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Time of discovery of asteroids which came closer to Earth than the Moon in 2018

After closest approach: 54 (58.1%)   < 24 hours before: 11 (11.8%)   up to 7 days before: 26 (28.0%)   > one week before: 0 (0.0%)   > 7 weeks before: 0 (0.0%)   > one year before: 2 (2.2%) Other Years 2016, 2017, 2018, 2019, 2020

Below is the list of asteroid close approaches to Earth in 2018.

Timeline of known close approaches less than one lunar distance from Earth

A list of known near-Earth asteroid close approaches less than 1 lunar distance (0.0025696 AU (384,410 km; 238,860 mi)) from Earth in 2018.

For reference, the radius of Earth is approximately 0.0000426 AU (6,370 km; 3,960 mi) or 0.0166 lunar distances.
Geosynchronous satellites have an orbit with semi-major axis length of 0.000282 AU (42,200 km; 26,200 mi) or 0.110 lunar distances. Eight known asteroids (2018 BD, A106fgF, 2018 LA, A107j4q, 2018 PD20, 2018 UA, 2018 WG, and 2018 WV1) are confirmed to have passed within this distance, and poorly-observed asteroids ZB0A262, 2018 DN₄, ZGBE54F, A1080DC 2018 VQ₁₀, ZW87F01, and ZW900BE may have also passed within this distance. While most asteroids on this list are confirmed, well-observed unconfirmed objects with a 50% or greater chance of passing within 1 LD of the Earth are included as well.

The largest asteroid to pass within 1 LD of Earth in 2018 was 2018 AH with an estimated diameter of around 137 meters and an absolute magnitude of 22.5. The fastest asteroid to pass within 1 LD of Earth in 2018 was 2018 GE3 that passed Earth with a velocity with respect to Earth of 29.6 km/s (66,000 mph).

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

  Rows highlighted turquoise indicate objects discovered more than 7 weeks 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)

Warning Times by Size

This sub-section visualises the warning times of the close approaches listed in the above table, depending on the size of the asteroid. The sizes of the charts show the relative sizes of the asteroids to scale. For comparison, the approximate size of a person is also shown. This is based the absolute magnitude of each asteroid, an approximate measure of size based on brightness.

Abs Magnitude 30 and greater

(size of a person for comparison)

Abs Magnitude 29-30

Absolute Magnitude 28-29

Absolute Magnitude 27-28

Absolute Magnitude 26-27

Absolute Magnitude 25-26

Absolute Magnitude less than 25 (largest)

•   After closest approach: 1 (25.0%)
•   < 24 hours before: 0 (0.0%)
•   up to 7 days before: 2 (50.0%)
•   > one week before: 0 (0.0%)
•   > 7 weeks before: 0 (0.0%)
•   > one year before: 1 (25.0%)

Notes

1. For a list of current Earth close approaches see NEO Earth Close Approaches
2. 2018 GE3 passed Earth with a velocity with respect to Earth of 29.6 km/s and was approaching the Sun at 35.9 km/s.
3. Distance from the center of Earth to the center of the object. See the NASA/JPL Solar System Dynamics Glossary: Geocentric. Earth has a radius of approximately 6,400 km.
4. Largest known asteroid to pass so close to Earth since 2002 JE9 in 1971.
5. distance error: 0.0000107 AU, approach range: 0 to 0.0052 LD. Assuming the observations were not made in error, there was a (~9%) this asteroid hit the Earth (Impact path). However, there was no record of an impact reported, so if it did indeed impact Earth, it was likely in an uninhabited region or in the Pacific ocean. (The further west in the impact path, the larger the asteroid would be. If it hit west of Africa or in the Indian ocean, it would have been several meters across and have been recorded.) The asteroid is unconfirmed and will likely never receive a provisional designation.
6. distance error: 0.000305 AU, approach range: 0.037 to 0.27 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
7. 0.00141+0.00156
   −0.00137 AU, approach range: 0.018 to 1.157 LD. There is no chance that it impacted Earth, as the minimum distance (0.018 LD) is still roughly 410 kilometers above Earth's surface.
8. distance error: 0.000347 AU, approach range: 0.047 to 0.32 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
9. 2018 LA was estimated to have an 82% chance of impacting Earth somewhere between the central Pacific ocean and Africa (Impact path Archived 2018-06-13 at the Wayback Machine). Several reports have come from South Africa and Botswana confirming that it did indeed impact in central Africa
10. distance error: 0.00000608 AU, approach range: 0.078 to 0.082 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
11. distance error: 0.000184 AU, approach range: 0.13 to 0.28 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
12. distance error: 0.000296 AU, approach range: 0.40 to 0.63 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
13. distance error: 0.0000651 AU, approach range: 0.085 to 0.136 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
14. distance error: 0.000600 AU, approach range: 0.43 to 0.89 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
15. distance error: 0.0000181 AU, approach range: 0.100 to 0.115 LD.
16. distance error: 0.0000114 AU, approach range: 0.325 to 0.333 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
17. distance error: 0.000583 AU, approach range: 0.017 to 0.46 LD. The asteroid is unconfirmed and will likely never receive a provisional designation. There is no chance of impact as the asteroid was discovered after its closest approach.
18. distance error: 0.000165 AU, approach range: 0.023 to 0.152 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.

