系向我们走来。
We would see collisions of galaxies much more often.
我们会频繁地看到星系的碰撞。
Other galaxies would collide with our galaxy.
其他星系会与我们的星系发生碰撞。
There would be a lot more stuff in the smaller region of space, just everywhere in the universe.
在较小的空间区域内会有更多的东西，就像在宇宙的任何地方一样。
The universe would get much more dense.
宇宙空间密度会更高。
And the thing that would actually get dangerous about that, the first thing that would get dangerous about that is that as the universe is compressing, it's not just compressing like the galaxies, the stars, and stuff like that, it's compressing all of the radiation in the universe as well.
而实际上也会有会变得危险的事情，首先，当宇宙压缩时，它不仅仅是压缩星系、恒星和类似的东西，它还压缩了宇宙中的所有辐射。
And we know that there's background radiation in our universe today that's leftover from the time when the early universe was very hot and dense.
我们知道，今天在我们的宇宙中存在着背景辐射，这是早期宇宙非常热和密集的时候留下的。
It dissipated.
它消散了。
It sort of spread out, but that radiation is still out there.
它在消散，但这种辐射仍存在。
And so, if you're compressing the universe, you're bringing all that radiation back into a smaller space.
因此，如果压缩宇宙的空间，就会把所有的辐射带回一个更小的空间。
And so, you're moving toward being back in that plasma state, you're evolving toward being, the whole universe being hot and dense, and in sort of this roiling plasma.
因此，现在正朝着回到等离子体状态的方向发展，整个宇宙变得又热和密度又高，以大量等离子体的形式存在。
As the universe is compressing, not only is it bringing back all that radiation from the primordial fire, it's also compressing all the radiation from all of the stars that ever burned in the universe.
随着宇宙的压缩，它不仅带回了来自原始火种的所有辐射，它还压缩了来自宇宙中曾经燃烧过的所有恒星的所有辐射。
More and more, any random point in the universe would feel a lot more like being right next to a star.
逐渐地，宇宙中的任何随机点都会感觉到更像是紧挨着一颗恒星。
And all of these high energy processes in the universe that create gamma rays and x-rays, that radiation also would be compressed.
而宇宙中所有这些创造伽马射线和X射线的高能过程，这些辐射也会被压缩。
And so, at some point, as you're evolving toward a Big Crunch scenario, as the universe is compressing, you get to a point when there's so much radiation in the universe, just an empty space, just so much radiation that it's enough to ignite the surfaces of stars.
因此，在某些时候，当朝着大挤压的情景演变时，随着宇宙的压缩，最终会到达一个点，当宇宙中有如此多的辐射，宇宙只是一个空的空间，如此多的辐射足以点燃恒星的表面。
And what I mean by that is that there's so much of this high energy radiation just flowing through the universe, that the outsides of stars start carrying out thermonuclear explosions.
我的意思是，有这么多的高能辐射在宇宙中流动，以至于恒星的外部开始进行热核爆炸。
So stars will start to just burn from the outside in.
因此，恒星将开始从外向内燃烧。
And at that point, you know, it's all over.
此时你知道，一切都结束了。
Nothing can survive conditions like that.
没有什么能在这样的条件下生存。
And you end up with just total destruction.
而最终一切会被彻底毁灭。
That's The Big Crunch.
这就是 “大挤压”。
The only way we can see that happening is if dark energy is so weird that it doesn't just cause expansion, it actually stops, turns around, and causes compression.
我们能看到这种情况发生的唯一途径是，如果暗能量是如此奇怪，以至于它不只是导致膨胀，它实际上停止，反转，并导致压缩。
And because we don't know what dark energy is, we don't know if it's something that can change over time.
因为我们不知道暗能量是什么，所以我们不知道它是否是可以随时间变化的东西。
We don't know if it's on some trajectory.
我们不知道它是否在某种轨迹上。
We can't rule out the idea that it could, at some point, reverse directions.
我们不能排除它可能在某些时候扭转方向。
We think that's probably not going to happen.
我们认为这大概率可能不会发生。
