Traffic Timeline & Statistics
Refreshed at 2120 UT on 23 September 2017
[ Jump to the CURRENT timeline ]
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.
Three-Year Chart of Close-Passing Object Monthly Counts
See vertical table below left for counts & click to see
complete chart 2007-present
|less than 10 LD from Earth||29||36||47||39|
|inside Earth SOI||7||10||6||12|
|less than 1 LD from Moon||6||2||3||3|
|less than 1 LD from Earth||5||3||4||3|
|less than 10 LD from Earth||27||40||66||60|
|inside Earth SOI||6||8||17||14|
|less than 1 LD from Moon||0||2||5||3|
|less than 1 LD from Earth||1||3||7||3|
|less than 10 LD from Earth||36||42||64||84|
|inside Earth SOI||9||10||24||17|
|less than 1 LD from Moon||5||1||11||3|
|less than 1 LD from Earth||5||4||10||9|
|less than 10 LD from Earth||54||38||57||57|
|inside Earth SOI||12||10||13||11|
|less than 1 LD from Moon||0||4||3||4|
|less than 1 LD from Earth||1||4||5||6|
|less than 10 LD from Earth||51||23||32||34|
|inside Earth SOI||14||8||5||7|
|less than 1 LD from Moon||2||1||1||4|
|less than 1 LD from Earth||5||2||1||3|
|less than 10 LD from Earth||26||21||25||27|
|inside Earth SOI||4||3||8||3|
|less than 1 LD from Moon||3||0||2||0|
|less than 1 LD from Earth||3||1||3||0|
|less than 10 LD from Earth||11||11||21||25|
|inside Earth SOI||3||3||4||4|
|less than 1 LD from Moon||0||1||0||1|
|less than 1 LD from Earth||2||0||2||1|
|less than 10 LD from Earth||17||20||19||34|
|inside Earth SOI||2||3||1||8|
|less than 1 LD from Moon||1||0||0||3|
|less than 1 LD from Earth||1||1||1||2|
|less than 10 LD from Earth||40||23||63||31|
|inside Earth SOI||12||5||19||8|
|less than 1 LD from Moon||3||1||5||2|
|less than 1 LD from Earth||3||1||8||4|
|less than 10 LD from Earth||44||28||68||4|
|inside Earth SOI||5||7||15||1|
|less than 1 LD from Moon||2||2||4||1|
|less than 1 LD from Earth||3||2||5||1|
|less than 10 LD from Earth||27||48||70|
|inside Earth SOI||5||9||21|
|less than 1 LD from Moon||2||5||9|
|less than 1 LD from Earth||2||4||7|
|less than 10 LD from Earth||31||56||42|
|inside Earth SOI||8||11||7|
|less than 1 LD from Moon||1||3||0|
|less than 1 LD from Earth||2||2||0|
Neighborhood timeline index by month & year
Maximum daily counts of known objects
Designation Credits 2010-2017
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.
|Totals||2017||2016||2015||2014||2013||2012||2011||2010||Who & where|
|770||140||219||84||96||63||83||63||22||MLS - Mt. Lemmon Survey in Arizona|
|544||33||90||109||104||72||71||47||18||CSS - Catalina Sky Survey in Arizona|
|381||83||78||85||59||38||25||13||-||PS1 - Pan-STARRS 1 in Hawaii|
|49||-||-||-||-||-||17||20||12||LINEAR in New Mexico|
|40||-||16||5||19||-||-||-||-||Allen/DECam - Lori Allen|
|18||11||7||-||-||-||-||-||-||ATLAS Haleakala in Hawaii|
|16||-||-||-||4||4||2||5||1||La Sagra Obs. in Spain|
|15||5||4||6||-||-||-||-||-||SST Atom Site - Space Surveillance Telescope Atom Site in New Mexico|
|15||-||-||-||-||3||6||5||1||SSS - Siding Spring Survey in New South Wales|
|12||-||-||1||11||-||-||-||-||PTF - Palomar Transient Factory in southern California|
|11||11||-||-||-||-||-||-||-||ATLAS Mauna Loa in Hawaii|
|11||3||4||3||1||-||-||-||-||SONEAR in Brazil|
|7||-||-||1||-||1||1||3||1||Spacewatch 0.9m telescope in Arizona|
|5||2||-||-||3||-||-||-||-||ESA OGS - ESA Optical Ground Station in the Canary Islands|
|3||-||1||1||1||-||-||-||-||WISE in Earth polar orbit|
|2||1||1||-||-||-||-||-||-||Steward Mt. Lemmon Sta. - Steward Obs. Mt. Lemmon Station in Arizona|
|2||1||-||-||-||1||-||-||-||Micheli/Mauna Kea - Marco Micheli|
|2||-||-||-||-||-||1||1||-||Spacewatch 1.8m telescope in Arizona|
|1||1||-||-||-||-||-||-||-||Xuyi Sta. - Purple Mtn. Obs. Xuyi Station in China|
|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|
|55||Total in 2010 = 0.74 objects per day|
|158||Total in 2011 = 0.43 objects per day|
|208||Total in 2012 = 0.57 objects per day|
|184||Total in 2013 = 0.50 objects per day|
|298||Total in 2014 = 0.82 objects per day|
|299||Total in 2015 = 0.82 objects per day|
|421||Total in 2016 = 1.15 objects per day|
|293||Total in 2017 = 1.10 objects per day|
|1916||Total designation credits for the 2532-day period = 0.76 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.
