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Traffic Timeline & Statistics

Refreshed at 2020 UT on 28 December 2020

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Boundary crossing times and distances at time of observation are interpreted by A/CC from JPL SSD Horizons data. Boundary crossing times should be considered approximate since they can be off by many minutes or even hours, depending on the length of an object's observation time span and other factors. See JPL's Close Approach Tables for nominalvs. minimum passage time and distance estimates. Note that there is no exact boundary for a gravitational sphere of incluence (about 2.41 lunar distances for Earth's own), and ten lunar distances from Earth is a useful arbitrary "bubble" within which to organize this reporting but has no special astronomical importance.

The chart below seems to suggest a flux in how many objects fly near the Earth-Moon system during different times of year. This illusion comes from not having an even distribution of asteroid discovery programs and follow-up observers to counter observational gaps caused by changes in length of night and regional weather as well as by program down times. As it is today, most observers are in the northern hemisphere, and most discoveries are made from Arizona with some help previously from New Mexico and now from Hawaii. There probably are always more objects in Earth's neighborhood than are known, including some traveling in our daytime and twilight skies (radar works in daytime but not for discovery).

Note that the data and statistics here list only objects that are in solar rather than geocentric orbits. This excludes tiny 2006 RH120 (links), which apparently was captured as a temporary natural Earth satellite in 2006, first coming within a distance of ten LD from our planet on April 16th and remaining closer than that until October 20th of the following year. It wasn't discovered until 14 September 2006 and at first it was believed to be a human artifact. It approached Earth four times during these months in temporary orbit: 2.2 LD on Sepember 16th, 1.4 LD on January 3rd, 0.9 LD on March 25th, and 0.7 LD on June 14th. (The Earth's Hill sphere -- the theoretical region within which our planet can retain natural satellites rather than lose them to solar orbit, extends out to about 3.89 LD, which this object was within from November 25th until July 13th.)

All data on this page derived from orbit solutions comes from the NASA JPL Solar System Dynamics (SSD) Group through its Horizons system. All information about optical observations comes from the IAU Minor Planet Center (MPC) and info about radar observations comes from JPL SSD. NASA, JPL, and the MPC are not affilliated with this page or A/CC, and responsibility for the interpretation of this information and its use here rests entirely with A/CC.

timeline 3-year monthly counts chart

Three-Year Chart of Close-Passing Object Monthly Counts
See vertical table below left for counts & click to see complete chart 2007-present

Object counts
less than 10 LD from Earth395678117
inside Earth SOI12161216
less than 1 LD from Moon4567
less than 1 LD from Earth3959
close-passer discoveries40476792
less than 10 LD from Earth60535795
inside Earth SOI14181219
less than 1 LD from Moon4567
less than 1 LD from Earth39310
close-passer discoveries40454580
less than 10 LD from Earth84669273
inside Earth SOI17142017
less than 1 LD from Moon4658
less than 1 LD from Earth9786
close-passer discoveries68475947
less than 10 LD from Earth57538293
inside Earth SOI11152130
less than 1 LD from Moon53314
less than 1 LD from Earth66414
close-passer discoveries34425687
less than 10 LD from Earth35477089
inside Earth SOI8111119
less than 1 LD from Moon5255
less than 1 LD from Earth3347
close-passer discoveries26325571
less than 10 LD from Earth27324642
inside Earth SOI3877
less than 1 LD from Moon1351
less than 1 LD from Earth0332
close-passer discoveries17252818
less than 10 LD from Earth25224139
inside Earth SOI46158
less than 1 LD from Moon2563
less than 1 LD from Earth1283
close-passer discoveries16133132
less than 10 LD from Earth38434671
inside Earth SOI981017
less than 1 LD from Moon44410
less than 1 LD from Earth32511
close-passer discoveries28253154
less than 10 LD from Earth648995103
inside Earth SOI18312535
less than 1 LD from Moon712115
less than 1 LD from Earth8121111
close-passer discoveries52737788
less than 10 LD from Earth10677145129
inside Earth SOI26193731
less than 1 LD from Moon84810
less than 1 LD from Earth1151214
close-passer discoveries9350106100
less than 10 LD from Earth729098101
inside Earth SOI15281825
less than 1 LD from Moon512107
less than 1 LD from Earth6161210
close-passer discoveries63766984
less than 10 LD from Earth63627686
inside Earth SOI14101626
less than 1 LD from Moon35715
less than 1 LD from Earth26413
close-passer discoveries45435369

