Geologists are investigating the mysterious origins of Earth's buoyant, silica-rich continents, which began appearing approximately four billion years ago. Tim Johnson from Curtin University and his colleagues propose that an intense, sustained barrage of asteroid impacts during the Hadean eon played a critical role in this process. This cosmic bombardment likely kept the early crust sufficiently hot and thin to allow for continental formation. Studying this era is difficult because geological evidence is extremely scarce; the oldest known continental rocks date to 4.03 billion years ago, while some zircon crystals reach back to 4.4 billion years. Current scientific debates center on whether continents formed via plate tectonics at subduction zones or through mantle plumes rising from deep within the planet, similar to the movement of wax in a lava lamp.