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The flux of small near-Earth objects colliding with the Earth

Abstract

Asteroids with diameters smaller than 50–100 m that collide with the Earth usually do not hit the ground as a single body; rather, they detonate in the atmosphere1. These small objects can still cause considerable damage, such as occurred near Tunguska2, Siberia, in 1908. The flux of small bodies is poorly constrained, however, in part because ground-based observational searches pursue strategies that lead them preferentially to find larger objects3. A Tunguska-class event—the energy of which we take to be equivalent to 10 megatons of TNT—was previously estimated to occur every 200–300 years, with the largest annual airburst calculated to be 20 kilotons (kton) TNT equivalent (ref. 4). Here we report satellite records of bolide detonations in the atmosphere over the past 8.5 years. We find that the flux of objects in the 1–10-m size range has the same power-law distribution as bodies with diameters >50 m. From this we estimate that the Earth is hit on average annually by an object with 5 kton equivalent energy, and that Tunguska-like events occur about once every 1,000 years.

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Figure 1: Optical light curve from the 6 June 2002 bolide over the Mediterranean Sea.
Figure 2: Bolide energy calibrations.
Figure 3: The flux of small near-Earth objects colliding with the Earth, for diameters less than 200 m.
Figure 4: The flux of small near-Earth objects colliding with the Earth.

References

  1. Hills, J. G. & Goda, P. Damage from the impacts of small asteroids. Planet. Space Sci. 46, 219–229 (1998)

    Article  ADS  Google Scholar 

  2. Sekanina, Z. Evidence for the asteroidal origin of the Tunguska object. Planet. Space Sci. 46, 191–204 (1998)

    Article  ADS  Google Scholar 

  3. Morrison, D., Chapman, C. R. & Slovic, P. Hazards due to Comets and Asteroids (ed. Gehrels, T.) 59–91 (Univ. Arizona Press, Tucson, 1994)

    Google Scholar 

  4. Shoemaker, E. M. Asteroid and comet bombardment of the Earth. Annu. Rev. Earth Planet. Sci. 11, 461–494 (1983)

    Article  ADS  Google Scholar 

  5. Tagliaferri, E., Spalding, R., Jacobs, C., Worden, S. P. & Erlich, A. Hazards due to Comets and Asteroids (ed. Gehrels, T.) 199–221 (Univ. Arizona Press, Tucson, 1994)

    Google Scholar 

  6. McCord, T. B. et al. Detection of a meteoroid entry into the Earth's atmosphere on February 1, 1994. J. Geophys. Res. 100, 3245–3249 (1995)

    Article  ADS  Google Scholar 

  7. Ceplecha, Z. et al. Meteor phenomena and bodies. Space Sci. Res. 84, 327–471 (1998)

    ADS  CAS  Google Scholar 

  8. Nemtchinov, I. et al. Assessment of kinetic energy of meteoroids detected by satellite-based light sensors. Icarus 130, 259–274 (1997)

    Article  ADS  Google Scholar 

  9. Ceplecha, Z., Spalding, R. E., Jacobs, C. & Tagliaferri, E. Proc. SPIE 2813, 46–56 (1996)

    Article  ADS  Google Scholar 

  10. ReVelle, D. O. A predictive macroscopic integral radiation efficiency model. J. Geophys. Res. 85, 1803–1808 (1980)

    Article  ADS  Google Scholar 

  11. ReVelle, D. O. Meteoroids 2001—Conference Proceedings SP-495 (ed. Warmbein, B.) 513–519 (European Space Agency, Noordijwk, The Netherlands, 2001)

    Google Scholar 

  12. ReVelle, D. O. & Ceplecha, Z. Meteoroids 2001—Conference Proceedings SP-495 (ed. Warmbein, B.) 507–512 (European Space Agency, Noordijwk, The Netherlands, 2001)

    Google Scholar 

  13. Britt, D. & Consolmagno, G. The porosity of dark meteorites and the structure of low-albedo asteroids. Icarus 146, 213–219 (2000)

