Screen shot from A/CC's prototype interactive sky chart viewer. Objects in white are outside ten LD at the date and time shown, green inside ten LD, yellow inside Earth's Hill Sphere (except the Sun, of course), orange inside two LD, and red inside one LD of Earth -- all from JPL SSD Horizons data.
--> See more screen shots and with animation.
Today's Traffic: Two objects are reported passing within ten lunar distances (LD)1 of our planet today, Saturday, February 4th. 2012 BD14 and newly discovered 2012 CU both depart from within ten LD today.
One object is known to be approaching to within ten LD between now and early March. 2011 CP4 will come inside ten LD on February 22nd.
Eight objects that recently flew past Earth at less than ten LD remain of continuing active interest. See their details below.
This report was refreshed at 0607 UTC. 2012 CU is new to this page after its announcement yesterday.
Note: Watch A/CC's separate "Traffic Report" in "The Tracking News" for quicker updates and direct links to the observing record for close passers.
1. Ten lunar distances: A "lunar distance" (LD) is the average distance between Earth and Moon (about 384,400 km., the same as 238,855 miles or nearly ten [9.59] times around Earth's equator). Ten lunar distances has no special astronomical importance but is a useful arbitrary "bubble" within which to organize this report. An approach by a small Solar-System body starts to become interesting at less than four LD out from Earth as it encounters our planet's "Hill sphere" (distance indicated by the blue line in this illustration at about 3.9 LD). This is a region within which Earth's gravitational influence can change the orbital paths of passing objects. The Moon also has a Hill sphere, outlined here as a gray circle. (The Earth and Moon are not shown to scale.) The "Earth-Moon system" is generally defined as that region of space within a radius of one lunar distance from Earth, so an object can pass very close to the Moon yet not be described as coming "inside" the E-M system.
2. Data credit: 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 associated with this page or A/CC, and responsibility for the interpretation of this information and its use here rests entirely with A/CC. Important note: Approach times presented here as to-the-minute may have unstated uncertainties of a few minutes, or many minutes or even hours for objects with old or very short observation spans, which is significant because the Earth moves through its own diameter in about six minutes. Thus actual encounter distances may vary, occasionally by as much as ten lunar distances. See JPL's Close Approach Tables for nominal vs. minimum possible passage distances and times and for their note about uncertainties.
3. Size estimates: Object diameters are rough approximations derived by standard formula from H, an object's "absolute magnitude" (brightness), where higher numbers represent dimmer (thus usually smaller) objects.
| 2012 BD14 - departing | |
| Approximate diameter: | 15 meters (H=26.743) |
| Closest Earth approach: | 5.79 LD at 2210 UTC on 30 Jan. |
| Inside ten LD of Earth: | 25 Jan. until today |
| Data based on: | JPL SSD orbit solution #11 downloaded 31 Jan. based on 59 observations spanning 10 days including radar observation |
| Optical observation: | observed from 7 locations during 9.7491 days first observed at 0712 UTC on 20 Jan. by the Mt. Lemmon Survey last observed at 0111 UTC on 30 Jan. by Astronomical Research Obs. Westfield |
| Radar observation: | observed once from one location observed at 0229 UTC 27 Jan. by Arecibo |
| Links: | JPL Small-Body Database NEODyS 2012BD14 Close Approaches |
| 2012 CU - departing | |
| Approximate diameter: | 24 meters (H=25.723) |
| Closest Earth approach: | 2.41 LD at 2215 UTC on 31 Jan. |
| Inside Earth's Hill sphere: | 30 Jan. until 2 Feb. |
| Inside ten LD of Earth: | 27 Jan. until today |
| Data based on: | JPL SSD orbit solution #1 downloaded yesterday based on 16 observations spanning 1 day |
| Optical observation: | observed from 4 locations during 23.462 hours first observed at 0941 UTC on 2 Feb. by LINEAR last observed at 0909 UTC yesterday by Robert Holmes via Cerro Tololo Inter-American Obs. |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012CU Close Approaches |
| 2011 CP4 - approaching | |
| Approximate diameter: | 201 meters (H=21.129) |
| Closest Earth approach: | 9.11 LD at 1401 UTC on 23 Feb. |
| Inside ten LD of Earth: | 22 to 24 Feb. |
| Data based on: | JPL SSD orbit solution #16 downloaded 2 Feb. based on 61 observations spanning 2002-2012 |
| Optical observation: | observed from 2 locations during 3.1485 days first observed at 0953 UTC on 29 Jan. by Astronomical Research Obs. Westfield last observed at 1327 UTC on 1 Feb. by UKAPP via Faulkes Telescope North |
| Note: | radar target |
| Links: |
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These objects either departed from ten LD during the last week or were reported observed.