|Totals||2010||2009||2008||2007||Who & where|
|205||40||74||40||51||CSS - Catalina Sky Survey in Arizona|
|195||50||51||58||36||MLS - Mt. Lemmon Survey in Arizona|
|103||21||23||32||27||LINEAR in New Mexico|
|32||2||13||8||9||SSS - Siding Spring Survey in New South Wales|
|23||4||7||8||4||Spacewatch 0.9m telescope in Arizona|
|3||1||1||1||-||Spacewatch 1.8m telescope in Arizona|
|2||1||1||-||-||La Sagra Obs. in Spain|
|2||-||-||1||1||LONEOS in Arizona|
|1||1||-||-||-||WISE in Earth polar orbit|
|1||-||1||-||-||Wildberg Obs. in Germany|
|1||-||1||-||-||Taunus Obs. in Germany|
|1||-||1||-||-||Hibiscus Obs. in Tahiti|
|128||Total in 2007 = 0.35 objects per day|
|148||Total in 2008 = 0.40 objects per day|
|173||Total in 2009 = 0.47 objects per day|
|120||Total in 2010 = 0.41 objects per day|
|569||Total 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 3919-day reporting period, since 1 Jan. 2007.
|Totals||2017||2016||2015||2014||2013||2012||2011||2010||2009||2008||2007||Who & where|
|283||30||39||28||24||27||39||37||51||8||-||-||ARO Westfield in Illinois|
|277||45||104||53||25||9||-||1||20||20||-||-||Tenagra II Obs. in Arizona|
|236||18||14||18||31||20||28||22||25||24||13||23||Spacewatch 1.8m telescope in Arizona|
|224||25||21||23||18||18||23||17||12||29||18||20||Great Shefford Obs. in England|
|209||9||46||38||41||29||25||10||3||5||3||-||Mauna Kea in Hawaii|
|182||20||16||9||20||12||18||13||13||15||26||20||MLS - Mt. Lemmon Survey in Arizona|
|175||-||40||30||36||26||24||9||2||5||3||-||Tholen team/Mauna Kea - David Tholen's team|
|116||23||26||29||15||4||4||5||2||4||3||1||Mt. John Obs. in New Zealand|
|95||-||-||-||-||-||-||-||-||34||48||13||ARO - Astronomical Research Obs. in Illinois|
|93||10||50||27||6||-||-||-||-||-||-||-||Apache Point - Apache Point Obs. in New Mexico|
|92||10||49||27||6||-||-||-||-||-||-||-||Nault/Apache Point - Kristie Nault|
|87||15||23||8||6||6||23||6||-||-||-||-||CTIO - Cerro Tololo Inter-American Obs. in Chile|
|85||15||23||8||6||6||23||4||-||-||-||-||Holmes/CTIO - Robert Holmes in Illinois|
|83||10||14||6||14||9||7||10||4||6||2||1||Schiaparelli Obs. in Italy|
|82||5||7||9||8||15||10||9||10||4||5||-||MRO - Magdalena Ridge Obs. in New Mexico|
|57||28||24||2||3||-||-||-||-||-||-||-||Steward Mt. Lemmon Sta. - Steward Obs. Mt. Lemmon Station in Arizona|
|56||14||10||11||12||2||2||5||-||-||-||-||PS1 - Pan-STARRS 1 in Hawaii|
|34||-||-||-||-||3||7||3||6||8||2||5||SSS - Siding Spring Survey in New South Wales|
|33||18||14||-||-||-||-||1||-||-||-||-||Tholen 2.24m - UH/Tholen NEO Follow-Up 2.24m Telescope in Hawaii|
|31||9||6||7||5||3||1||-||-||-||-||-||Micheli/Mauna Kea - Marco Micheli|
|29||2||4||5||8||5||1||3||1||-||-||-||KPNO - Kitt Peak Natl. Obs. in Arizona|
|28||-||1||-||2||4||4||2||2||6||4||3||CSS - Catalina Sky Survey in Arizona|
|27||10||5||1||1||-||1||1||1||2||4||1||Spacewatch 0.9m telescope in Arizona|
|27||-||-||1||7||7||3||2||3||3||1||-||Sandlot Obs. in Kansas|
|26||-||2||3||21||-||-||-||-||-||-||-||Allen/DECam - Lori Allen|
|26||-||2||3||21||-||-||-||-||-||-||-||DECam in Chile|
|25||4||6||7||8||-||-||-||-||-||-||-||Cerro Paranal in Chile|
|17||4||6||6||1||-||-||-||-||-||-||-||Micheli/Paranal - Marco Micheli|
|16||2||4||3||5||-||1||-||1||-||-||-||Spacewatch/KPNO - Spacewatch|
|14||4||2||-||3||2||2||1||-||-||-||-||ESA OGS - ESA Optical Ground Station in the Canary Islands|
|14||1||4||1||1||-||-||1||-||-||1||5||KLENOT in the Czech Republic|
Periods of apparent null activity
When no objects known to be within 10 LD of Earth (italics = future)
Notes about these pages:
- 2014 July 6: Went public with an improved EBN timeline home page that better handles growing data tables and also implements a separate table tallying the asteroid designation credits that replaced the formal discovery credits that stopped being noted in discovery MPECs in October 2010.
