Elusive ‘Geoneutrinos’ Are Building a New Map of Earth’s Volatile Interior
Elusive ‘Geoneutrinos’ Are Building a New Map of Earth’s Volatile Interior
神秘的“地球中微子”正在绘制地球动荡内部的新地图
In a laboratory 2 kilometers underground, a crane lowers Matt Depatie, a detector technologist, through a hatch into a white-walled cavern filled with about 7,000 tons of ultrapure water that glows as blue as wiper fluid in the light. “Splashdown,” Depatie says over a radio as he steps into an inflatable raft waiting below.
在地下2公里的实验室里，一台起重机将探测器技术员马特·德帕蒂（Matt Depatie）通过舱口送入一个白墙洞穴。洞穴内充满了约7000吨超纯水，在灯光下闪烁着如雨刮水般湛蓝的光芒。“着水了，”德帕蒂对着无线电说道，随后跨入下方等待的充气筏中。
Normally, the cavern is one of the darkest places on Earth, but today it is lit up for maintenance, offering us a rare chance to see inside. I peer through the hatch at Depatie as he paddles over to examine the submerged experiment. He’s inspecting a house-sized detector built to catch some of the most elusive particles known to physics: neutrinos.
通常情况下，这个洞穴是地球上最黑暗的地方之一，但今天为了维护而灯火通明，让我们难得有机会一窥内部。我透过舱口注视着德帕蒂，他划着船去检查水下的实验装置。他正在检查一个房屋大小的探测器，该探测器旨在捕捉物理学中最难以捉摸的粒子：中微子。
This is the SNO+ neutrino experiment, buried deep within the Creighton mine at Snolab, an underground physics laboratory in Sudbury, Canada. SNO+ consists of an acrylic sphere lined with nearly 10,000 sensitive light detectors and filled with 780 tons of oily liquid scintillator, which flashes when lit up by energetic particles. The water around the device and the rock above it shield the detector from the glare of cosmic radiation, allowing the flickers of less common particle interactions to shine through.
这就是SNO+中微子实验，它深埋在加拿大萨德伯里（Sudbury）的Snolab地下物理实验室——克雷顿（Creighton）矿井中。SNO+由一个丙烯酸球体组成，内衬近10,000个灵敏的光探测器，并填充了780吨油性液体闪烁体，当高能粒子穿过时，它会发出闪光。装置周围的水和上方的岩石屏蔽了宇宙辐射的干扰，使那些罕见的粒子相互作用产生的微光得以显现。
Our whole journey down has been part of the crusade to maintain absolute darkness, even beyond the visible spectrum of light. As we descended the main shaft and walked through a rocky tunnel to the lab, our bodies and clothes collected minute amounts of radioactive radon dust. Before entering the main laboratory space, we tossed our mine clothes, showered, and changed into electric blue jumpsuits and hairnets to minimize the contamination we carried in with us. “The showers aren’t for you,” Depatie said as we changed, “they’re for the science.”
我们整个下行过程都是为了保持绝对黑暗，甚至超出了可见光光谱的范围。当我们沿着主竖井下降并穿过岩石隧道到达实验室时，我们的身体和衣服上沾染了微量的放射性氡尘。在进入主实验室空间之前，我们脱掉了矿工服，淋浴并换上了电蓝色的连体服和发网，以尽量减少我们带入的污染。“淋浴不是为了你们，”德帕蒂在换衣服时说，“是为了科学。”
Such extremes are necessary when you’re trying to catch ghosts—in this case, ghosts that may help reveal the secrets of inaccessible regions deep within the Earth.
当你试图捕捉“幽灵”时，这种极端措施是必要的——在这种情况下，这些“幽灵”可能有助于揭示地球深处那些无法触及区域的秘密。
Neutrinos are the most abundant of all the particles that have mass. But that mass is tiny: just a millionth of the mass of an electron. With such little heft and a neutral electromagnetic charge, the particles hardly ever interact with other matter. Trillions of neutrinos—mostly those produced in the sun—pass through our bodies every second, yet after years of hunting them with detectors such as SNO+, researchers have captured only a few hundred thousand of their precious flashes.
中微子是所有具有质量的粒子中数量最多的。但其质量极小：仅为电子质量的百万分之一。由于质量如此之小且呈电中性，这些粒子几乎从不与其他物质发生相互作用。每秒钟有数万亿个中微子（主要是太阳产生的）穿过我们的身体，然而在用SNO+等探测器搜寻多年后，研究人员仅捕捉到了几十万次它们珍贵的闪光。
Even more elusive—so much so that after decades of searching, scientists have detected only a few hundred of them—are geoneutrinos.
更难以捉摸的是地球中微子（geoneutrinos）——科学家们经过几十年的搜寻，仅探测到了几百个。
Geoneutrinos are produced in processes that heat the interior of the planet. This heat plays a major role in powering the flow of rocks in the mantle, which shapes everything from plate tectonics to Earth’s magnetic field. It comes from two main sources: heat left over from the planet’s formation, and heat produced by the decay of uranium, thorium, and potassium in the rocks of the mantle and crust. Without this second source, Earth would have long since cooled off and become a tectonically dead planet.