    Article  ADS  CAS  Google Scholar 

  14. Harris, A. W. in Proc. Asteroids, Comets, Meteors 2002 (Berlin, in the press)

  15. Werner, S. C., Harris, A. W., Neukum, G. & Ivanov, B. A. NOTE: The near-Earth asteroid size-frequency distribution: a snapshot of the lunar impactor size-frequency distribution. Icarus 156, 287–290 (2002)

    Article  ADS  Google Scholar 

  16. Harris, A. W. & Davies, J. K. Physical characteristics of near-Earth asteroids from thermal infrared spectrophotometry. Icarus 142, 464–475 (1999)

    Article  ADS  Google Scholar 

  17. Rabinowitz, D., Helin, E., Lawrence, K. & Pravdo, S. A reduced estimate of the number of kilometre-sized near-Earth asteroids. Nature 403, 165–166 (2000)

    Article  ADS  CAS  Google Scholar 

  18. Halliday, I., Griffin, A. A. & Blackwell, A. T. Detailed data for 259 fireballs from the Canadian camera network and inferences concerning the influx of large meteoroids. Meteoritics 31, 185–217 (1996)

    Article  CAS  Google Scholar 

  19. ReVelle, D. O. Meteoroids 2001—Conference Proceedings SP-495 (ed. Warmbein, B.) 483–498 (European Space Agency, Noordijwk, The Netherlands, 2001)

    Google Scholar 

  20. ReVelle, D. O. Historical detection of atmospheric impacts by large bolides using acoustic-gravity waves. Ann. NY Acad. Sci. 822, 284–302 (1997)

    Article  ADS  Google Scholar 

  21. Levison, H. F. et al. The mass disruption of Oort cloud comets. Science 296, 2212–2215 (2002)

    Article  ADS  CAS  Google Scholar 

  22. Borovicka, J. et al. The Moravka meteorite fall – III: Meteoroid initial size, history and composition. Meteorit. Planet. Sci. (submitted)

  23. Brown, P. et al. An entry model for the Tagish Lake fireball using seismic, satellite and infrasound records. Meteorit. Planet. Sci. 37, 661–675 (2002)

    Article  ADS  CAS  Google Scholar 

  24. ReVelle, D. O., Whitaker, R. W., Armstrong, R. T. . Proc. SPIE 3434, 66–77 (1998)

    Article  ADS  Google Scholar 

  25. Brown, P. et al. The fall of the St Robert meteorite. Meteorit. Planet. Sci. 31, 502–517 (1995)

    Article  ADS  Google Scholar 

  26. Borovicka, J. & Spurný, P. Radiation study of two very bright terrestrial bolides and an application to the comet S–L 9 collision with Jupiter. Icarus 121, 484–510 (1996)

    Article  ADS  Google Scholar 

  27. Brown, P., Whitaker, R. W., ReVelle, D. O. & Tagliaferri, E. Multi-station infrasonic observations of two large bolides: signal interpretation and implications for monitoring of atmospheric explosions. Geophys. Res. Lett. 29, 1–4 (2002)

    Google Scholar 

  28. Stewart, J. S. A near-Earth asteroid population estimate from the LINEAR survey. Science 294, 1691–1693 (2001)

    Article  ADS  Google Scholar 

  29. Morbidelli, A., Jedicke, R., Bottke, W. F., Michel, P. & Tedesco, E. F. From magnitudes to diameters: The albedo distribution of near-Earth objects and the Earth collision hazard. Icarus 158, 329–343 (2002)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We thank the US Department of Defense for making these data available. We also thank A.W. Harris, J. Borovicka and Z. Ceplecha for discussions; A.W. Harris for making available to us LINEAR debiased data before publication; and W. Bottke and R. Jedicke for comments and suggestions that improved an earlier version of this Letter. This work was supported in part by the Canada Research Chair program, and the Natural Sciences and Engineering Research Council of Canada. There is no implied endorsement by the US Department of Defense of factual accuracy or opinion in this paper.

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Brown, P., Spalding, R., ReVelle, D. et al. The flux of small near-Earth objects colliding with the Earth. Nature 420, 294–296 (2002). https://doi.org/10.1038/nature01238

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