Panthalassa was a vast ocean that existed during the late Paleozoic and early Mesozoic eras, around 335 to 175 million years ago. It surrounded the supercontinent Pangaea and played a crucial role in the Earth's geological and climatic history. This ancient ocean was characterized by its immense size and depth, influencing ocean currents and marine life. As Pangaea began to break apart, Panthalassa gradually transformed into the modern oceans we know today, including the Pacific Ocean. Its study helps scientists understand the evolution of Earth's oceans and continents.