artist's depiction of planets colliding. While major asteroid and comet impacts have often been devastating for life on Earth, life on Earth wouldn’t be here without impacts that occurred early in our world’s history.  As the story goes, Due to our planet’s position in the solar system and early hotness, it just didn’t start out with the oceans life enjoys today. Exactly when and what delivered all the H2O we enjoy today is an area of ongoing research. One leading theory looked to the early collision between the proto-Earth and a Mars-sized planet called Thea as one possible...