What Causes Lightning? The Answer Keeps Getting More Interesting.
At any given moment, more than 2,000 thunderstorms are occurring around the globe, according to NASA.
据 NASA 称，在任何特定时刻，全球都会发生 2,000 多次雷暴。
Before he changed the way we understand lightning on Earth, Joseph Dwyer studied the weather in more cosmic settings.
在改变我们对地球闪电的理解之前，约瑟夫·德怀尔研究了更宇宙环境中的天气。
Using the sensors on NASA’s Wind satellite , orbiting a million miles away, he watched flares shoot out from the sun and analyzed the particles that stream from the sun’s surface.
他利用美国宇航局风卫星（绕一百万英里运行）上的传感器观察太阳发出的耀斑，并分析从太阳表面流出的粒子。
But when he relocated to Florida around the turn of the millennium, Dwyer felt ready for something new — something he and his students could investigate on their own.
但当德怀尔在世纪之交搬到佛罗里达州时，他觉得自己已经准备好迎接新的事物——他和他的学生可以自己研究的东西。
It didn’t take long before the tropical weather delivered a suitable mystery outside his office window.
没过多久，热带气候就在他办公室的窗外呈现出一个合适的谜团。
“It was like boom, boom, boom outside,” Dwyer said.
“外面就像繁荣、繁荣、繁荣，”德怀尔说。
“I looked into it and realized lightning was an unsolved problem.”
“我研究了一下，发现闪电是一个尚未解决的问题。”
Chains of high-energy electron avalanches may very likely be what makes clouds glow, flicker, and flash with gamma rays.
高能电子雪崩链很可能是使云层发光、闪烁和发出伽马射线闪光的原因。
But are they the elusive cause of lightning?
但它们是闪电的难以捉摸的原因吗？
Thunderstorms have captivated humanity for millennia, and yet their inner workings remain deeply mysterious.
数千年来，雷暴一直吸引着人类，但其内部运作方式仍然非常神秘。
Storm clouds are opaque.
风暴云是不透明的。
They’re dangerous to approach.
接近它们很危险。
And they’re too big to fit in a lab.
而且它们太大，无法放入实验室。
Inquisitive researchers have been sending kites, balloons, and rockets up into them for nearly three centuries, and they’ve learned a lot.
近三个世纪以来，好奇的研究人员一直在向它们发射风筝、气球和火箭，他们学到了很多东西。
But every time lightning lovers get closer to the action, they discover major gaps in their understanding.
但每当闪电爱好者更接近这个动作时，他们就会发现自己的理解存在重大差距。
For the past 50 years, researchers have focused on one particular gap: How does the jagged channel of white-hot air we call a lightning bolt get started?
过去 50 年来，研究人员一直关注一个特定的空白：我们称之为闪电的锯齿状白热空气通道是如何开始的？
Recently, the field has experienced a sort of renaissance as researchers — many of them astrophysics refugees like Dwyer — have devised new ways to pierce the clouds.
最近，随着研究人员（其中许多是像德怀尔一样的天体物理学难民）发明了穿透云层的新方法，该领域经历了某种复兴。
They’ve taken a slew of instruments built to study violent cosmic events and trained them on the brutality of terrestrial thunderstorms.
他们携带了大量用于研究剧烈宇宙事件的仪器，并对它们进行了地面雷暴的残酷训练。
They’ve seen lightning shooting out X-rays as it zigs and zags, spotted flickering glows of gamma rays coming from thunderclouds, and, very recently, detected hints of bolts traveling in unexpected directions.
他们看到闪电在蜿蜒曲折时射出 X 射线，发现了来自雷雨云的伽马射线的闪烁光芒，最近还发现了闪电朝意想不到的方向行进的迹象。
Joseph Dwyer pioneered lightning research by turning instruments designed to study violent cosmic events toward thunderstorms.
约瑟夫·德怀尔（Joseph Dwyer）开创了闪电研究的先河，他将旨在研究剧烈宇宙事件的仪器转向雷暴。
No one has put all the pieces together, but a new understanding of lightning is taking shape.
没有人把所有的碎片整合在一起，但对闪电的一种新的理解正在形成。
The fearsome flashes look less and less like the supersize electric sparks that physicists once imagined them to be.
这些可怕的闪光看起来越来越不像物理学家曾经想象的超大电火花。
While electricity plays a central role, lightning bolts are formed and shaped by the whole physics canon — from cosmic blasts to particle physics.
