Editing Near-Earth object (section)

==== Close approaches ====
{{main|List of asteroid close approaches to Earth}}

{{As of|2019|5}}, only 23 comets have been observed to pass within {{convert|0.1|AU|km mi|abbr=on|lk=off}} of Earth, including 10 which are or have been short-period comets.<ref name="closest-NEC"/> Two of these near-Earth comets, Halley's Comet and [[73P/Schwassmann–Wachmann]], have been observed during multiple close approaches.<ref name="closest-NEC"/> The closest observed approach was 0.0151&nbsp;AU (5.88&nbsp;LD) for [[Lexell's Comet]] on July 1, 1770.<ref name="closest-NEC" /> After an orbit change due to a close approach of Jupiter in 1779, this object is no longer an NEC. The closest approach ever observed for a current short-period NEC is 0.0229&nbsp;AU (8.92&nbsp;LD) for [[55P/Tempel–Tuttle|Comet Tempel–Tuttle]] in 1366.<ref name="closest-NEC"/> Orbital calculations show that [[P/1999 J6 (SOHO)]], a faint [[sungrazing comet]] and confirmed short-period NEC observed only during its close approaches to the Sun,<ref>{{cite journal |last1=Sekanina |first1=Zdenek |last2=Chodas |first2=Paul W. |title=Origin of the Marsden and Kracht Groups of Sunskirting Comets. I. Association with Comet 96P/Machholz and Its Interplanetary Complex |journal=The Astrophysical Journal Supplement Series |volume=151 |issue=2 |pages=551–586 |date=December 2005 |doi=10.1086/497374 |bibcode=2005ApJS..161..551S |s2cid=85442034}}</ref> passed Earth undetected at a distance of 0.0120&nbsp;AU (4.65&nbsp;LD) on June 12, 1999.<ref>{{cite web |title=Small-Body Database Lookup. P/1999 J6 (SOHO) |date=April 16, 2021 |publisher=NASA/JPL |url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1999%20J6&view=OPC |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20250101175145/https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1999%20J6&view=OPC |archive-date=January 1, 2025}}</ref>

In 1937, {{convert|800|m|ft|abbr=on}} asteroid [[69230 Hermes]] was discovered when it passed the Earth at twice the [[Lunar distance|distance of the Moon]].<ref name="RadarHermes">{{cite web |title=Radar observations of long-lost asteroid 1937 UB (Hermes) |publisher=[[University of California, Los Angeles|UCLA]] |url=http://www2.ess.ucla.edu/~jlm/research/NEAs/Hermes/ |access-date=January 26, 2024 |url-status=dead |archive-url=https://web.archive.org/web/20230123110938/http://www2.ess.ucla.edu/~jlm/research/NEAs/Hermes/ |archive-date=January 23, 2023}}</ref> On June 14, 1968, the {{convert|1.4|km|mi|abbr=on}} diameter asteroid [[1566 Icarus]] passed Earth at a distance of {{convert |0.0425 |AU |km |abbr=on |lk=off}}, or 16.5 times the distance of the Moon.<ref name=jpl-close>{{cite web |title=Small-Body Database Lookup. 1566 Icarus (1949 MA) |publisher=NASA/JPL |date=August 4, 2024 |url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1566&view=OPC |access-date=January 3, 2025 |url-status=live |archive-url=https://web.archive.org/web/20250103085945/https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1566&view=OPC |archive-date=January 3, 2025}}</ref> During this approach, Icarus became the first minor planet to be observed using [[radar]].<ref name="Pettengill-1969">{{Cite journal |display-authors=6 |first1=G. H. |last1=Pettengill |first2=I. I. |last2=Shapiro |first3=M. E. |last3=Ash |first4=R. P. |last4=Ingalls |first5=L. P. |last5=Rainville |first6=W. B. |last6=Smith |first7=M. L. |last7=Stone |date=May 1969 |title=Radar observations of Icarus |journal=[[Icarus (journal)|Icarus]] |volume=10 |issue=3 |pages=432–435 |bibcode=1969Icar...10..432P |doi= 10.1016/0019-1035(69)90101-8 |issn=0019-1035}}</ref><ref name="Goldstein-1968">{{Cite journal |last=Goldstein |first= R. M. |date=November 1968 |title=Radar Observations of Icarus |journal=[[Science (journal)|Science]] |volume=162 |issue=3856 |pages=903–904 |bibcode=1968Sci...162..903G |doi=10.1126/science.162.3856.903 |pmid=17769079|s2cid=129644095}}</ref> This was the first close approach predicted years in advance, since Icarus had been discovered in 1949.<ref name="Marsden1998"/> The first near-Earth asteroid known to have passed Earth closer than the distance of the Moon was {{mpl|1991 BA|}}, a {{convert|5|-|10|m|ft|abbr=on}} body which passed at a distance of {{convert|170,000|km|mi|abbr=on}}.<ref>{{cite journal |first1=J. V. |last1=Scotti |first2=D. L. |last2=Rabinowitz |first3=B. G. |last3=Marsden |title=Near miss of the Earth by a small asteroid |journal=[[Nature (journal)|Nature]] |volume=354 |pages=287–289 |date=November 28, 1991 |issue=6351 |doi=10.1038/354287a0|bibcode=1991Natur.354..287S}}</ref> As NEA surveys were enhanced, at least one such object was observed each year from 2001, at least a dozen from 2005, and over a hundred from 2020.<ref name="closest-NEA"/><ref name="NEO-close"/>

