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This is a list of examples where an asteroid or meteoroid travels close to the Earth. Some are regarded as potentially hazardous objects if they are estimated to be large enough to cause regional devastation.

Near-Earth object detection technology began to improve around 1998, so objects being detected as of 2004 could have been missed only a decade earlier due to a lack of dedicated near-Earth astronomical surveys. As sky surveys improve, smaller and smaller asteroids are regularly being discovered. The small near-Earth asteroids 2008 TC3, 2014 AA, 2018 LA, 2019 MO, 2022 EB₅, 2022 WJ₁, 2023 CX₁, 2024 BX₁, 2024 RW₁, 2024 UQ, and 2024 XA₁ are the only elevem asteroids discovered before impacting into Earth (see asteroid impact prediction). Scientists estimate that several dozen asteroids in the 6–12 m (20–39 ft) size range fly by Earth at a distance closer than the moon every year, but only a fraction of these are actually detected. See also lists dedicated to specific years such as List of asteroid close approaches to Earth in 2023.

Timeline of approaches within one lunar distance

The average distance to the Moon (or lunar distance (LD)) is about 384,400 km (238,900 mi), which is around 30 times the diameter of the Earth. Below are lists of close approaches less than one LD for a given year. (See also near-Earth asteroids and NEO Earth Close Approaches.)

Closest per year

From the list in the first section, these are the closest known asteroids per year that approach Earth within one lunar distance. More than one asteroid per year may be listed if its geocentric distance is within a tenth of the lunar distance, or 0.10 LD. For comparison, since a satellite in a geostationary orbit has an altitude of about 36,000 km (22,000 mi), then its geocentric distance is 0.11 LD (approximately three times the width of the Earth).

The table shows that the years 2016 and 2017 had a total of 13 such close encounters that are known. Of these, eight were undetected until after they'd happened and only one was detected with more than 24 hours' notice. 2018 has fared better so far, with six out of the eight known close encounters being detected beforehand, albeit with less than 24 hours' notice in most cases.

This list does not include any of the hundreds of objects that collided with Earth which were not discovered in advance but were recorded by sensors designed to detect detonation of nuclear devices. Of the objects so detected, 78 had an impact energy greater than that of a 1-kiloton device (equivalent to 1,000 tons of TNT), including 11 which had an impact energy greater than that of a 10-kiloton device, i.e. comparable to the atomic bombs detonated on Hiroshima and Nagasaki in the Second World War.

  Rows highlighted red indicate objects which were not discovered until after closest approach

  Rows highlighted yellow indicate objects discovered less than 24 hours before closest approach

  Rows left white indicate objects discovered 1–7 days before closest approach

  Rows highlighted green indicate objects discovered more than one week before closest approach

  Rows highlighted blue indicate objects discovered more than one year before closest approach, i.e. objects successfully cataloged on a previous orbit, rather than being detected during final approach.

A notable case is the relatively large asteroid Duende, which was predicted nearly a year in advance, coincidentally approaching just a few hours after the unrelated Chelyabinsk meteor, which was unpredicted, but injured thousands of people when it impacted.

Largest per year

From the lists in the first section, these are the largest known asteroids per year that approach Earth within one LD. (More than one asteroid per year may be listed if its size is 100 m  or more.) For comparison, the 1908 Tunguska event was caused by an object about 60–190 m (200–620 ft) in size, while the 2013 Chelyabinsk meteor, which injured thousands of people and damaged buildings when it generated a large airburst over Russia, was estimated to be just 20 m (66 ft) across.

The table shows about 14 events in the decades 1900–2020 involving a body with an upper size estimate of 100 m (330 ft) or more making a close approach to Earth within one LD, with one (the Tunguska object) making impact.

The year 2011 was notable as two asteroids with size 100 m (330 ft) or more approached within one lunar distance.

Fastest per year

The average near-Earth asteroid, such as 2019 VF₅, passes Earth at 18 km/s. The average short-period comet passes Earth at 30 km/s, and the average long-period comet passes Earth at 53 km/s. A retrograde parabolic Oort cloud comet (e=1, i=180°) could pass Earth at 72 km/s when 1 AU from the Sun.

Passed by outside atmosphere

Objects with distances greater than 100 km (62 mi) are listed here, although there is no discrete beginning of space.

Objects < 50 meters

Asteroids smaller than about 50 m (160 ft).

2020 QG—Closest asteroid flyby not to hit Earth, at 2,900 km (1,800 mi); closest approach on 16 August 2020.

Objects > 50 meters

Asteroids larger than about 50 m (160 ft).