虽然电起着核心作用，但闪电是由整个物理经典（从宇宙爆炸到粒子物理学）形成和塑造的。
In particular, triggering a bolt seems to require extreme events more typically associated with supernovas, black holes, and particle colliders than with fluffy clouds.
特别是，触发闪电似乎需要极端事件，这些极端事件通常与超新星、黑洞和粒子对撞机相关，而不是与蓬松的云相关。
“There is a growing consensus in the field that high-energy processes play a critical role in lightning initiation,” said Caitano da Silva , an atmospheric physicist at New Mexico Tech.
新墨西哥理工学院的大气物理学家凯塔诺·达席尔瓦说：“该领域越来越多的人认为高能过程在闪电引发中发挥着关键作用。”
“It’s an exciting time to be in this field.”
“进入这个领域是一个激动人心的时刻。”
When lightning bolts split the sky, the ancient Greeks, Scandinavians, and Hindus saw flashes of divine warfare.
当闪电划破天空时，古希腊人、斯堪的纳维亚人和印度教徒看到了神圣战争的闪光。
And when thunderclaps rattled their chests, the Chinese felt a deity punishing wrongdoers.
当雷霆轰鸣在胸口时，中国人感到神明在惩罚不法之徒。
Today, the power of thunderstorms still leaves people awestruck.
时至今日，雷暴的威力仍然让人们惊叹不已。
“I grew up watching these large cold fronts coming in with a lot of lightning” in Brazil, da Silva said.
达席尔瓦说：“我从小就看着这些巨大的冷锋伴随着大量闪电袭来”。
“I grew terrified of it.”
“我开始害怕它了。”
With fear comes fascination.
恐惧伴随着迷恋。
Yet despite centuries of exploration, fascinated physicists like da Silva are still asking the same question that the ancients did: How does lightning begin?
然而，尽管经过了几个世纪的探索，像达席尔瓦这样着迷的物理学家仍然在问古人同样的问题：闪电是如何开始的？
For a time, researchers thought they had an answer.
有一段时间，研究人员认为他们找到了答案。
As physicists demystified electricity in the 18th and 19th centuries, they learned how to make sizable sparks on command: pile up electric charge on one metal ball, bring a second nearby, and a spark leaps between them.
当物理学家在 18 世纪和 19 世纪揭开电的神秘面纱时，他们学会了如何根据命令产生大量火花：在一个金属球上积累电荷，将第二个金属球放在附近，火花就会在它们之间跳跃。
When researchers eventually worked out the structure of matter, they understood why.
当研究人员最终弄清楚了物质的结构时，他们明白了原因。
The separated charges generate an electric field between the balls.
分离的电荷在球之间产生电场。
When the electric field reaches a critical strength — roughly 3 million volts per meter — the air starts to come undone.
当电场达到临界强度（大约每米 300 万伏）时，空气开始瓦解。
The field flings loose electrons into neighboring atoms, where they knock more electrons loose.
电场将松散的电子抛入邻近的原子，在那里它们将更多的电子撞松。
Like snow on a steep mountain slope, the electrons “avalanche,” heating up the air until it glows.
就像陡峭山坡上的雪一样，电子“雪崩”，加热空气直至发光。
Benjamin Franklin linked sparks in the lab with lightning in the sky in his famous kite-flying experiment in 1752.
本杰明·富兰克林在 1752 年著名的放风筝实验中将实验室中的火花与天空中的闪电联系起来。
And for the next 200 years, investigators believed that what happened in storm clouds was exactly the same as what happened between their metallic spheres, just on a larger scale.
在接下来的 200 年里，研究人员相信，暴风云中发生的情况与金属球之间发生的情况完全相同，只是规模更大。
The mystery of lightning seemed solved.
闪电之谜似乎已经解开。
But when physicists graduated from kites to rockets and truck-size weather balloons in the mid-20th century, they found a problem.
但当物理学家在 20 世纪中叶从风筝转向火箭和卡车大小的气象气球时，他们发现了一个问题。
Clouds do have electric fields; tiny ice crystals rub against each other like socks against a carpet, and crystals with extra electrons tend to pile up at the bottom of the clouds.
云确实有电场；微小的冰晶相互摩擦，就像袜子摩擦地毯一样，带有额外电子的晶体往往会堆积在云层底部。
But these fields are weak.
