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Ice cores preserve layers of snow, trapped air bubbles, dust and water isotopes. Together these record past temperature, greenhouse gases and atmospheric conditions, in some cases back 800,000 years.
Starter thread · AI-reviewed against its sources
Plate tectonics says Earth's rigid outer shell is broken into moving plates. It was assembled in the 1950s and 1960s from seafloor mapping, magnetic stripes, drilling and earthquake data.
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Sunlight warms Earth's surface, which radiates infrared heat. Greenhouse gases absorb much of it and re-radiate it, slowing heat loss to space and keeping the planet warmer.
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Rivers carry small amounts of dissolved salts that the ocean collects, while evaporation leaves the salt behind and rain keeps rivers diluted. Vents and volcanoes add more.
Starter thread · AI-reviewed against its sources
