Scientists have finally measured the size of neutrinos, and the results have overturned our understanding: they are a thousand times larger than atomic nuclei.
In the world of science, every breakthrough can lead to a new understanding of the universe. Recently, the findings of an international research team on neutrinos have caused ripples like a boulder thrown into a still lake. As a creator who pays close attention to cutting-edge science, I feel a great responsibility to interpret this significant discovery with a rigorous attitude. Today, we will discuss neutrinos - the mysterious particles once thought to be "extremely small," now revealing a "big secret."
1. Neutrinos: Mysterious "Ghost Particles"
In the depths of the microcosm, there is a particle that is omnipresent yet elusive, like a ghost - this is the neutrino. Every second, billions of neutrinos pass through our bodies, even through the entire Earth, without us noticing. This magical phenomenon stems from the unique properties of neutrinos - they hardly interact with other matter. Scientists have speculated that neutrinos can penetrate everything so easily because they are extremely small, even much smaller than atomic nuclei. This belief has been deeply rooted in the scientific community until a recent study completely overturned it.
2.The Foundation of Traditional Understanding: Neutrinos' "Smallness" and "Penetrating Power"
For a long time, neutrinos have been considered the "little guys" of the microcosm. Through various experiments, scientists have found that neutrinos hardly participate in electromagnetic and strong interactions, allowing them to penetrate any matter as if the world were an obstacle-free zone. Once, a scientist humorously remarked that to completely block a beam of neutrinos, one might need a lead plate as thick as 5 light-years. This powerful penetrating power makes neutrinos particularly mysterious in scientific research and has led to a deeply ingrained belief about their size: they must be very small.
However, this belief is not without basis. In past experiments, scientists inferred the size of neutrinos through indirect methods, suggesting they might be much smaller than atomic nuclei. After all, photons - another fundamental particle - also have strong penetrating power but can still be blocked by matter, such as light unable to penetrate a 1-millimeter-thick stone. In comparison, the penetrating power of neutrinos seems to suggest their size is extremely small. This belief has dominated the scientific community until recent research results changed everything.
3.Experimental Breakthrough: The "Big Secret" of Neutrinos is Revealed
On February 12, 2025, the journal Nature published a groundbreaking paper. An international research team of scientists from the United States, France, and Canada, through an experiment called BeEST, successfully measured the size of the electron neutrino for the first time. The experimental results left everyone stunned: the spatial range of the neutrino wave packet is thousand times larger than an atomic nucleus!
The core of this experiment involved using the radioactive decay of beryllium-7 atoms. When a beryllium-7 atom decays, it releases a lithium-7 nucleus and an electron neutrino. According to the principles of quantum mechanics, these two particles form an entangled state, like dancers in a pair, influencing each other's movements. Scientists at the Canadian TRIUMF laboratory cleverly utilized this property, implanting beryllium-7 atoms into superconducting sensors and precisely measuring the energy of lithium-7 at temperatures approaching absolute zero.
During the experiment, scientists had to operate under extremely stringent conditions. The temperature in the laboratory was reduced to near absolute zero to minimize the interference of other particles and ensure the accuracy of the measurements. Each measurement required extremely high precision, as the signal from neutrinos is extremely weak. After countless precise measurements, scientists finally reached a shocking conclusion: the spatial range of neutrinos is at least 6.2 picometers (1 picometer equals one trillionth of a meter), a size that far exceeds that of an atomic nucleus.
4.Overturning Conventional Understanding: Neutrinos' "Size" and "Penetrating Power"
This discovery has completely overturned our traditional understanding of neutrinos. The reason neutrinos can easily penetrate matter is not because they are small but because they do not participate in strong and electromagnetic interactions. In other words, neutrinos' penetrating power is not related to their size but stems from their unique properties. This discovery not only refresh our basic understanding of neutrinos but also causes a great stir in the field of fundamental physics.
Scientists have found that the spatial range of neutrino wave packets is much larger than that of atomic nuclei, meaning that in the microcosm, they are not "little guys" but "big fellows." This significant size contrasts sharply with their powerful penetrating power and has led scientists to re-examine the basic properties of neutrinos. This discovery not only opens new directions for neutrino research but also provides new insights for other fundamental physics studies.
5.Profound Implications: A New Chapter in Neutrino Research
The significance of this measurement is undoubtedly profound. First, it break up our inherent understanding of the size of neutrinos, making us realize that these seemingly intangible particles actually have an "enormous body" beyond imagination. Second, this discovery opens new directions for neutrino research, helping us to delve deeper into understanding the basic properties and interaction mechanisms of neutrinos.
More importantly, as one of the most basic particles in the universe, the revelation of neutrino properties is crucial for exploring major scientific issues such as the evolution of the universe, the formation of stars, the mechanisms of supernova explosions, and the asymmetry of matter and antimatter in the universe. For example, during supernova explosions, a large number of neutrinos are released, and their properties and behavior directly affect the evolution of supernovae. By deeply understanding the size and interaction mechanisms of neutrinos, scientists can better simulate the process of supernova explosions, thereby revealing the origin and evolution of matter in the universe.
In addition, this discovery may also have a profound impact on the Standard Model of particle physics. The Standard Model is one of the cornerstones of modern physics, describing the properties and interactions of fundamental particles. However, some characteristics of neutrinos, such as the origin of their mass and neutrino oscillation phenomena, have never been fully explained by the Standard Model. This discovery about the size of neutrinos may provide new clues for improving the Standard Model.
6.Future Prospects: More Astonishing Discoveries Await
As scientists continue to delve into neutrino research, there is good reason to believe that more surprising discoveries about these "ghost particles" await us. The mysterious veil of neutrinos is gradually being lifted, and each breakthrough gives us a deeper understanding of the microcosm. From the initial "little guys" to today's "big fellows," every "transformation" of neutrinos amazes us.
In future experiments, scientists will continue to explore more secrets of neutrinos. For example, they may further study the interaction mechanisms of neutrinos with other fundamental particles or explore the distribution and behavior of neutrinos in the universe. These studies will not only promote the development of fundamental physics but may also provide new ideas for future technological applications. For instance, the strong penetrating power of neutrinos could be used to develop new detection technologies, helping us better monitor the internal structure of the Earth or detect distant cosmic signals.
In conclusion, the "big secret" of neutrinos has been revealed, but they remain full of mystery. The efforts of scientists allow us to see the wonders of the microcosm and fill us with anticipation for future scientific exploration. As more research is conducted, the mysterious veil of neutrinos will gradually be lifted, and the scientific value they contain will continue to emerge.
Neutrinos can easily penetrate matter not because they are small but because they do not participate in strong and electromagnetic interactions. In other words, neutrinos' penetrating power is not related to their size but stems from their unique properties. This discovery not only refresh our basic understanding of neutrinos but also causes a great stir in the field of fundamental physics.
Scientists have found that the spatial range of neutrino wave packets is much larger than that of atomic nuclei, meaning that in the microcosm, they are not "little guys" but "big fellows." This significant size contrasts sharply with their powerful penetrating power and has led scientists to re-examine the basic properties of neutrinos. This discovery not only opens new directions for neutrino research but also provides new insights for other fundamental physics studies.