Neighborhood timeline index by month & year


Maximum daily counts of known objects

Within ten LD of Earth:49 on four days, most recently 22 Oct. 2020 & 21 Oct. 2020
Inside Earth SOI:10 on 18 Sept. 2020
Within one LD of the Moon:4 on six days, most recently 3 Dec. 2020 & 1 Dec. 2020
Inside Moon SOI:1 on seven days, most recently 3 Dec. 2020 & 2 Sept. 2019
Inside Earth-Moon system:3 on eight days, most recently 3 Dec. 2020 & 21 Aug. 2020

Designation Credits 2010-2020

This is a list of observing facilities that have been assigned designation credit since late 2010 for a key early observation of a close-passing (within ten LD) object during its discovery apparition, which may or may not lead to receiving formal discovery credit for that object if and when numbered by the IAU.

Totals20202019201820172016201520142013201220112010Who & where
1870438293224279220849665846423MLS - Mt. Lemmon Survey in Arizona
8797589128739011010474714718CSS - Catalina Sky Survey in Arizona
70912612343115788761382513-PS1 - Pan-STARRS 1 in Hawaii
142335245--111----ZTF - Zwicky Transient Facility in southern California
14142512523-------ATLAS Mauna Loa in Hawaii
111352628157------ATLAS Haleakala in Hawaii
85432814--------PS2 - Pan-STARRS 2 in Hawaii
49--------172012LINEAR in New Mexico
41----16520----Allen/DECam - Lori Allen
18126---------Kiso Obs. in Japan
16------44251La Sagra Obs. in Spain
151123431----SONEAR in Brazil
15---546-----SST Atom Site - Space Surveillance Telescope Atom Site in New Mexico
15-------3651SSS - Siding Spring Survey in New South Wales
8134--------JAXA Janess-G in New South Wales
7-----1-1131Spacewatch 0.9m telescope in Arizona
651---------Bok Tel. - Bok Telescope in Arizona
62-31-------Xuyi Sta. - Purple Mtn. Obs. Xuyi Station in China
5---2111----NEOWISE in Earth polar orbit
5---2--3----ESA OGS - ESA Optical Ground Station in the Canary Islands
431---------JPL SynTrack - JPL SynTrack Robotic Telescope
22----------Burnt Tree Hill Obs.
21--1-------GINOP-KHK in Hungary
2-11--------Mauna Kea in Hawaii
2---11------Steward Mt. Lemmon Sta. - Steward Obs. Mt. Lemmon Station in Arizona
2---1---1---Micheli/Mauna Kea - Marco Micheli
2--------11-Spacewatch 1.8m telescope in Arizona
11----------roving observer
11----------Northolt Branch Obs. in England
1-1---------ISON Byurakan Obs. in Armenia
1-1---------Campo dos Amarais Obs.
1--1--------R. Wainscoat/Mauna Kea - R. Wainscoat
1---1-------Nyukasa Obs. in Japan
1----1------Galad/La Silla - Adrian Galad in Slovakia
1-----1-----SZTE - SZTE Asteroid Program in Hungary
1-----1-----MRO - Magdalena Ridge Obs. in New Mexico
1-----1-----ISON-NMO - ISON New Mexico Obs. in New Mexico
1-----1-----EURONEAR/La Palma - EURONEAR
1-------1---Oukaimeden Obs. in Morocco
1-------1---MASTER-II Tunka in Russia
1--------1--Tenagra II Obs. in Arizona
1--------1--Sandlot Obs. in Kansas
1---------1-Crni Vrh Obs. in Slovenia
1----------1Tholen CFHT - UH/Tholen NEO Follow-Up CFH Telescope in Hawaii

57Total in 2010 = 0.77 objects per day
159Total in 2011 = 0.44 objects per day
209Total in 2012 = 0.57 objects per day
188Total in 2013 = 0.52 objects per day
301Total in 2014 = 0.82 objects per day
302Total in 2015 = 0.83 objects per day
422Total in 2016 = 1.15 objects per day
522Total in 2017 = 1.43 objects per day
518Total in 2018 = 1.42 objects per day
677Total in 2019 = 1.85 objects per day
822Total in 2020 = 2.26 objects per day
4177Total designation credits for the 3724-day period = 1.12 objects per day

Discovery Credits 2007-2010

This is a list of observing facilities that discovered close-passing objects during the 1,387-day period from January 2007 through mid-October 2010, when the Minor Planet Center changed its policy to state that "Discoverers will be defined only when an object is numbered." Few objects that have passed close since 2007 have been numbered, so we have instead implemented a tally (immediately above) of observing facilities assigned designation credit for a key early observation of an object during its discovery apparition, which may or may not result in receiving future formal discovery credit for that object.

