Satoshi Okuzumi

A pebble from a distant asteroid can remember the magnetic field that acted on it billions of years ago. Such pebbles, particles from asteroid Ryugu, were brought to Earth by Japan's Hayabusa2 probe. Inside them, like the needle of an ancient compass, the direction of the magnetic field from the solar system's youth is frozen.

When a giant planet grows, it pulls in gas. Some of that gas swirls around it into a small disk — called a circumplanetary disk. It is in such disks that moons are thought to form. For the planet PDS 70 c, located 370 light-years away, such a disk was directly observed using the ALMA antenna array in the millimeter range.