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Traffic Timeline & Statistics

Refreshed at 1819 UT on 13 October 2019

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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 Earth47395678
inside Earth SOI6121612
less than 1 LD from Moon4456
less than 1 LD from Earth4395
close-passer discoveries33404767
less than 10 LD from Earth67605357
inside Earth SOI17141812
less than 1 LD from Moon6456
less than 1 LD from Earth7393
close-passer discoveries50404445
less than 10 LD from Earth64846692
inside Earth SOI24171420
less than 1 LD from Moon12465
less than 1 LD from Earth10978
close-passer discoveries56684759
less than 10 LD from Earth57575382
inside Earth SOI13111521
less than 1 LD from Moon4533
less than 1 LD from Earth5664
close-passer discoveries35344156
less than 10 LD from Earth33354770
inside Earth SOI581111
less than 1 LD from Moon2525
less than 1 LD from Earth1334
close-passer discoveries22263255
less than 10 LD from Earth25273246
inside Earth SOI8387
less than 1 LD from Moon3135
less than 1 LD from Earth3033
close-passer discoveries20172528
less than 10 LD from Earth21252241
inside Earth SOI44615
less than 1 LD from Moon1256
less than 1 LD from Earth2128
close-passer discoveries17161331
less than 10 LD from Earth19384346
inside Earth SOI19810
less than 1 LD from Moon1444
less than 1 LD from Earth1325
close-passer discoveries13282531
less than 10 LD from Earth63648995
inside Earth SOI19183125
less than 1 LD from Moon671211
less than 1 LD from Earth881211
close-passer discoveries43527377
less than 10 LD from Earth681067753
inside Earth SOI15261911
less than 1 LD from Moon5843
less than 1 LD from Earth51153
close-passer discoveries58935034
less than 10 LD from Earth707290
inside Earth SOI211528
less than 1 LD from Moon10512
less than 1 LD from Earth7616
close-passer discoveries546376
less than 10 LD from Earth426362
inside Earth SOI71410
less than 1 LD from Moon135
less than 1 LD from Earth026
close-passer discoveries214443

Neighborhood timeline index by month & year


Maximum daily counts of known objects

Within ten LD of Earth:37 on 15 Oct. 2017
Inside Earth SOI:6 on four days, most recently 5 Sept. 2018 & 19 Jan. 2018
Within one LD of the Moon:4 on 21 Sept. 2019, 26 Feb. 2019 & 20 Oct. 2017
Inside Moon SOI:1 on six days, most recently 2 Sept. 2019 & 23 March 2019
Inside Earth-Moon system:3 on four days, most recently 21 Sept. 2019 & 18 Jan. 2018

Designation Credits 2010-2019

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.

Totals2019201820172016201520142013201220112010Who & where
1330195222279220849664846323MLS - Mt. Lemmon Survey in Arizona
77762128739011010474714718CSS - Catalina Sky Survey in Arizona
5549843114788659382513-PS1 - Pan-STARRS 1 in Hawaii
1075045--111----ZTF - Zwicky Transient Facility in southern California
83352523-------ATLAS Mauna Loa in Hawaii
702028157------ATLAS Haleakala in Hawaii
49-------172012LINEAR in New Mexico
41---16520----Allen/DECam - Lori Allen
291514--------PS2 - Pan-STARRS 2 in Hawaii
16-----44251La Sagra Obs. in Spain
15--546-----SST Atom Site - Space Surveillance Telescope Atom Site in New Mexico
15------3651SSS - Siding Spring Survey in New South Wales
14123431----SONEAR in Brazil
734--------JAXA Janess-G in New South Wales
7----1-1131Spacewatch 0.9m telescope in Arizona
5--2111----WISE in Earth polar orbit
5--2--3----ESA OGS - ESA Optical Ground Station in the Canary Islands
4-31-------Xuyi Sta. - Purple Mtn. Obs. Xuyi Station in China
22---------Tokyo-Kiso Obs. in Japan
211--------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---------Campo dos Amarais Obs.
1-1--------R. Wainscoat/Mauna Kea - R. Wainscoat
1--1-------Nyukasa Obs. in Japan
1--1-------GINOP-KHK in Hungary
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
158Total in 2011 = 0.43 objects per day
209Total in 2012 = 0.57 objects per day
187Total in 2013 = 0.51 objects per day
299Total in 2014 = 0.82 objects per day
301Total in 2015 = 0.82 objects per day
422Total in 2016 = 1.15 objects per day
521Total in 2017 = 1.43 objects per day
516Total in 2018 = 1.41 objects per day
483Total in 2019 = 1.69 objects per day
3153Total designation credits for the 3282-day period = 0.96 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
20540744051CSS - 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---WISE 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
173Total in 2009 = 0.47 objects per day
120Total in 2010 = 0.41 objects per day
572Total 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 4669-day reporting period, since 1 Jan. 2007.

Totals2019201820172016201520142013201220112010200920082007Who & where
394385449403024273836508--ARO Westfield in Illinois
342-5104102532610-12120--Tenagra II Obs. in Arizona
33945613321231818241712291820Great Shefford Obs. in England
31129362815172820272225261523Spacewatch 1.8m telescope in Arizona
2699595532312-------Steward Mt. Lemmon Sta. - Steward Obs. Mt. Lemmon Station in Arizona
23513194015112011191313152620MLS - Mt. Lemmon Survey in Arizona
2158711413738282410353-Mauna Kea in Hawaii
167---35293625239253-Tholen team/Mauna Kea - David Tholen's team
1611824262629154452431Mt. John Obs. in New Zealand
1411813281919218681---PS1 - Pan-STARRS 1 in Hawaii
14018272321867246----CTIO - Cerro Tololo Inter-American Obs. in Chile
13718262321867244----Holmes/CTIO - Robert Holmes in Illinois
13655441916----11---Tholen 2.24m - UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii
113131613146148794621Schiaparelli Obs. in Italy
10161010788141091045-MRO - Magdalena Ridge Obs. in New Mexico
97----------345013ARO - Astronomical Research Obs. in Illinois
91--1049266-------Apache Point - Apache Point Obs. in New Mexico
90--1048266-------Nault/Apache Point - Kristie Nault
762117845105132---KPNO - Kitt Peak Natl. Obs. in Arizona
6221178437-1-1---Spacewatch/KPNO - Spacewatch
50101113511--11241Spacewatch 0.9m telescope in Arizona
44161315----------CSS-Kuiper - Catalina Sky Survey Kuiper Telescope in Arizona
442912678-------Cerro Paranal in Chile
426441-24422643CSS - Catalina Sky Survey in Arizona
352812661-------Micheli/Paranal - Marco Micheli
34131167231-----Micheli/Mauna Kea - Marco Micheli
34------3736825SSS - Siding Spring Survey in New South Wales
3211143211------DECam in Chile
31121-17732331-Sandlot Obs. in Kansas
259252-3121----ESA OGS - ESA Optical Ground Station in the Canary Islands
25---23191------Allen/DECam - Lori Allen
22911----1---1--ZTF - Zwicky Transient Facility in southern California
22234411--1--15KLENOT in the Czech Republic
16529----------Tholen CFHT - UH/Tholen NEO Follow-Up CFH Telescope in Hawaii
15123-----------Visnjan Obs.
1543211121-----McDonald Obs. in Texas
15-21313---5---WISE in Earth polar orbit
132241-11---2--Castelmartini Obs. in Italy
122--1-2412----St. Pardon de Conques Obs. in France
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)

1846 UT on 26 Oct. 2019-see JPL Close Approaches
0.000 days total in 2019
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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