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A New World’s Extraordinary Orbit Points to Planet Nine
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.
Fossil Discoveries Challenge Ideas About Earth’s Start
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 Recalls Discovering Earth’s Tectonic Plates
Jason Morgan developed the theory of plate tectonics in 1967 while working among a critical mass of talented geophysicists at Princeton University.
Eclipse Hunter Reveals the Science That Can Only Be Done in the Dark
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.
What Made the Moon? New Ideas Try to Rescue a Troubled Theory
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.