但这些领域都很薄弱。
Typical thunderstorms have just a tenth the electric juice needed to spark, and the strongest fields ever measured reach just a third of the critical intensity.
典型的雷暴只有十分之一的电能量才能产生火花，而有史以来测量到的最强磁场也只有临界强度的三分之一。
Yet according to NASA satellites there are more than 2,000 thunderstorms across the globe at any given moment — an observation as puzzling as avalanches thundering down bunny slopes.
然而，根据 NASA 卫星的数据，全球任何特定时刻都会发生 2,000 多场雷暴——这一观察结果就像雪崩从兔子坡上轰然冲下一样令人费解。
“You have to increase the electric field all the way above the conventional breakdown threshold,” said Michael Stock , a researcher at the Cooperative Institute for Severe and High-Impact Weather Research and Operations at the University of Oklahoma.
俄克拉荷马大学恶劣和高影响天气研究与运营合作研究所的研究员迈克尔斯托克说：“你必须将电场一直增加到传统击穿阈值以上。”
“But that doesn’t seem to happen in nature.”
“但这在自然界中似乎不会发生。”
A visible bolt means the air has broken down into a mess of hot, charged subatomic debris.
可见的闪电意味着空气已经分解成一团热的、带电的亚原子碎片。
So either something has supercharged the electric field, pushing it past the critical threshold, or some other process must break down the air molecules.
因此，要么有某种东西使电场增压，使其超过临界阈值，要么有其他过程必须分解空气分子。
The question is: what?
问题是：什么？
In 1752, Benjamin Franklin conducted his famous kite experiment, as depicted in this c.
1752 年，本杰明·富兰克林进行了他著名的风筝实验，如图所示。
1816 painting by Benjamin West.
本杰明·韦斯特 1816 年绘画。
This experiment established the connection between lightning and electricity.
这个实验建立了闪电和电之间的联系。
One clue comes again from Franklin.
富兰克林再次提供了一条线索。
He observed that sharp tips are more likely to start or receive a spark.
他观察到，锋利的尖端更有可能产生或接收火花。
Physicists now understand that this happens because pointed conductors enhance the nearby electric field.
物理学家现在了解到，发生这种情况是因为尖头导体增强了附近的电场。
In the 1960s and 1970s, physicists in Florida and France started intentionally setting off lightning bolts by firing small rockets with sharp points into storm clouds.
在 20 世纪 60 年代和 1970 年代，佛罗里达州和法国的物理学家开始通过向暴风云发射带有尖头的小型火箭来故意引发闪电。
A wire would unspool behind the rocket and guide the bolt to the ground.
一根电线会在火箭后面解开，并将螺栓引导到地面。
Most storm clouds don’t have rocket-mounted darts to help them spark, but they do have ice crystals, some of which can exceed the size of a pencil eraser.
大多数风暴云没有安装在火箭上的飞镖来帮助它们产生火花，但它们确实含有冰晶，其中一些冰晶的大小可能超过铅笔橡皮擦的大小。
These ice chunks, which are also conductors, can stretch into shards.
这些冰块也是导体，可以拉伸成碎片。
Physicists estimated that sufficiently lengthy ice shards could boost the field strength by a factor of 10 or more, and that a number of these so-called hydrometeors acting together could do even better.
物理学家估计，足够长的冰碎片可以将场强提高 10 倍或更多，并且许多所谓的水凝物一起作用可以做得更好。
Once again, the mystery seemed solved.
谜团似乎再次解开了。
Then physicists started looking at storms from space and learned that thunderclouds were stranger than they had imagined.
然后物理学家开始从太空观察风暴，发现雷雨云比他们想象的更奇怪。
In 1994, a satellite searching for extreme deep-space explosions happened to pick up flashes of gamma rays coming from thunderclouds, often alongside lightning.
1994年，一颗寻找极端深空爆炸的卫星碰巧捕捉到来自雷雨云的伽马射线闪光，通常与闪电一起出现。
Gamma rays are the most energetic type of light rays, typically marking the last gasp of a dying star or the cataclysmic clap of two neutron stars.
伽马射线是能量最高的光线类型，通常标志着垂死恒星的最后一口气或两颗中子星的灾难性拍击。
They are not something you’d expect to come out of a cloud, no matter how many sharp ice chips it had.
它们不是你想象的从云中冒出来的东西，无论它有多少锋利的冰片。
Something was afoot in the fast and intense realm of subatomic particles.