地球中微子产生于加热地球内部的过程中。这种热量在驱动地幔岩石流动方面起着重要作用，从而塑造了从板块构造到地球磁场的一切。它主要来自两个来源：地球形成时残留的热量，以及地幔和地壳岩石中铀、钍和钾衰变产生的热量。如果没有这第二个来源，地球早就冷却并成为一颗构造上死寂的行星了。
In counting geoneutrinos, physicists can get a direct measure of Earth’s vital heat-producing elements. “It’s the one thing we do that focuses on the Earth,” said Ryan Bayes, a particle astrophysicist at Queen’s University in Ontario who works on SNO+. “Everything else we do is more focused on what we receive from other places in the universe.”
通过计算地球中微子，物理学家可以直接测量地球至关重要的产热元素。“这是我们所做的唯一专注于地球的研究，”安大略省女王大学（Queen’s University）的粒子天体物理学家、SNO+项目成员瑞安·贝斯（Ryan Bayes）说，“我们所做的其他一切研究，更多是关注我们从宇宙其他地方接收到的信息。”
The first detection of geoneutrinos, by an instrument in Japan called Kamland, was reported in 2005. In 2009, the Borexino detector in Italy reported catching several dozen more. In November 2025, SNO+ reported its first detection, bumping up the number of observed geoneutrinos by about 50.
2005年，日本的Kamland仪器首次报告了地球中微子的探测结果。2009年，意大利的Borexino探测器报告捕捉到了几十个。2025年11月，SNO+报告了其首次探测结果，使观测到的地球中微子数量增加了约50个。
What makes the detections at SNO+ special is the experiment’s location: These are the first geoneutrinos measured in the western hemisphere, offering a new perspective on Earth’s radioactive interior.
SNO+的探测之所以特别，是因为其实验地点：这是首次在西半球测量到的地球中微子，为研究地球的放射性内部提供了新的视角。
Major uncertainties remain in interpreting the results from these experiments, but researchers’ best estimates suggest that each site is measuring a different flux. “It could be that that’s the first hint that the mantle is not uniform,” said Mark Chen, a particle astrophysicist at Queen’s University and director of the SNO+ collaboration.
在解读这些实验结果时，仍存在巨大的不确定性，但研究人员的最佳估计表明，每个地点测量到的通量（flux）各不相同。“这可能是地幔并不均匀的第一个迹象，”女王大学粒子天体物理学家、SNO+合作项目主任马克·陈（Mark Chen）说。
Geochemists have conventionally assumed that radioactive elements are distributed evenly throughout the mantle, because the flowing rock should mix everything together. But the measurements of geoneutrinos in different locations could hint that this is not the case.
地球化学家通常假设放射性元素均匀分布在地幔中，因为流动的岩石应该会将一切混合在一起。但不同地点的地球中微子测量结果可能暗示事实并非如此。
The regions that seem to be producing the most geoneutrinos sit roughly above continent-size blobs of anomalously hot, dense material, known as large low-shear-velocity provinces, or LLSVPs, which seismologists have mapped on either side of the core. One is under Africa, the other under the Pacific Ocean. “There may be deep Earth structures in the mantle that are not understood,” Chen said. “It could be that [they] concentrate some kinds of elements.”
似乎产生最多地球中微子的区域，大致位于大陆大小的异常高温、高密度物质团块上方，这些团块被称为“大型低剪切波速省”（LLSVPs），地震学家已在地球核心两侧绘制出了它们的分布图。一个位于非洲下方，另一个位于太平洋下方。“地幔中可能存在我们尚未理解的深层地球结构，”陈说，“它们可能富集了某些种类的元素。”
Neutrinos could one day offer new insight into the still mysterious origin of these deep structures and, more broadly, the patterns in the mantle that underlie many aspects of the Earth system. “It really would be a way to make a chemical map of the Earth’s interior,” said William McDonough, a geochemist at the Chinese Academy of Sciences who has long been a leading voice in the search for geoneutrinos.
中微子有朝一日可能为这些深层结构仍然神秘的起源提供新的见解，更广泛地说，也能揭示地幔中支撑地球系统许多方面的模式。“这确实将成为绘制地球内部化学地图的一种方式，”中国科学院地球化学家、长期以来在地球中微子搜寻领域处于领先地位的威廉·麦克多诺（William McDonough）表示。
The outstanding question is whether the geoneutrino measurements reveal differences between the areas of mantle below each experiment, or if the imbalance originates in the way the different experiments count their geoneutrinos. Researchers across the board say there’s still so much uncertain.
目前悬而未决的问题是，地球中微子的测量结果是否揭示了各实验下方地幔区域的差异，还是这种不平衡源于不同实验计算地球中微子的方式。各地的研究人员都表示，仍有太多的不确定性。