No, the Protomolecule was always on Phoebe, one of Saturn's moons. Turns out Phoebe was actually the delivery method for the Protomolecule, and accidentally got captured by Saturn ~1 billion years ago. It was meant to hit Earth, when life on Earth had only just started to develop. In Real Life, Phoebe actually did…

When I was reading the books, I pictured Julia and Clarissa as two friends of mine who are sisters and do look very alike, despite their age difference. But I'd have no problem with them making Peaches Julie's twin, so long as it isn't cheesy