在亚原子粒子的快速而强烈的领域里，有什么东西正在酝酿之中。
This was around the time that Dwyer witnessed the booming Floridian lightning storms and learned about their mysterious origins.
就在那时，德怀尔目睹了佛罗里达州闪电风暴的蓬勃发展，并了解了它们的神秘起源。
As an astrophysicist, he knew about the subatomic realm.
作为一名天体物理学家，他了解亚原子领域。
He was familiar with the work of the Nobel laureate C.T.R.
他熟悉诺贝尔奖获得者 C.T.R. 的工作。
Wilson, who had hypothesized that a “relativistic” electron moving at close to the speed of light would barely feel any drag from atoms in the air.
威尔逊假设，以接近光速运动的“相对论”电子几乎不会感受到空气中原子的任何阻力。
(Da Silva likens it to a bullet ripping through a flurry of snowflakes.) A sufficiently speedy electron in an electric field could therefore “run away” faster and faster.
（达席尔瓦将其比作一颗子弹穿过一片雪花。）因此，电场中速度足够快的电子可以越来越快地“逃跑”。
Dwyer knew that a Russian physicist, Aleksandr Gurevich, had shown in 1992 that such a runaway electron could unleash a cascade of perhaps 100,000 electrons, akin to the avalanches that initiate sparks in the lab but playing out over hundreds to thousands of meters.
德怀尔知道，俄罗斯物理学家亚历山大·古列维奇 (Aleksandr Gurevich) 在 1992 年证明，这种失控电子可以释放出大约 100,000 个电子的级联，类似于在实验室中引发火花的雪崩，但会持续数百到数千米。
And he also knew that when these relativistic, runaway electrons bounced off air molecules, they could emit gamma rays.
他还知道，当这些相对论性的失控电子从空气分子反弹时，它们会发射伽马射线。
Lightning is common in Florida.
闪电在佛罗里达州很常见。
This strike hit the launchpad of the Space Shuttle Challenger at Kennedy Space Center on Aug.
这次袭击于 8 月 17 日击中了肯尼迪航天中心挑战者号航天飞机的发射台。
30th 1983.
1983 年 30 日。
By themselves, these extreme subatomic affairs didn’t seem to be abundant enough to account for the brilliant gamma rays lighting up storm clouds.
就其本身而言，这些极端的亚原子事件似乎不足以解释照亮暴风云的明亮伽马射线。
But then Dwyer imagined a baroque process that could allow one avalanche to set off another, and another, and another, all right on top of each other.
但随后德怀尔想象了一种巴洛克式的过程，可以让一场雪崩引发另一场雪崩，然后再引发一场雪崩，然后再引发另一场雪崩。
According to Dwyer’s process, when one electron in the avalanche collided with an atom, the electron could ricochet and emit a gamma ray.
根据德怀尔的过程，当雪崩中的一个电子与原子碰撞时，电子会弹跳并发射伽马射线。
That gamma ray would transform into an electron and its antimatter twin, a positron.
伽马射线会转变为电子及其反物质孪生正电子。
The cloud’s electric field would push the positron backward close to where the avalanche began.
云的电场会将正电子向后推到雪崩开始的地方。
There it could crash into another atom, setting off another avalanche, which would make more gamma rays, more positrons, more avalanches, and so on, until you got a flash visible from orbit.
在那里它可能会撞上另一个原子，引发另一场雪崩，这会产生更多的伽马射线、更多的正电子、更多的雪崩，等等，直到你从轨道上看到闪光。
“It’s like taking a microphone and sticking it next to a speaker,” said Dwyer , who is now at the University of New Hampshire.
“这就像把麦克风贴在扬声器旁边，”现在在新罕布什尔大学工作的德怀尔说。
“It can get really loud quick.”
“声音很快就会变得很大。”
The stack of runaway relativistic avalanches could explain the gamma rays.
失控的相对论雪崩堆栈可以解释伽马射线。
And it could also contribute to lightning initiation.
它还可能有助于引发闪电。
As the avalanche cascades, electrons pile up at the front while leaving positively charged ions in their wake — boosting the cloud’s electric field.
当雪崩级联时，电子在前面堆积，同时在其尾迹中留下带正电的离子，从而增强了云的电场。
In computer simulations, Dwyer showed that this chain of events amplified avalanches, radiated gamma rays, and ramped up the electric field.