Asteroids with large uncertainty regions are not included.

* Asteroid approach did not occur during an observed apparition. Passage is calculated by integrating the equations of motion.

** Only the nominal (best-fit) orbit shows a passage this close. The uncertainty region is still somewhat large due to a short observation arc.

Predicted encounters

Incomplete list of asteroids larger than about 50 m (160 ft) predicted to pass close to Earth (see also asteroid impact prediction and Sentry (monitoring system)):

A list of predicted NEO approaches at larger distances is maintained as a database by the NASA Near Earth Object Program.

** Only the nominal (best-fit) orbit shows a passage this close. The uncertainty region is still somewhat large due to a short observation arc.

Earth-grazers

Objects which enter and then leave Earth's atmosphere, the so-called Earth-grazers, are a distinct phenomenon, inasmuch as entering the lower atmosphere can constitute an impact event rather than a close pass. Earth-grazer can also be short for a body that "grazes" the orbit of the Earth, in a different context.

Animations

Overview

Notes

1. Distance from the center of Earth to the center of the object. See the NASA/JPL Solar System Dynamics Glossary: Geocentric Archived 2013-02-14 at the Wayback Machine. Earth has a radius of approximately 6,400 km.
2. the asteroid is unconfirmed and will likely never receive a provisional designation.
3. Distance error: 0.000420 AU, approach range: 0.016 to 0.25 LD. There was a roughly 2% chance of impact. The asteroid is most likely between 1 and 14 meters across, so would probably be detectable. The asteroid is unconfirmed and will likely never receive a provisional designation.