| 2012 BA77 - departed | |
| Approximate diameter: | 23 meters (H=25.873) |
| Closest Earth approach: | 9.51 LD at 0612 UTC on 13 Jan. - Note: JPL reports an approach uncertainty of 9 minutes. |
| Inside ten LD of Earth: | 12 to 14 Jan. |
| Data based on: | JPL SSD orbit solution #2 downloaded 30 Jan. based on 9 observations spanning 5 days |
| Optical observation: | observed from 3 locations during 4.9442 days first observed at 0848 UTC on 24 Jan. by Pan-STARRS 1 last observed at 0728 UTC on 29 Jan. by Astronomical Research Obs. Westfield |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BA77 Close Approaches |
| 2012 BO11 - departed | |
| Approximate diameter: | 24 meters (H=25.767) |
| Closest Earth approach: | 3.94 LD at 1815 UTC on 13 Jan. |
| Inside ten LD of Earth: | 8 to 19 Jan. |
| Data based on: | JPL SSD orbit solution #9 downloaded yesterday based on 48 observations spanning 14 days |
| Optical observation: | observed from 6 locations during 13.8130 days first observed at 1148 UTC on 19 Jan. by the Catalina Sky Survey last observed at 0719 UTC on 2 Feb. by the Spacewatch 1.8m telescope |
| Links: | JPL Small-Body Database NEODyS 2012BO11 Close Approaches |
| 2012 BV61 - departed | |
| Approximate diameter: | 30 meters (H=25.231) |
| Closest Earth approach: | 4.90 LD at 1835 UTC on 16 Jan. - Note: JPL reports an approach uncertainty of 4 minutes. |
| Inside ten LD of Earth: | 8 to 25 Jan. |
| Data based on: | JPL SSD orbit solution #3 downloaded 2 Feb. based on 27 observations spanning 6 days |
| Optical observation: | observed from 5 locations during 5.9610 days first observed at 1000 UTC on 26 Jan. by the Catalina Sky Survey last observed at 0903 UTC on 1 Feb. by via Cerro Tololo Inter-American Obs. |
| Links: | JPL Small-Body Database NEODyS 2012BV61 Close Approaches |
| 2012 BF27 - departed | |
| Approximate diameter: | 20 meters (H=26.093) |
| Closest Earth approach: | 1.90 LD at 2157 UTC on 20 Jan. |
| Inside Earth's Hill sphere: | 19 to 22 Jan. |
| Inside ten LD of Earth: | 17 to 24 Jan. |
| Closest Moon approach: | 1.13 LD at 1736 UTC 20 Jan. |
| Data based on: | JPL SSD orbit solution #3 downloaded 30 Jan. based on 34 observations spanning 6 days |
| Optical observation: | observed from 7 locations during 6.0910 days first observed at 0805 UTC on 23 Jan. by the Catalina Sky Survey last observed at 1016 UTC on 29 Jan. by the Spacewatch 1.8m telescope |
| Links: | JPL Small-Body Database NEODyS 2012BF27 Close Approaches |
| 2012 BS1 - departed | |
| Approximate diameter: | 7 meters (H=28.366) |
| Closest Earth approach: | 3.12 LD at 2129 UTC on 23 Jan. |
| Inside Earth's Hill sphere: | 22 to 25 Jan. |
| Inside ten LD of Earth: | 19 to 28 Jan. |
| Data based on: | JPL SSD orbit solution #3 downloaded 23 Jan. based on 19 observations spanning 3 days |
| Optical observation: | observed from 3 locations during 3.1848 days first observed at 0655 UTC on 18 Jan. by the Mt. Lemmon Survey last observed at 1121 UTC on 21 Jan. by the Spacewatch 1.8m telescope |
| Links: | JPL Small-Body Database NEODyS 2012BS1 Close Approaches |
| 2012 BW13 - departed | |
| Approximate diameter: | 12 meters (H=27.221) |
| Closest Earth approach: | 1.73 LD at 0602 UTC on 26 Jan. |
| Inside Earth's Hill sphere: | 24 to 27 Jan. |
| Inside ten LD of Earth: | 22 to 29 Jan. |
| Closest Moon approach: | 2.55 LD at 0933 UTC 26 Jan. |
| Data based on: | JPL SSD orbit solution #6 downloaded 27 Jan. based on 31 observations spanning 5 days |
| Optical observation: | observed from 5 locations during 5.6869 days first observed at 0458 UTC on 19 Jan. by the Mt. Lemmon Survey last observed at 2127 UTC on 24 Jan. by Paus Obs. |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BW13 Close Approaches |
| 2012 BA102 - departed | |
| Approximate diameter: | 17 meters (H=26.451) |
| Closest Earth approach: | 2.63 LD at 1713 UTC on 26 Jan. - Note: JPL reports an approach uncertainty of 4 minutes. |
| Inside Earth's Hill sphere: | 25 to 28 Jan. |
| Inside ten LD of Earth: | 20 Jan. until 1 Feb. |
| Data based on: | JPL SSD orbit solution #2 downloaded 1 Feb. based on 15 observations spanning 1 day |
| Optical observation: | observed from 3 locations during 1.3960 days first observed at 0507 UTC on 30 Jan. by LINEAR last observed at 1437 UTC on 31 Jan. by Moriyama Obs. |
| Note: | risk |
| Links: | JPL Small-Body Database NEODyS 2012BA102 Close Approaches |
| 2012 BX34 - departed intruder | |
| Approximate diameter: | 10 meters (H=27.63) |
| Closest Earth approach: | 0.17 LD at 1524 UTC on 27 Jan. |
| Inside Earth-Moon system: | 0422 UTC on 27 Jan. until 0226 UTC on 28 Jan. |
| Inside Earth's Hill sphere: | 25 to 29 Jan. |
| Inside ten LD of Earth: | 22 Jan. until 1 Feb. |
| Closest Moon approach: | 0.76 LD at 0043 UTC 28 Jan. |
| Inside one LD of Moon: | 1734 UTC on 27 Jan. until 0755 UTC on 28 Jan. |
| Data based on: | JPL SSD orbit solution #13 downloaded 30 Jan. based on 112 observations spanning 2 days including radar observation |
| Optical observation: | observed from 14 locations during 2.1382 days first observed at 1021 UTC on 25 Jan. by the Catalina Sky Survey last observed at 1340 UTC on 27 Jan. by the Catalina Sky Survey |
| Radar observation: | observed once from 2 locations observed at 0750 UTC 27 Jan. by Goldstone DSS-14 70m antenna (transmit) with Goldstone DSS-13 34m antenna (receive) |
| Links: |
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