在计算机模拟中，德怀尔表明，这一系列事件放大了雪崩，辐射了伽马射线，并增强了电场。
Around the same time, detailed simulations of ice shards revealed how sharp they were likely to get — not very sharp — which also began to weaken the hydrometeor theory.
大约在同一时间，对冰碎片的详细模拟揭示了它们可能变得多么尖锐——不是很尖锐——这也开始削弱水凝物理论。
So, were Dwyer’s runaway relativistic avalanches really happening inside clouds?
那么，德怀尔失控的相对论雪崩真的发生在云层内部吗？
And could this boost the electric field enough to produce lightning?
这能否增强电场足以产生闪电？
His colleagues were divided.
他的同事们意见不一。
To trigger lightning, researchers fire a small rocket with a thin, grounded metal wire into a charged thundercloud.
为了触发闪电，研究人员将一枚带有细接地金属线的小型火箭发射到带电的雷雨云中。
The wire initiates a lightning strike on command.
电线根据命令启动雷击。
Researchers needed to get closer to the action.
研究人员需要更接近这一行动。
In July 2023, daredevil physicists outfitted a high-altitude NASA plane with gamma-ray detectors and flew it straight over the core of some of the most ferocious storms on the planet — tropical storms in the Gulf of Mexico, the Caribbean, and Central America.
2023 年 7 月，勇敢的物理学家为美国宇航局的一架高空飞机配备了伽马射线探测器，并将其直接飞越了地球上一些最猛烈风暴的核心——墨西哥湾、加勒比海和中美洲的热带风暴。
The plane reached stratospheric perches that “most people would like to avoid at all costs,” da Silva said.
达席尔瓦说，飞机到达了“大多数人都想不惜一切代价避免”的平流层高点。
The campaign was called ALOFT , an acronym made in part from other acronyms.
该活动被称为 ALOFT，是部分由其他缩写词组成的缩写词。
Its observations delivered the biggest bonanza of new data in a generation.
它的观察提供了一代人中最大的新数据财富。
Storm clouds, ALOFT revealed , are bubbling cauldrons emitting all sorts of gamma rays that are too faint to see from space.
ALOFT 透露，风暴云是冒泡的大锅，发出各种伽马射线，这些伽马射线太微弱，从太空中看不到。
The project confirmed the soft glows and sudden flashes around lightning that space-based instruments had also detected.
该项目证实了天基仪器也检测到了闪电周围的柔和光芒和突然闪光。
But ALOFT also detected that clouds flash even when no lightning is visible.
但 ALOFT 还发现，即使看不到闪电，云也会闪烁。
Most curiously, they also flicker.
最奇怪的是，它们还会闪烁。
“They discovered there’s a whole zoo of other phenomena,” said Ute Ebert , a lightning physicist at Eindhoven University of Technology in the Netherlands.
荷兰埃因霍温理工大学的闪电物理学家乌特·埃伯特 (Ute Ebert) 说：“他们发现还有很多其他现象。”
One person who wasn’t completely surprised by the ALOFT observations was Dwyer.
德怀尔 (Dwyer) 是一位对 ALOFT 的观察结果并不完全感到惊讶的人。
In anticipation of the ALOFT team’s announcement, he had rerun his simulations to predict what their gamma-ray detector would see as it flew above the storms.
在 ALOFT 团队宣布这一消息之前，他重新运行了模拟，以预测他们的伽马射线探测器在风暴上方飞行时会看到什么。
He had long known that the relativistic avalanches unavoidably piled up in a flickering pattern, so he calculated exactly what kind of flicker the particle collisions would produce.
他很早就知道相对论雪崩不可避免地会以闪烁的模式堆积起来，因此他准确地计算了粒子碰撞会产生什么样的闪烁。
Both teams presented their findings in San Francisco at the American Geophysical Union’s annual meeting in December 2023, and the results lined right up — the strongest evidence yet that Dwyer’s subatomic collisions are playing out inside real thunderstorms.
两个团队于 2023 年 12 月在旧金山举行的美国地球物理联盟年会上展示了他们的发现，结果一致——这是迄今为止最有力的证据，表明德怀尔的亚原子碰撞正在真实的雷暴中发生。
The NASA ALOFT mission used a high-altitude ER-2 aircraft (left) with pilots (right) flying directly over tropical thunderstorms to detect high-energy particles and radiation associated with lightning.
NASA ALOFT 任务使用一架高空 ER-2 飞机（左）和飞行员（右）直接飞越热带雷暴，以探测与闪电相关的高能粒子和辐射。
Now other theorists are building upon this theory.
