BBC: Although neutrons were discovered 79 years ago, some of their basic properties have been difficult to measure precisely. One trick to gain better precision is to create a large number of ultracold, or very slow-moving, neutrons to study. With a refined version of an approach they developed in 2007, Oliver Zimmer of the Institut Laue Langevin (ILL) in Grenoble, France, and colleagues used superfluid helium-4 at a frigid four degrees above absolute zero to trap neutrons at a density of 55 per cubic centimeter. That breaks the previous density record, which was also set at the ILL. Zimmer believes the new approach could bring the neutron density to 1000 per cubic centimeter, which would serve to increase the statistical precision of experiments and help exclude theories beyond the standard model.
The finding that the Saturnian moon may host layers of icy slush instead of a global ocean could change how planetary scientists think about other icy moons as well.
Modeling the shapes of tree branches, neurons, and blood vessels is a thorny problem, but researchers have just discovered that much of the math has already been done.
January 29, 2026 12:52 PM
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