Earth-crosser asteroid

An Earth-crosser asteroid is a Near-Earth asteroid whose orbit crosses that of Earth. The known numbered Earth-crossers are listed here. Buried in the list is one peculiar asteroid: 3753 Cruithne, whose orbit enjoys an unusual special relationship with Earth's. Those Earth-crossers whose semi-major axes are smaller than Earth's are Aten asteroids; the remaining ones are Apollo asteroids. See also the Amor asteroids.
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