When fundamental particles are heavier or lighter than expected, physicists’ understanding of the universe can tip into the unknown. A particle that is just beyond its predicted mass can unravel scientists’ assumptions about the forces that make up all of matter and space. But now, a new precision measurement has reset the balance and confirmed scientists’ theories, at least for one of the universe’s core building blocks.

Nearly every object we interact with in our lives has a mass, but where does this mass come from? Modern physics says matter acquires its mass from interaction with a physical vacuum—it is not an empty space, but contains a complex structure. Investigating the system of a meson—a composite particle made of a quark, an elementary particle, and its anti-matter, anti-quark—bound to an atomic nucleus, a mesic nucleus, provides precious insight into the vacuum structure, or mass generation mechanism. Scientists are now one step closer to further understanding the origin of mass thanks to new experimental results on a completely new type of mesic nucleus.

In a new Nature Physics publication, University of Amsterdam researchers introduce human-made materials that spring to life. These ‘metamaterials’ don’t just learn to change shape, but can autonomously adapt their shape-changing strategy, perform reflex actions and move around like living systems do.