Earth has a group of cosmic stalkers. Known as “co-orbitals,” these small bits of rock have a 1:1 mean motion resonance with Earth. Basically, they take the exact same amount of time to orbit the sun as we do. Astronomers have long believed these objects wandered in from the main asteroid belt between Mars and Jupiter, but recent spectral analysis suggests they better match the space-weathered lunar silicates that make up the moon’s surface. As such, there has been an ongoing debate about whether these cosmic stalkers are actually visitors from the belt or blasted pieces of the moon. A new study, published in Icarus, from researchers Elisa Alessi and Robert Jedicke provides strong hints that the belt is the more likely source—but pretty soon we’ll get a definitive answer from a spacecraft.

Bizarre Venus surface formations (or coronae) are likely key to understanding our twin planet’s heretofore inscrutable interior. Using NASA Magellan spacecraft data from decades past, Anna Gulcher, an Earth and planetary scientist at Germany’s University of Freiburg, has created innovative new 3D models of the largest coronae to better understand Venus’ puzzling geodynamics.

A new study led by researchers at the Institute of Cosmos Sciences of the University of Barcelona (ICCUB) and the Institute of Space Studies of Catalonia (IEEC) reveals how the disks of galaxies like the Milky Way are affected by ancient galactic collisions.