Totals2010200920082007Who & where
20440734051CSS - Catalina Sky Survey in Arizona
19850516136MLS - Mt. Lemmon Survey in Arizona
10321233227LINEAR in New Mexico
3221389SSS - Siding Spring Survey in New South Wales
234784Spacewatch 0.9m telescope in Arizona
3111-Spacewatch 1.8m telescope in Arizona
211--La Sagra Obs. in Spain
2--11LONEOS in Arizona
11---NEOWISE in Earth polar orbit
1-1--Wildberg Obs. in Germany
1-1--Taunus Obs. in Germany
1-1--Hibiscus Obs. in Tahiti

128Total in 2007 = 0.35 objects per day
151Total in 2008 = 0.41 objects per day
172Total in 2009 = 0.47 objects per day
120Total in 2010 = 0.41 objects per day
571Total discoveries for the 1387-day period = 0.41 objects per day

Last Observation Credits

A list of observing facilities that have succeeded often in acquiring the last optical data point during an asteroid's apparition, including a count of how many close-passing objects they were last to catch within the 5111-day reporting period, since 1 Jan. 2007.

Totals20202019201820172016201520142013201220112010200920082007Who & where
49319912194532312-------Steward Mt. Lemmon Sta. - Steward Obs. Mt. Lemmon Station in Arizona
46762505149403125273836508--ARO Westfield in Illinois
4347960623321231818241712291820Great Shefford Obs. in England
3513037362817172820272325251523Spacewatch 1.8m telescope in Arizona
343--5105101542610-12120--Tenagra II Obs. in Arizona
3015522204114112011201313152620MLS - Mt. Lemmon Survey in Arizona
222410711413739282410353-Mauna Kea in Hawaii
2094081482117----11---Tholen 2.24m - UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii
206412224262629154452431Mt. John Obs. in New Zealand
1722323122820192196101---PS1 - Pan-STARRS 1 in Hawaii
168----35293725239253-Tholen team/Mauna Kea - David Tholen's team
1621723272320867256----CTIO - Cerro Tololo Inter-American Obs. in Chile
1591723262320867254----Holmes/CTIO - Robert Holmes in Illinois
14219231613146148794621Schiaparelli Obs. in Italy
1093101110788141091045-MRO - Magdalena Ridge Obs. in New Mexico
10556211315----------CSS-Kuiper - Catalina Sky Survey Kuiper Telescope in Arizona
96-----------335013ARO - Astronomical Research Obs. in Illinois
9517251684595132---KPNO - Kitt Peak Natl. Obs. in Arizona
91---1049266-------Apache Point - Apache Point Obs. in New Mexico
90---1048266-------Nault/Apache Point - Kristie Nault
811725168436-1-1---Spacewatch/KPNO - Spacewatch
66592211-1-------Schwarzschild Obs. in Germany
57981213411--11241Spacewatch 0.9m telescope in Arizona
4824912678-------Cerro Paranal in Chile
4426441-24422643CSS - Catalina Sky Survey in Arizona
421313252-3121----ESA OGS - ESA Optical Ground Station in the Canary Islands
3924812661-------Micheli/Paranal - Marco Micheli
3813223-----------Visnjan Obs. in Croatia
3618141--3--------DCT - Discovery Channel Telescope in Arizona
363221-17832331-Sandlot Obs. in Kansas
34-131167231-----Micheli/Mauna Kea - Marco Micheli
34-------3736825SSS - Siding Spring Survey in New South Wales
33-12143211------DECam in Chile
264234411--1--15KLENOT in the Czech Republic
25----23191------Allen/DECam - Lori Allen
237529----------Tholen CFHT - UH/Tholen NEO Follow-Up CFH Telescope in Hawaii
232811----1---1--ZTF - Zwicky Transient Facility in southern California
221264-----------PS2 - Pan-STARRS 2 in Hawaii
211164-----------Northolt Branch Obs. in England
1972--1-2412----St. Pardon de Conques Obs. in France
1852241-11---2--Castelmartini Obs. in Italy
17144211121-----McDonald Obs. in Texas
16493-----------R. Wainscoat/Mauna Kea - R. Wainscoat
16--31313---5---NEOWISE in Earth polar orbit
155361----------ATLAS Mauna Loa in Hawaii
132452----------ATLAS Haleakala in Hawaii
121-422-1------2San Marcello Pistoiese Obs. in Italy
12-----125-31---Trueblood/KPNO - Mark Trueblood