Timeline of close approaches less than one lunar distance from the Moon

The number of asteroids listed here are significantly less than those of asteroids that approach Earth for several reasons. Asteroids that approach Earth not only move faster, but are brighter and are easier to detect with modern surveys because:

• Asteroids that come closer to Earth are a higher priority to confirm, and only confirmed asteroids are listed with a lunocentric approach distance.
• Those that closely approach the Moon are frequently lost in its glare, making them harder to confirm. They are similarly hard to discover during the new moon, when the Moon is too close to the Sun to detect asteroids while they are near the Moon.

These factors severely limit the amount of Moon-approaching asteroids, to a level many times lower than the asteroids detected passing as close to Earth.

Notes

1. Distance from the center of the Moon to the center of the object. The Moon has a radius of approximately 1,740 km.
2. distance error: 0.000633 AU, approach range: 0.33 to 0.82 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
3. 0.00128+0.00123
   −0.000241 AU. Approach range: 0.41 to 0.98 LD.
4. distance error: 0.00000167 AU, approach range: 0.9942 to 0.9955 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
5. distance error: 0.000198 AU, approach range: 0.73 to 0.89 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
6. distance error: 0.000194 AU, approach range: 0.58 to 0.73 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
7. distance error: Unknown, Approach range: Unknown. The asteroid is unconfirmed and will likely never receive a provisional designation.
8. distance error: 0.000390 AU, approach range: 0.42 to 0.72 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
9. distance error: 0.000506 AU, approach range: 0.56 to 0.95 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
10. distance error: 0.0000329 AU, approach range: 0.943 to 0.968 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.
11. distance error: 0.0000552 AU, approach range: 0.972 to 1.015 LD. The asteroid is unconfirmed and will likely never receive a provisional designation.

Additional examples

An example list of near-Earth asteroids that passed more than 1 lunar distance (384,400 km or 0.00256 AU) from Earth in 2018.

Statistics

Virtual Impactors

List of asteroids that are listed on the Sentry Risk Table because they have short observation arcs with poorly constrained orbits and have a chance of impacting Earth in 2018. Given a short observation arc, many different orbits fit the observed data. These objects could be millions if not billions of kilometers from Earth on the date of a low probability virtual impactor. For example, 2005 TM₁₇₃ is expected to be 5 AU (700 million km) from Earth in December 2018 around the time of the 3 virtual impactors. 2010 GZ60 was removed from the sentry table in February 2018 after further observations were found by NEOWISE, ruling out any possible impacts.

Cumulatively among the asteroids listed below, there is a roughly 1 in 98,700 chance that any of the asteroids will impact Earth in 2018. Most of this comes from asteroid 2008 US which is only ~2 meters in diameter and had a 1 in 240,000 chance of impact on 18 April 2018.

Also included are asteroids discovered before impact (specifically, 2018 LA) and exceptionally massive fireballs with either an equivalent yield of more than 1 kiloton of TNT or an estimated size of more than 3 meters.