现在其他理论家正在这个理论的基础上发展。
Last summer, Victor Pasko , an electrical engineer at Pennsylvania State University, studied the chain of events set off under other circumstances, such as higher electric fields, and found that in these cases too avalanches can pile up and initiate lightning, lending additional support to the whole framework.
去年夏天，宾夕法尼亚州立大学的电气工程师维克多·帕斯科（Victor Pasko）研究了在其他情况下（例如更高的电场）引发的一系列事件，发现在这些情况下雪崩也会堆积并引发闪电，从而为整个框架提供了额外的支持。
“It’s consolidating this idea that the energetic electrons are playing a role here,” da Silva said.
达席尔瓦说：“这巩固了高能电子在这里发挥作用的观点。”
“Until very recently, essentially just Dwyer was talking about this.”
“直到最近，基本上只有德怀尔在谈论这个问题。”
Chains of high-energy electron avalanches may very likely be making clouds glow, flicker, and flash with gamma rays.
高能电子雪崩链很可能使云层发光、闪烁并发出伽马射线闪光。
But researchers can’t say with certainty that they are also sparking lightning.
但研究人员不能肯定地说它们也在引发闪电。
One puzzle is that lightning seems to start from one point in the cloud, while the avalanches take place over a much larger region.
一个谜题是，闪电似乎是从云中的一点开始的，而雪崩则发生在更大的区域。
The avalanches bring the cloud close to the conditions that are expected to lead to lightning.
雪崩使云层接近预计会导致闪电的条件。
But no one has fully connected them to the triggering of a lightning bolt.
但没有人将它们与闪电的触发完全联系起来。
Even as Dwyer’s theory has gained support, observations from early 2025 have revived yet another theory of lightning creation.
尽管德怀尔的理论获得了支持，但 2025 年初的观测结果又重新启动了另一种闪电产生理论。
In the New Mexico desert, a pair of stations bristling with antennas captured radio waves coming out of a dozen separate lightning strikes.
在新墨西哥州的沙漠中，两个布满天线的基站捕获了十几次单独的雷击中发出的无线电波。
Using this data, Xuan-Min Shao, a researcher at Los Alamos National Laboratory, was able to reconstruct the way the overall current moved during the start of these strikes.
利用这些数据，洛斯阿拉莫斯国家实验室的研究员邵宣民能够重建这些撞击开始时总体电流的移动方式。
He found that something was off.
他发现有些不对劲。
If one of Dwyer’s cascades, or any other process driven purely by the electric field, was seeding the lightning bolt, the proto-bolt would move perfectly in line with the electric field from the very beginning of the process.
如果德怀尔的一个级联或任何其他纯粹由电场驱动的过程正在播种闪电，那么原始闪电将从过程一开始就与电场完美地移动。
But Shao found that in these cases, the two directions were slightly at odds.
但邵发现，在这些情况下，两个方向有些不一致。
In the slant, Shao sees evidence for an extraterrestrial, even extragalactic origin for lightning — a cosmic-ray shower.
在倾斜中，邵看到了闪电起源于外星甚至河外的证据——宇宙射线簇射。
Cosmic-ray showers are the end result of violent events in deep space, such as the expulsion of particles from feeding black holes or stellar explosions that fire off a piece of atomic shrapnel — perhaps a proton from an exploding star, or a denuded iron atom expelled from a supermassive black hole.
宇宙射线簇射是深空剧烈事件的最终结果，例如从黑洞中喷出粒子，或者从恒星爆炸中发射出一块原子弹片——可能是来自爆炸恒星的质子，或者是从超大质量黑洞中喷出的裸露铁原子。
These shards travel billions of light-years across the universe and slam into Earth’s atmosphere.
这些碎片穿越宇宙数十亿光年，撞击地球大气层。
The violent collision sprays a jet of electrons, positrons, and other particles down into a cloud at a random angle.
剧烈的碰撞将电子、正电子和其他粒子的射流以随机角度喷射到云中。
These electrons and positrons could have enough oomph to separate the electrons from their molecules and get an avalanche going, even if the electric field stays well below the critical threshold.
即使电场远低于临界阈值，这些电子和正电子也可能具有足够的力量将电子与其分子分离并引发雪崩。
To some physicists, Shao makes a strong case.
