We are entering a new era of planetary seismology, building on the strong foundation of terrestrial studies and propelled by the success of missions such as InSight on Mars. Lunar initiatives such as the Farside
The majority of stars are orbited by one or more small close-in planets. These planets, which are 1-4 Earth radii and have orbits interior to that of Mercury, do not have solar system counterparts. Thousands of such exoplanets are now known. One of the most startling