Notes

1. This is a measurement of how far off of the "best fit" orbit the asteroid would have to have for it to hit at this time. Further values from 0 mean that the measured positions of the asteroid used to calculate its orbit would need to be highly inaccurate for it to hit Earth. For reference, 1.0/-1.0=31.7% odds the observations would be this inaccurate, 2.0/-2.0=4.6% odds, 3.0/-3.0=0.27% odds.
2. 2011 CF₆₆ has a cumulative probability of 1 in 38,900,000 (Palermo scale -7.16) of impacting Earth in 2018.
3. 2008 EL₆₈ has a cumulative probability of 1 in 1,200,000 (Palermo scale -5.81) of impacting Earth in 2018.
4. 2009 VZ₃₉ has a cumulative probability of 1 in 13,600,000 (Palermo scale -6.89) of impacting earth in 2018.
5. 2015 HV₁₈₂ has a cumulative probability of 1 in 239,000,000 (Palermo scale -5.10) of impacting Earth in 2018.
6. 2008 EM₆₈ has a cumulative probability of 1 in 3,100,000 (Palermo scale -6.04) of impacting Earth in 2018.
7. 2014 HG₁₉₆ has a cumulative probability of 1 in 268,000,000 (Palermo scale -7.64) of impacting Earth in 2018.
8. 2016 AZ₁₉₃ has a cumulative probability of 1 in 61,300,000 (Palermo scale -6.76) of impacting Earth in 2018.
9. 2008 VS₄ has a cumulative probability of 1 in 339,000,000 (Palermo scale -6.54) of impacting Earth in 2018.
10. 2014 LY₂₁ has a cumulative probability of 1 in 384,000 (Palermo scale -5.53) of impacting Earth in 2018.
11. 2014 HR₁₉₇ has a cumulative probability of 1 in 385,000,000 (Palermo scale -7.74) of impacting Earth in 2018.
12. 2010 VP₁₃₉ has a cumulative probability of 1 in 54,000,000 (Palermo scale -8.24) of impacting earth in 2018.
13. 2005 TM₁₇₃ has a cumulative probability of 1 in 336,000,000 (Palermo scale -6.50) of impacting earth in 2018.
14. 2014 JT₇₉ has a cumulative probability of 1 in 46,300,000 (Palermo scale -7.08) of impacting Earth in 2018.
15. 2010 GZ₆₀ was ruled out as a potential impactor after another observation was found by NEOWISE, improving the orbit enough to determine that it is not a near-earth object

See also

• List of asteroid close approaches to Earth
• List of asteroid close approaches to Earth in 2017
• List of asteroid close approaches to Earth in 2019
• List of bolides (asteroids and meteoroids that impacted Earth)
• Asteroid impact prediction

References

1. "JPL Small-Body Database Browser: (2018 GE3)". Jet Propulsion Laboratory.
2. "JPL Small-Body Database Browser". JPL Solar System Dynamics. NASA Jet Propulsion Laboratory.
3. "MPC Database". IAU Minor Planet Center. International Astronomical Union. Retrieved 1 January 2021.
4. ^ "2005TM173 Ephemerides for December 2018".
5. ^ "Sentry: 2011 CF66 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-28.
6. ^ "Sentry: 2008 EL68 (archived)" (computed on 2017-04-09). Archived from the original on 2018-01-28.
7. ^ "Sentry: 2009 VZ39 (archived)" (computed on 2017-04-09). Archived from the original on 2018-01-29.
8. ^ "Sentry: 2015 HV182 (archived)" (computed on 2017-04-06). Archived from the original on 2017-04-14. Retrieved 2020-03-22.
9. "Sentry: 2008 JD33 (archived)" (computed on 2017-04-06). Archived from the original on 2018-01-29. Retrieved 2021-02-06. {{cite web}}: Check |url= value (help)
10. "Sentry: 2008 EK68 (archived)" (computed on 2017-04-06). Archived from the original on 2018-01-29. Retrieved 2021-02-06. {{cite web}}: Check |url= value (help)
11. "Sentry: 2005 ED224 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
12. ^ "Sentry: 2008 EM68 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
13. "Sentry: 2014 OY391 (archived)" (computed on 2017-04-08). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
14. "Sentry: 2014 MV67 (archived)" (computed on 2017-04-06). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
15. ^ "Sentry: 2014 HG196 (archived)" (computed on 2017-04-08). Archived from the original on 2018-01-29. Retrieved 2020-03-22.
16. ^ "Sentry: 2016 AZ193 (archived)" (computed on 2017-04-06). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
17. "Sentry: 2008 US (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-28. Retrieved 2021-02-06. {{cite web}}: Check |url= value (help)
18. ^ "CNEOS Fireball and Bolide Data".
19. "Sentry: 2008 UY91 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-29. Retrieved 2020-03-22.
20. "Sentry: 2014 HD198 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
21. "Sentry: 2008 LE (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-29.
22. ^ "Sentry: 2008 VS4 (archived)" (computed on 2017-04-08). Archived from the original on 2017-10-20.
23. ^ "Sentry: 2014 LY21 (archived)" (computed on 2017-04-08). Archived from the original on 2018-01-28.
24. "Sentry: 2015 ME131 (archived)" (computed on 2017-04-08). Archived from the original on 2017-07-31.
25. "Sentry: 2015 HW182 (archived)" (computed on 2017-04-08). Archived from the original on 2018-01-29.
26. "Sentry: 2015 HS182 (archived)" (computed on 2017-04-08). Archived from the original on 2013-08-19. Retrieved 2020-09-27. {{cite web}}: Check |url= value (help)
27. "Sentry: 2009 FZ4 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-29. Retrieved 2020-03-22.
28. "Sentry: 2016 JO38 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-29. Retrieved 2020-03-22.
29. "Sentry: 2008 UM1 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
30. ^ "Sentry: 2014 HR197 (archived)" (computed on 2017-04-09). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
31. "Sentry: 2008 VL (archived)" (computed on 2017-04-08). Archived from the original on 2018-01-29. Retrieved 2020-03-22.
32. ^ "Sentry: 2010 VP139 (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-29. Retrieved 2021-02-06. {{cite web}}: Check |url= value (help)
33. "Sentry: 2010 XC (archived)" (computed on 2017-04-07). Archived from the original on 2018-01-28. Retrieved 2021-02-06. {{cite web}}: Check |url= value (help)
34. ^ "Sentry: 2005 TM173 (archived)" (computed on 2017-04-08). Archived from the original on 2017-10-20. Retrieved 2020-03-22.
35. "Sentry: 2010 WW8 (archived)" (computed on 2017-04-09). Archived from the original on 2018-01-28. Retrieved 2020-03-22.
36. ^ "Sentry: 2014 JT79 (archived)" (computed on 2017-04-06). Archived from the original on 2018-01-29. Retrieved 2020-03-22.
37. "Sentry: 2010 GZ60 (archived)" (computed on 2017-04-18). Archived from the original on 2017-10-20. Retrieved 2020-03-22.
38. "Sentry: 2010 MY112 (archived)" (computed on 2017-04-08). Archived from the original on 2018-01-28.
39. "Sentry: 2013 YB (archived)" (computed on 2017-04-08). Archived from the original on 2018-01-28.