As astronomers became able to discover ever smaller and fainter and ever more numerous near-Earth objects, they began to routinely observe and catalogue close approaches.<ref name="closest-NEA"/><ref name="NEO-close"/> {{As of|2024|12}}, the closest approach without atmospheric or ground impact ever detected was an encounter with {{convert|5|-|11|m|ft|abbr=on}} asteroid {{mpl|2020 VT|4}} on November 14, 2020,<ref name="NEO-close"/> with a minimum distance of about {{convert|6750|km|mi|abbr=on}} from the Earth's centre, or about {{convert|380|km|mi|abbr=on}} above its surface.<ref name="EarthSky">{{cite news |first=Eddie |last=Irizarry |title=This asteroid just skimmed Earth's atmosphere |work=[[Earth & Sky|EarthSky]] |date= November 16, 2020 |url=https://earthsky.org/space/asteroid-2020-vt4-skimmed-atmosphere-fri-nov-13-2020 |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20241202233126/https://earthsky.org/space/asteroid-2020-vt4-skimmed-atmosphere-fri-nov-13-2020/ |archive-date=December 2, 2024}}</ref> On November 8, 2011, asteroid {{mpl|(308635) 2005 YU|55}}, relatively large at about {{convert|400|m|ft|abbr=on}} in diameter, passed within {{convert|324930|km|mi|abbr=on}} (0.845 [[lunar distance]]s) of Earth.<ref>{{cite web |title=Small-Body Database Lookup. 308635 (2005 YU55) |date=January 7, 2022 |publisher=NASA/JPL |url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2005YU55&view=OPC |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20250101175145/https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2005YU55&view=OPC |archive-date=January 1, 2025}}</ref> On February 15, 2013, the {{convert|30|m|ft|abbr=on}} asteroid [[367943 Duende]] ({{mp|2012 DA|14}}) passed approximately {{convert|27700|km|mi|abbr=on}} above the surface of Earth, closer than satellites in geosynchronous orbit.<ref name="Duende-BBC">{{cite news |first=Jason |last=Palmer |title=Asteroid 2012 DA14 in record-breaking Earth pass |work=BBC News |publisher=[[BBC]] |date=February 15, 2013 |url=https://www.bbc.com/news/science-environment-21442863 |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20180217085054/http://www.bbc.com/news/science-environment-21442863 |archive-date=February 17, 2018}}</ref> The asteroid was not visible to the unaided eye. This was the first sub-lunar close passage of an object discovered during a previous passage, and was thus the first to be predicted well in advance.<ref name="Duende-predict">{{cite news |first1=Paul |last1=Chodas |first2=Jon |last2=Giorgini |first3=Don |last3=Yeomans |name-list-style=amp |title=Near-Earth Asteroid {{mp|2012 DA|14}} to Miss Earth on February 15, 2013 |date=March 6, 2012 |work=News |publisher=NASA/JPL CNEOS |url=https://cneos.jpl.nasa.gov/news/news174.html |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20171222113153/https://cneos.jpl.nasa.gov/news/news174.html |archive-date=December 22, 2017}}</ref>

{{wide image|File:Objects_between_earth_and_moon.jpg|2250px|Diagram showing spacecraft and asteroids (past and future) between the Earth and the Moon}}