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Astronomers argue that there’s an undiscovered giant planet far beyond the orbit of Neptune. A newly discovered rocky body has added evidence to the circumstantial case for it.
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.
Jason Morgan developed the theory of plate tectonics in 1967 while working among a critical mass of talented geophysicists at Princeton University.
Even in the age of sun-observing satellites, astronomers like Jay Pasachoff still seek out total solar eclipses for the tales they can tell about our sun.
Textbooks say that the moon was formed after a Mars-size mass smashed the young Earth. But new evidence has cast doubt on that story, leaving researchers to dream up new ways to get a giant rock into orbit.