Tom Foale

A basic accounting rule in physics says whenever a particle collision creates a baryon—something like a proton or neutron that consists of three particles called quarks—it must simultaneously create a similar antibaryon. Such “baryon number conservation” implies the amount of nuclear matter in the universe is fixed. However, physicists have never determined where within a baryon the conserved number resides. For decades, the textbook answer has been simple. Each quark carries a baryon number of 1/3 and each antiquark carries a baryon number of –1/3. Because a collision can only ever make quark-antiquark pairs, the total baryon number cannot change. However, a recently published study suggests the baryon number is not carried by the quarks, but instead resides in an agglomeration of particles called gluons that bind the quarks together and is called a baryon junction. Learn more: scim.ag/3UyAU0c

Naegleria fowleri is a harmless pond-dweller—unless it ends up in the nose of a human swimmer. Once inside, the amoeba can crawl along nerve fibers in the nasal cavity and through little openings in the skull until it reaches the brain. Once there, it can cause an infection that is almost universally fatal, earning it the frightening moniker the “brain-eating amoeba.” Exactly why N. fowleri, which normally feeds on bacteria, exhibits this behavior has long been unclear. But a recent study suggests a possible reason: The parasite loves to seek out tight spaces. This “claustrophilic” behavior may help it find its prey—and explain why it occasionally ends up deep in the human brain. Learn more: scim.ag/4bXCOgP

Over decades, lunar orbiters have amassed evidence that the Moon’s polar craters hold stores of water, locked up as ice. But no mission has directly sampled these frozen deposits to determine how much ice is there, how it is distributed, or how it got there in the first place. China will soon launch Chang’e-7, a robotic mission designed to address those questions by sending a thruster-powered “hopping” probe into a crater near the lunar south pole, among the coldest, darkest places in the Solar System. Learn more: scim.ag/4x9Q7Da

From the island’s coasts to its sloping mountain ranges, Puerto Rico’s tropical forests teem with biodiversity. But these forests are even more diverse than they appear at first glance: When it comes to how they use water, trees in Puerto Rico are surprisingly individualistic. A recently published study reveals that in these forests, two trees belonging to the same species can vary wildly in how they transport, manage, and store water, depending on how dry it is in their specific habitats. The findings suggest Puerto Rico’s tropical forests may be more resilient to drought than once thought and point toward better ways to model forests’ responses to future climate change. Learn more: scim.ag/4xBhwh7

A basic accounting rule in physics says whenever a particle collision creates a baryon—something like a proton or neutron that consists of three particles called quarks—it must simultaneously create a similar antibaryon. Such “baryon number conservation” implies the amount of nuclear matter in the universe is fixed. However, physicists have never determined where within a baryon the conserved number resides. For decades, the textbook answer has been simple. Each quark carries a baryon number of 1/3 and each antiquark carries a baryon number of –1/3. Because a collision can only ever make quark-antiquark pairs, the total baryon number cannot change. However, a recently published study suggests the baryon number is not carried by the quarks, but instead resides in an agglomeration of particles called gluons that bind the quarks together and is called a baryon junction. Learn more: scim.ag/4hxQTFl