Abstract
We will address several questions to which the models presented earlier do not provide obvious answers: Why does Venus have no moon? Why is Mercury’s core so large relative to the planet’s size? The proposed explanations involve specific events, the probability of which seems low. Given these unresolved problems and explanations that are sometimes rather contrived, it is legitimate to ask whether a radically different model—such as that of pebble accretion—might offer a new understanding of the formation of terrestrial planets. We will show that, unfortunately, this model also faces several compositional, chronological, and dynamical constraints. However, pebble accretion may have played an important role in the re-accretion of debris produced during collisions between planetesimals.