External links

• Near-Earth object close approaches ±30 days within 5 LD (JPL)
• Upcoming close approaches to Earth (ESA)
• Table of Asteroids Next Closest Approaches to the Earth (Sormano Observatory)

v t e 2018 in space
« 2017 2019 »
Space probe launches	TESS (lunar flyby; Apr 2018) Queqiao (mission to the Moon; May 2018) InSight / Mars Cube One (mission to Mars; May 2018) Parker Solar Probe (solar space mission; Aug 2018) BepiColombo (mission to Mercury; Oct 2018) Chang'e 4 / Yutu-2 (mission to the Moon; Dec 2018)
Impact events	2018 LA Kamchatka meteor
Selected NEOs	Asteroid close approaches 2010 WC9 2017 VR12 2017 YE5 2017 YZ1 2018 AH 2018 BD 2018 BF3 2018 CB 2018 CC (276033) 2002 AJ129 (505657) 2014 SR339 2018 CF2 2018 CL 2018 CN2 2018 CY2 2018 DV1 2018 GE3 2018 PD20 2018 LF16 2018 WV1 (163899) 2003 SD220
Exoplanets	Gliese 1132 c possible exomoon Kepler-1625b I K2-141b K2-146b K2-148b K2-155d K2-229b K2-239b K2-239c K2-239d K2-288Bb Barnard's Star b (refuted in 2021) EPIC 211945201 b HD 89345 b KELT-21b NGTS-3Ab
Discoveries	LSPM J0207+3331 VVV-WIT-07 MACS J1149 Lensed Star 1 10 moons of Jupiter 541132 Leleākūhonua (announced) Hyperion proto-supercluster 2MASS J18082002−5104378 Farout (2018 VG18) FarFarOut (2018 AG37 first imaged) AT2018hyz SN 2018cow
Novae	V357 Muscae (Nova Muscae) V906 Carinae (Nova Carinae) V392 Persei (Nova Persei)
Comets	C/2017 T1 (Heinze) C/2017 U7 C/2018 C2 (Lemmon) 37P/Forbes 66P/du Toit 64P/Swift–Gehrels 38P/Stephan–Oterma C/2018 F4 (PanSTARRS) C/2018 V1 (Machholz-Fujikawa-Iwamoto) 46P/Wirtanen
Space exploration	Hayabusa2 (asteroid Ryugu arrival; Jun 2018) Kepler retirement (Oct 2018) InSight (Mars landing; Oct 2018) Dawn retirement (Nov 2018) OSIRIS-REx (asteroid Bennu arrival; Dec 2018) Voyager 2 (enters interstellar space; Dec 2018) New Horizons (encounter with 486958 Arrokoth; Dec 2018 / Jan 2019)
Outer space portal 2017 in outer space — 2018 in outer space — 2019 in outer space

• Near-Earth objects in 2018
• Lists of asteroids
• Near-Earth asteroids