Ancient Superoceans — The Rise And Fall Of Panthalassa And Mirovia

For three hundred million years, seventy percent of Earth's surface was a single, undivided ocean. No continents in the middle. No islands breaking the horizon. Creatures the size of school buses lived in it. It controlled the climate of the entire planet. Its name was Panthalassa. And not one square centimeter of its seafloor survives today — consumed by subduction zones over two hundred million years, its three-hundred-million-year biological record taken back into the mantle and destroyed. We know the surface of Mars better than we know what lived at the bottom of this ocean. Then, in November 2025, scientists published a paper in Science describing thirty thousand fossils found on an Arctic island at Panthalassa's ancient shores — and what they found there rewrote everything we thought we knew about life after the greatest mass extinction in Earth history. SUBSCRIBE    / @chroniclesplanetearth   for deep science told from the geological record outward.