While researching some information, I came across the following: "Use of the term accretion disc for the protoplanetary disc thus leads to confusion over the planetary accretion process, although in many cases it may well be that both accretion processes are happening simultaneously (e.g. T Tauri)."

Looking up protoplanetary disk, instead, I discovered the nebular hypothesis , and the following: "At the end of the planetary formation epoch the inner Solar System was populated by 50–100 Moon- to Mars-sized planetary embryos. Further growth was possible only because these bodies collided and merged, a process which took up to 100 million years. These objects would have gravitationally interacted with one another, tugging at each other's orbits until they collided, growing larger until the four terrestrial planets we know today took shape."

Upon reading this, I imagined that while the possibility of a binary planet remains low, it's certainly possible. Instead of requiring a highly unlikely encounter between two planets with sizeable moons, the situation of 50 to 100 planetary embryos made the possibility quite real.

So, with this - have any of your thoughts changed?