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

Nature volume 403, pages 165–166 (2000)Cite this article

Abstract

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 millennium1,2. These numbers are, however, poorly constrained because of the limitations of previous searches using photographic plates. (One kilometre is below the size of a body whose impact on the Earth would produce global effects3.) Here we report an analysis of our survey for near-Earth asteroids that uses improved detection technologies. We find that the total number of asteroids with diameters > 1 km is about half the earlier estimates. At the current rate of discovery of near-Earth asteroids, 90% will probably have been detected within the next 20 years.

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Figure 1: Number of near-Earth asteroids versus absolute magnitude and diameter.

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Acknowledgements

The research described in this paper was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

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Authors and Affiliations

  1. Yale University Physics Department, 266 Whitney Avenue, New Haven, JWG 552, 06511, Connecticut, USA

    David Rabinowitz

  2. Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, 91109, California, USA

    Eleanor Helin, Kenneth Lawrence & Steven Pravdo

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  1. David Rabinowitz
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  2. Eleanor Helin
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  3. Kenneth Lawrence
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  4. Steven Pravdo
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Rabinowitz, D., Helin, E., Lawrence, K. et al. A reduced estimate of the number of kilometre-sized near-Earth asteroids . Nature 403, 165–166 (2000). https://doi.org/10.1038/35003128

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