- 2014 June 29: Began noting any previous close passes since 2007 in the Object Details section of A/CC home page ("Earth's Busy Neighborhood").
- 2014 June 20: Finished general updating of timeline pages to report and count Earth SOI boundary crossings.
- 2014 June 2: Noticed and fixed a major error in presenting JPL Earth-passage uncertainties in the monthly timeline pages for a few dozen objects that have made more than one pass at less than ten LD since 2007. Also began uploading recompiled versions of these pages after revising our database and program scripts to more completely and easily count and present objects that have made multiple close passes since this reporting began in 2007.
- 2014 May 28: First opportunity to reference Earth's SOI in A/CC's EBN daily traffic report.
- 2014 May 24: Implemented methods for correctly handling impactors (two so far for Earth, none yet for the Moon) without manual intervention.
- 2014 May 19: Began switch to reporting counts of objects within Earth's gravitational sphere of influence (SOI) instead of the Hill sphere, beginning with counts only valid from May 2014 forward. The changeover was completed three days later and by June 20th SOI transits had been calculated and counts updated back through 2007.
- 2012 Feb. 22: Replaced the old static-image sky chart with a new animated sky chart and discontinued the home page "Traffic Report."
- 2012 Jan. 13: Began running a parallel "Traffic Report" generated from a new narrator script, posted to the daily Tracking News, where it now can remain part of the permanent record.
- 2011 Jan. 15: Added discovery MPEC issuance to the events timeline beginning with the last two close passers discovered in December: 2011 YB63 and YC63.
- 2011 Nov. 7: A/CC EBN traffic reporting resumed with no gaps in the Timeline.
- 2011 Aug. 9: Earth's Busy Neighborhood (EBN) traffic reporting came to a screeching halt when our data-querying scripts stopped working following changes in JPL's Horizons telnet interface.
- 2010 Nov. 1: Implemented extensive script changes to allow reporting optical observations published in MPECs while JPL's public orbit solution is locked down and not being updated for an object during a radar campaign or other circumstances.
- 2010 Oct. 19: Began implementing changes to adapt to the Minor Planet Center's new discovery credit policy.
- 2010 April 25: Finally isolated and fixed a problem in correlating uncertainty information from JPL's close approach pages for objects with multiple Earth passages of less than 10 LD since our reporting began (2007).
- 2010 April 23: Just in time for the return arrival within 10 LD of 2009 BD, many scripts were modified to properly handle objects which since 2007 have had multiple Earth passages or periods of observation outside 10 LD. (Only implemented so far for 2009 BD, more to come).
- 2009 Dec. 27: Timeline charts have been reworked to handle more than three years of data, with a truncated current chart and a new separate page with full chart.
- 2009 June 10: The May 17th changes introduced a major bug that was not understood and fixed until today, after ongoing problems were noted in processing updated JPL orbit solutions and with flagging radar targets.
- 2009 May 17: Pages updated for first time since yesterday morning after major revisions in multiple scripts to better handle multi-apparitional asteroids. (There is more work left and it's likely there will be some hiccups in how these pages work.)
- 2008 Sept. 21: Fixed a problem in characterizing an object's direction (in/outbound) at the time of a particular observation.
- 2008 June 17-19: Added data and statistics for January through September 2007.
- 2008 June 16: The EBN Timeline & Statistics page goes to a new multipage format to carry many more details and allow faster page loading.
- 2008 May 10: Object counts here rose with the addition of seven close-passing asteroids, including one briefly observed intruder (2007 VF189), that hadn't been picked up in early EBN reporting during October-November 2007. They were noticed now by a new diagnostic tool that will help avoid missing any more.
- 2008 March 24: The Timeline page was first posted.
- 2008 Jan. 2: Added sky charts to the EBN Traffic Report.
- 2007 Nov. 14: Inaugurated the semi-automated Traffic Report for Earth's Busy Neighborhood.
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