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Mapping the moon

Two NASA probes that spent last year orbiting the moon have returned stunning new geological maps that could help explain how it, Earth, and other planets in our solar system formed.

The probes, named Ebb and Flow, flew identical orbits just miles above the moon’s surface to measure its gravity field. Slight disruptions in their paths—caused by the push
and pull of mountains and craters, some of. them below the surface—revealed that the moon’s crust is far thinner than was thought, and “was absolutely pulverized” by asteroids and comets in the distant past, MIT geophysicist Maria Zuber tells NPR.org. The findings suggest that Mars and Earth were also pummeled, and those bombardments could have opened fissures in Mars’s surface that drained its early oceans, and cracked Earth’s crust to allow gases to escape and form our atmosphere.