In a monumental step for particle physics, China’s Jiangmen Underground Neutrino Observatory (JUNO), located 700 meters underground in southern Guangdong province, is set to begin gathering data on one of the most elusive subatomic particles neutrinos. The $300 million facility, which has been under construction for years, aims to shed light on some of the biggest mysteries in the universe, including the mass hierarchy of neutrinos and their role in the early stages of cosmic evolution.
JUNO’s centerpiece is a giant spherical detector, surrounded by thousands of light-detecting tubes, encased in a 12-story cylindrical water pool. This sophisticated apparatus will help scientists track and analyze neutrinos, particles generated by nuclear reactions, such as those occurring in the sun or in nuclear power plants.
Neutrinos: The Key to Unlocking the Universe’s Secrets
Neutrinos are tiny, nearly massless particles that pass through matter undetected. Every second, trillions of neutrinos travel through everything, including the human body, without causing any harm. Understanding neutrinos is crucial because they hold the key to many unsolved questions about the universe’s formation and the nature of matter.
One of the primary objectives of JUNO is to determine the mass hierarchy of neutrinos which types of neutrinos are heavier or lighter than others. This breakthrough would provide insights into the fundamental workings of the universe, including subatomic processes that occurred during its earliest moments.
A Global Collaboration in the Quest for Knowledge
JUNO is not a solo effort. Chinese physicists are working with international collaborators from countries like France, Germany, Italy, Russia, and even the United States, despite recent Sino-U.S. tensions. The data collected will come from nearby nuclear power plants in Guangdong, allowing scientists to study neutrinos produced by nuclear reactions in real time for up to six years. JUNO will also observe neutrinos emitted by the sun and those generated by the radioactive decay of elements within Earth’s mantle, providing insights into tectonic activity.
JUNO’s advanced capabilities will give it an edge over other neutrino observatories under construction, including the U.S.-based Deep Underground Neutrino Experiment (DUNE). DUNE, supported by the U.S. Department of Energy (DOE) and Fermilab, is still years away from completion and has been plagued by delays and budget overruns, with its cost ballooning to over $3 billion. JUNO, meanwhile, is on track to begin operations by late 2025, potentially producing results years before its American counterpart.
Politics and Science: Navigating Tensions
Despite the groundbreaking nature of the project, geopolitical tensions between the U.S. and China have complicated collaborations. In 2018-2019, the DOE halted cooperation between U.S. institutions and JUNO, focusing instead on the DUNE project. However, some American scientists remain involved in JUNO through funding from the National Science Foundation (NSF), underscoring the scientific community’s desire to continue pushing boundaries, even in the face of political challenges.
“Around 2018-2019, the U.S. DOE asked all national laboratories not to cooperate with China, so Fermilab was forced to stop working with us,” said Wang Yifang, JUNO’s chief scientist, and project manager. Still, the international spirit of scientific collaboration remains, with Wang and others hopeful that these efforts might foster closer ties despite broader diplomatic differences.
Future Prospects and Challenges
While JUNO’s focus is primarily on neutrino research, the broader implications of such work could revolutionize fields like medical imaging and energy development. The detection of neutrinos from multiple sources, including nuclear reactors and Earth’s mantle, will provide invaluable data to scientists worldwide.
The delicate process of handling this data will involve rigorous analysis from multiple international teams. “We have a protocol to ensure no data is missing,” said Cao Jun, JUNO’s deputy manager. Data will be relayed simultaneously to institutions in Beijing, Russia, France, and Italy to ensure transparency and accuracy.
Despite political tensions, U.S. physicist J. Pedro Ochoa-Ricoux, of the University of California, Irvine, emphasized the importance of scientific cooperation. “Despite any political differences, I believe that through our collaboration on this scientific endeavor, we are setting a positive example that may contribute, even in a small way, to bringing our countries closer together,” he said.