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Only 170 million years ago, new plankton evolved. Their demand for carbon and calcium permanently transformed the seas as homes for life.
Simple physical principles can be used to describe how rivers grow everywhere from Florida to Mars.
A series of fossil finds suggests that life on Earth started earlier than anyone thought, calling into question a widely held theory of the solar system’s beginnings.
Geochemical signals from deep inside Earth are beginning to shed light on the planet’s first 50 million years, a formative period long viewed as inaccessible to science.