对于一些物理学家来说，邵提出了强有力的论据。
“It has to be mapping the direction of something else, most likely the cosmic-ray ionization,” said David Smith , a physicist at the University of California, Santa Cruz.
“它必须绘制其他东西的方向，很可能是宇宙射线电离，”加州大学圣克鲁斯分校的物理学家大卫·史密斯说。
“I find the data extremely convincing.”
“我发现这些数据非常有说服力。”
Others say it’s too soon to know what to make of the finding.
其他人则表示，现在判断这一发现的意义还为时过早。
Shao’s reconstruction technique isn’t fully established, and cosmic-ray showers are full of poorly understood particle physics.
邵的重建技术尚未完全成熟，宇宙射线簇射中充满了人们知之甚少的粒子物理学。
That makes it tempting to use them as a “magic wand,” said Brian Hare , a physicist at the Netherlands Institute for Radio Astronomy, to fill an otherwise hard-to-explain gap in a mysterious process.
荷兰射电天文学研究所的物理学家布赖恩·黑尔（Brian Hare）表示，这使得人们很容易将它们用作“魔杖”，以填补神秘过程中难以解释的空白。
But if Shao and others start to see more instances of lightning flying askew, that might motivate theorists to work out those details.
但如果邵和其他人开始看到更多闪电倾斜飞行的例子，这可能会促使理论家们解决这些细节。
By capturing radio waves from a dozen individual lightning strikes, Xuan-Min Shao has found evidence that cosmic-ray showers may trigger lightning.
通过捕获十几次闪电的无线电波，邵宣民发现了宇宙射线簇射可能引发闪电的证据。
Los Alamos National Laboratory
洛斯阿拉莫斯国家实验室
“It’s a really cool idea, and there’s a hint that this might be going on,” Dwyer said.
“这是一个非常酷的想法，而且有迹象表明这可能正在发生，”德怀尔说。
“If this mechanism is true, every time you see a lightning flash, there is a physical connection to a dying star somewhere in the galaxy.”
“如果这种机制是正确的，那么每次你看到闪电时，都与银河系某处的一颗垂死恒星有物理联系。”
The last few decades of lightning research have produced a handful of ideas for how nature may coax lightning bolts from clouds with weak electric fields.
过去几十年的闪电研究已经产生了一些关于大自然如何利用弱电场从云中诱导闪电的想法。
And while the theories compete in the scientific literature, they likely collaborate in the real world.
虽然这些理论在科学文献中相互竞争，但它们很可能在现实世界中合作。
Long needles of ice may set off bolts in one cloud while a deluge of electrons producing gamma rays does it in another cloud.
长长的冰针可能会在一个云中引发闪电，而大量产生伽马射线的电子会在另一云中引发闪电。
And multiple mechanisms may work together to push the electric field past the point of no return.
多种机制可能共同作用，将电场推向不可返回的点。
Only with more precise measurements of the gamma rays and radio waves that accompany lightning can researchers hope to determine whether one mechanism, or one combination of mechanisms, is the most common.
只有对伴随闪电的伽马射线和无线电波进行更精确的测量，研究人员才有希望确定一种机制或一种机制组合是最常见的。
But as physicists close in on the mystery of what initiates lightning, they’re once again spotting unexpected occurrences that don’t fit any of the theories.
但随着物理学家越来越接近闪电产生的奥秘，他们再次发现了与任何理论都不相符的意外事件。
There are subtle patterns in the gamma rays ALOFT saw, for instance.
例如，伽马射线 ALOFT 锯中就有微妙的图案。
And over the last few years, a radio telescope array in the Netherlands has been providing some of the sharpest images yet of lightning as it begins to branch out from its starting point.
在过去的几年里，当闪电开始从起点延伸时，荷兰的射电望远镜阵列一直在提供一些迄今为止最清晰的闪电图像。
They show that some parts shoot out quickly, some move relatively slowly, and some sprout needles as they travel.
他们表明，有些部件快速射出，有些部件移动相对较慢，有些部件在移动过程中会长出针状体。
These features suggest that even as explanations get more comprehensive, the case of how lightning really works will keep getting reopened.
这些特征表明，即使解释变得更加全面，闪电真正如何运作的案例仍将不断被重新审视。
“It just gets more and more bizarre the more we look,” Dwyer said.
“我们看得越多，它就变得越来越奇怪，”德怀尔说。
“Clearly our very simple pictures here are really incomplete.”
“显然，我们这里非常简单的图片确实不完整。”
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