A reduced estimate of the number of kilometre-sized near-Earth asteroids

  title={A reduced estimate of the number of kilometre-sized near-Earth asteroids},
  author={David L. Rabinowitz and E. Helin and K. S. Lawrence and Steven H. Pravdo},
Near-Earth asteroids are small (diameters < 10 km), rocky bodies with orbits that approach that of the Earth (they come within 1.3 AU of the Sun). Most have a chance of approximately 0.5% of colliding with the Earth in the next million years. The total number of such bodies with diameters > 1 km has been estimated to be in the range 1,000–2,000, which translates to an approximately 1% chance of a catastrophic collision with the Earth in the next millennium. These numbers are, however, poorly… 

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