Periods of apparent null activity

When no objects known to be within 10 LD of Earth (italics = future)

0053 UT on 24 June 2016-1820 UT on 25 June 2016=01.72708 days
1.727 days total in 2016
0135 UT on 13 July 2015-2153 UT on 13 July 2015=20.300 hours
0.846 days total in 2015
1504 UT on 30 July 2014-1815 UT on 4 Aug. 2014=05.13264 days
2145 UT on 11 July 2014-1042 UT on 12 July 2014=12.950 hours
0937 UT on 5 July 2014-1150 UT on 7 July 2014=02.09236 days
7.765 days total in 2014
1834 UT on 4 Dec. 2013-0308 UT on 6 Dec. 2013=01.35694 days
0338 UT on 17 Aug. 2013-1714 UT on 17 Aug. 2013=13.600 hours
0633 UT on 15 July 2013-1720 UT on 18 July 2013=03.44931 days
2208 UT on 15 June 2013-0228 UT on 30 June 2013=14.18056 days
2143 UT on 28 May 2013-1924 UT on 2 June 2013=04.90347 days
24.457 days total in 2013
0322 UT on 28 July 2012-1549 UT on 31 July 2012=03.51875 days
0206 UT on 12 July 2012-1047 UT on 22 July 2012=10.36181 days
0122 UT on 6 May 2012-0456 UT on 10 May 2012=04.14861 days
0310 UT on 9 Feb. 2012-1642 UT on 10 Feb. 2012=01.56389 days
19.593 days total in 2012
1855 UT on 28 Nov. 2011-0233 UT on 30 Nov. 2011=01.31806 days
1234 UT on 10 Sept. 2011-0926 UT on 11 Sept. 2011=20.867 hours
0117 UT on 30 Aug. 2011-0823 UT on 2 Sept. 2011=03.29583 days
0901 UT on 4 Aug. 2011-1606 UT on 10 Aug. 2011=06.29514 days
11.778 days total in 2011
2220 UT on 23 Aug. 2010-1736 UT on 24 Aug. 2010=19.267 hours
0154 UT on 13 Aug. 2010-2120 UT on 19 Aug. 2010=06.80972 days
1434 UT on 20 July 2010-1638 UT on 23 July 2010=03.08611 days
0753 UT on 16 June 2010-1800 UT on 23 June 2010=07.42200 days
1035 UT on 4 June 2010-0242 UT on 13 June 2010=08.67153 days
1658 UT on 8 Jan. 2010-2239 UT on 8 Jan. 2010=05.683 hours
27.029 days total in 2010
2246 UT on 1 Aug. 2009-1841 UT on 4 Aug. 2009=02.82986 days
1614 UT on 11 July 2009-1056 UT on 24 July 2009=12.77917 days
0111 UT on 15 June 2009-0851 UT on 21 June 2009=06.31944 days
0227 UT on 16 April 2009-0619 UT on 18 April 2009=02.16111 days
24.090 days total in 2009
1657 UT on 24 Aug. 2008-0914 UT on 31 Aug. 2008=06.67847 days
2235 UT on 2 Aug. 2008-2146 UT on 19 Aug. 2008=16.96597 days
0130 UT on 1 July 2008-2043 UT on 11 July 2008=10.80069 days
34.445 days total in 2008
0014 UT on 3 Dec. 2007-1300 UT on 3 Dec. 2007=12.767 hours
1510 UT on 18 Nov. 2007-1715 UT on 19 Nov. 2007=01.08681 days
2343 UT on 18 Aug. 2007-0713 UT on 28 Aug. 2007=09.31250 days
0339 UT on 31 July 2007-1400 UT on 8 Aug. 2007=08.43125 days
0607 UT on 14 July 2007-0037 UT on 28 July 2007=13.77083 days
1356 UT on 29 June 2007-2350 UT on 1 July 2007=02.41250 days
0405 UT on 17 May 2007-1659 UT on 24 May 2007=07.53750 days
2217 UT on 2 May 2007-0049 UT on 3 May 2007=02.533 hours
2330 UT on 6 April 2007-1858 UT on 7 April 2007=19.467 hours
0643 UT on 7 March 2007-0752 UT on 7 March 2007=01.150 hours
0947 UT on 29 Jan. 2007-1153 UT on 30 Jan. 2007=01.08750 days
45.135 days total in 2007

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