References

1. "Responding to Potential Asteroid Redirect Mission Targets". Jet Propulsion Laboratory. Archived from the original on 2014-02-26. Retrieved 2014-02-21.
2. Chang, Kenneth (June 14, 2018). "Asteroids and Adversaries: Challenging What NASA Knows About Space Rocks - Relevant Comments". The New York Times. Archived from the original on June 22, 2018. Retrieved July 21, 2018.
3. ^ NASA Staff (10 May 2011). "Solar System Exploration: Planets: Earth's Moon: Facts & Figures". NASA. Archived from the original on 10 February 2014. Retrieved 6 November 2011.
4. "Fireballs". Archived from the original on 2017-03-14. Retrieved 2018-07-23.
5. "Small asteroid detected 4 days after passing as close as satellites". 18 March 2016. Archived from the original on 2016-04-22. Retrieved 2016-04-21.
6. With an arc of 1.5 hours and 6 observations, there is a roughly 40% chance it passed further than 0.1 LD, with a maximum distance of 0.13 LD.
7. Farnocchia, Davide; Chesley, Steven R.; Brown, Peter G.; Chodas, Paul W. (1 August 2016). "The trajectory and atmospheric impact of asteroid 2014 AA". Icarus. 274: 327–333. Bibcode:2016Icar..274..327F. doi:10.1016/j.icarus.2016.02.056.
8. de la Fuente Marcos, C.; de la Fuente Marcos, R.; Mialle, P. (13 October 2016). "Homing in for New Year: impact parameters and pre-impact orbital evolution of meteoroid 2014 AA". Astrophysics and Space Science. 361 (11): 358 (33 pp.). arXiv:1610.01055. Bibcode:2016Ap&SS.361..358D. doi:10.1007/s10509-016-2945-3. S2CID 119251345.
9. Yeomans, Don; Chodas, Paul (4 February 2011). "Very Small Asteroid Makes Close Earth Approach on February 4, 2011". Near-Earth Object Program Office. NASA/JPL. Archived from the original on 2 September 2011. Retrieved 22 February 2013.
10. "Impact Cratering Mechanics". Lunar and Planetary Institute (LPI). Retrieved 2011-09-16.
11. ^ "Closest Approaches to the Earth by Minor Planets". International Astronomical Union/Minor Planet Center. Archived from the original on 14 February 2013. Retrieved 12 February 2013.
12. MPEC 2020-Q51 : 2020 QG, Minor Planet Center, https://www.minorplanetcenter.net/mpec/K20/K20Q51.html, 17 August 2020, accessed 17 August 2020.
13. Newly-discovered asteroid ZTF0DxQ passed less than 1/4 Earth diameter yesterday, making it the closest-known flyby that didn't hit our planet., Tony Dunn, 17 August 2020.
14. Benner, Lance A. M. "2011 MD Goldstone Radar Observations Planning". Asteroid Radar Research. JPL/California Institute of Technology. Archived from the original on 19 February 2013. Retrieved 22 February 2013.
15. Benner, Lance A. M. "2012 DA14 Goldstone Radar Observations Planning". Asteroid Radar Research. JPL/California Institute of Technology. Archived from the original on 15 February 2013. Retrieved 20 February 2013.
16. "NEOs Removed from Impact Risk Tables". Near-Earth Object Program Office. NASA/JPL. Archived from the original on 26 April 2011. Retrieved 17 February 2013.
17. Plait, Phil (25 May 2012). "Small asteroid to buzz Earth on May 28". Discover. Archived from the original on 21 January 2013. Retrieved 16 February 2013.
18. ^ Williams, David R. "Near Earth Object Fact Sheet". Lunar & Planetary Science. NASA Goddard Space Flight Center. Archived from the original on 26 September 2015. Retrieved 17 February 2013.
19. ^ "NEO Earth Close-Approaches (Between 1900 A.D. and 2200 A.D., NEOs with H <=22, nominal distance within 5 LD)". Near-Earth Object Program Office. NASA/JPL. Archived from the original on 13 December 2012. Retrieved 17 May 2015.
20. Benner, Lance A. M. "(214869) 2007 PA8 Goldstone Radar Observations Planning". Asteroid Radar Research. JPL/California Institute of Technology. Archived from the original on 16 February 2013. Retrieved 14 February 2013.
21. Atkinson, Nancy (11 December 2012). "Two Asteroids Will Buzz Past Earth on December 11". Universe Today. Archived from the original on 26 March 2013. Retrieved 12 February 2013.
22. "PHA Close Approaches To The Earth". International Astronomical Union/Minor Planet Center. Archived from the original on 4 November 2011. Retrieved 14 November 2011.
23. NASA, Near Earth Object Program, database NEO Earth Close-Approaches Between 1900 A.D. and 2200 A.D. limited to encounters with reasonably low uncertainty Archived 2013-02-17 at the Wayback Machine (accessed 20 Sept. 2013)
24. Ceplecha, Z. (March 1994). "Earth-grazing daylight fireball of August 10, 1972". Astronomy and Astrophysics. 283 (1): 287–288. Bibcode:1994A&A...283..287C. ISSN 0004-6361.
25. S., Abe; J., Borovička; P., Spurný; P., Koten; Z., Ceplecha; Meteor Network Team in Japan (18–22 September 2006). "Earth-grazing fireball on March 29, 2006". European Planetary Science Congress 2006. Berlin. p. 486. Bibcode:2006epsc.conf..486A. Archived from the original on 28 May 2019. Retrieved 2015-03-14.
26. Borovička, J.; Ceplecha, Z. (April 1992). "Earth-grazing fireball of October 13, 1990". Astronomy and Astrophysics. 257 (1): 323–328. Bibcode:1992A&A...257..323B. ISSN 0004-6361.
27. Spurný, P.; Borovička, J.; Ceplecha, Z.; Shrbený, L. (2008), "Precise Multi-Instrument Data on 45 Fireballs Recorded over Central Europe in the Period 2006-2008" (PDF), Asteroids, Comets, Meteors 2008 held July 14–18, 2008 in Baltimore, Maryland, vol. 1405, p. 8217, Bibcode:2008LPICo1405.8217S, archived (PDF) from the original on 2016-03-03, retrieved 2015-03-14

External links

• Sentry Risk Table – Jet Propulsion Laboratory
• "PHA Close Approaches To The Earth" – Minor Planet Center
• "NEO Earth Close Approaches" – NASA/JPL's Near-Earth Object Program Office
• "NEO Earth Close-Approaches" (Between 1900 A.D. and 2200 A.D., NEOs with H <=22, nominal distance within 5 LD) – NASA/JPL's Near-Earth Object Program Office
• "Near Earth Asteroids (NEAs): A Chronology of Milestones" – International Astronomical Union
• NEODyS-2 – Near Earth Objects Dynamic Site sponsored by ESA
• TECA Table of asteroids next close approaches to the Earth – Sormano Astronomical Observatory
• SAEL Small Asteroids Encounter List – Sormano Astronomical Observatory
• E.A.R.N. – European Asteroid Research Node
• Upcoming Close Approaches (< 0.10 AU) of NEOs to the Inner Planets - Andrew Lowe using Solex 11
• Earth's Busy Neighborhood – HohmannTransfer
• NASA Astronomy Picture of the Day: Earthgrazer: The Great Daylight Fireball of 1972 (2 March 2009)

• Lists of asteroids
• Near-Earth asteroids
• Planetary defense