The universe is bustling with matter and energy.
宇宙充满了物质和能量。
Even in the vast apparent emptiness of intergalactic space, there's one hydrogen atom per cubic meter.
即使星系间一片虚无，一立方米的空间内也存在一个氢原子。
That's not the mention a barrage of particles and electromagnetic radiation passing every which way from stars, galaxies, and into black holes.
更不要说从恒星、星系到黑洞的大量粒子和电磁辐射。
There's even radiation left over from the Big Bang.
甚至还有大爆炸后留下的辐射。
So is there such thing as a total absence of everything?
到底有没有真正空无一物的空间？
This isn't just a thought experiment. Empty spaces, or vacuums, are incredibly useful.
这不仅仅是个思想实验。真空是十分有用的。
Inside our homes, most vacuum cleaners work by using a fan
在我们的家中，吸尘器通过利用风扇
to create a low-pressure relatively empty area that sucks matter in to fill the void.
创造一个低压的相对空旷的区域，把物质吸入来填补这个空间。
But that's far from empty. There's still plenty of matter bouncing around.
但（吸尘器）里面不是真空。仍然有很多物质在里面跳动。
Manufacturers rely on more thorough, sealed vacuums for all sorts of purposes.
制造商依赖封闭真空达到各种目的。
That includes vacuum-packed food that stays fresh longer,
包括真空包装食物，可以保存更久，
and the vacuums inside early light bulbs that protected filaments from degrading.
早期灯泡利用真空来防止灯丝挥发。
These vacuums are generally created with some version of what a vacuum cleaner does
这些真空通常是运用了类似真空吸尘器的原理，
using high-powered pumps that create enough suction to remove as many stray atoms as possible.
通过高压泵的强大吸力去除尽可能多的杂质。
But the best of these industrial processes tends to leave hundreds of millions of atoms per cubic centimeter of space.
但即使利用最好的工业流程，每立方厘米空间也会残留成亿的原子。
That isn't empty enough for scientists who work on experiments, like the Large Hadron Collider,
这还远达不到科学家对实验条件的要求，比如大型强子对撞机，
where particle beams need to circulate at close to the speed of light for up to ten hours without hitting any stray atoms.
离子束接近光速循环，要求在长达十小时中不会碰撞到杂质。
So how do they create a vacuum?
如何创造这样的真空？
The LHC's pipes are made of materials, like stainless steel,
大型强子对撞机由不锈钢构成，
that don't release any of their own molecules and are lined with a special coating to absorb stray gases.
本身不释放任何分子，并且利用特殊涂层吸收杂质气体。
Raising the temperature to 200 degrees Celsius burns off any moisture,
200摄氏度的高温让一切水分瞬间蒸发，
and hundreds of vacuum pumps take two weeks to trap enough gas and debris out of the pipes for the collider's incredibly sensitive experiments.
上百个真空泵用在两周时间里去除气体和杂质，让对撞机的管道中可以进行灵敏度极高的试验。
Even with all this, the Large Hadron Collider isn't a perfect vacuum.
就算这样，大型强子对撞机也不是绝对真空。
In the emptiest places, there are still about 100,000 particles per cubic centimeter.
即使是真空度最高的空间内，每立方厘米仍然有10万个粒子。
But let's say an experiment like that could somehow get every last atom out.
但我们假设这样的一个实验，可以把所有原子都取出来。
There's still an unfathomably huge amount of radiation all around us that can pass right through the walls.
大量辐射仍然存在于我们周围，可以穿透墙壁。

Every second, about 50 muons from cosmic rays, 10 million neutrinos coming directly from the Big Bang,
每秒50个介子来自宇宙射线，1000万个中微子来自大爆炸，
30 million photons from the cosmic microwave background, and 300 trillion neutrinos from the Sun pass through your body.
3000万光子来自宇宙辐射背景，300万亿中微子来自太阳，能够穿透你的身体。
It is possible to shield vacuum chambers with substances, including water, that absorb and reflect this radiation, except for neutrinos.
能够用来屏蔽真空的物质包括水，能够吸收和反射这些辐射，但不包括中微子。
Let's say you've somehow removed all of the atoms and blocked all of the radiation.
现在我们假设所有物质都被清除掉，并且屏蔽了所有辐射。
Is the space now totally empty? Actually, no.
这时的空间是绝对真空吗？并不是。
All space is filled with what physicists call quantum fields.
所有空间都充满了物理学家所谓的量子场。
What we think of as subatomic particles, electrons and photons and their relatives,
亚原子粒子，电子，光子和它们的亲戚们
are actually vibrations in a quantum fabric that extends throughout the universe.
在量子场中震动，整个宇宙都是一样。
And because of a physical law called the Heisenberg Principle,
根据海森堡原理这一物理定律，
these fields never stop oscillating, even without any particles to set off the ripples.
即使没有粒子掀起涟漪，震动也从未停止。
They always have some minimum fluctuation called a vacuum fluctuation.
最小的波动始终存在，这就叫做真空波动。
This means they have energy, a huge amount of it.
这意味着它们蕴含着巨大能量。
Because Einstein's equations tell us that mass and energy are equivalent,
因为爱因斯坦方程认为质量和能量守恒，
the quantum fluctuations in every cubic meter of space have an energy that corresponds to a mass of about four protons.
每立方米空间的量子涨落的能量，相当于大约4个质子的质量。
In other words, the seemingly empty space inside your vacuum would actually weigh a small amount.
也就是说，看似空无一物的空间也有轻微的重量。
Quantum fluctuations have existed since the earliest moments of the universe.
量子涨落在宇宙形成之初就已存在。
In the moments after the Big Bang, as the universe expanded, they were amplified and stretched out to cosmic scales.
当宇宙膨胀的大爆炸时刻，这些震动被放大，并延伸到整个宇宙。
Cosmologists believe that these original quantum fluctuations were the seeds of everything we see today:
宇宙学家认为这些原始的量子波动是我们今天看到的一切事物的起源：
galaxies and the entire large scale structure of the universe, as well as planets and solar systems.
星系和整个大规模宇宙的结构，以及行星和太阳系。
They're also the center of one of the greatest scientific mysteries of our time because according to the current theories,
它们也是我们这个时代最伟大的科学秘密，因为根据目前的理论，
the quantum fluctuations in the vacuum of space ought to have 120 orders of magnitude more energy than we observe.
真空中量子涨落应该比我们能观察的还要多120个数量级。
Solving the mystery of that missing energy may entirely rewrite our understanding of physics and the universe.
揭开能量丢失的秘密，能够让我们对物理和宇宙有新的认识。