Illustration of Earth with several asteroids passing at different distances, one flagged as potentially hazardous

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(2016 WD7)

Designation: 2016 WD7 · NASA id: 3764729

Estimated diameter: 9 – 21 meters

≈ a city bus
That comparison is of size only — what an impact would do depends on speed, angle, composition and where it arrives, none of which follows from width.
(absolute magnitude H = 27.3) · JPL Small-Body Database →

Earth impact concern
No identified impact threat
Why?
  • Its closest recorded pass was 3.3 lunar distances.
  • It is not on NASA/JPL’s Sentry list, which holds every object with a computed chance of impact above zero. Most objects are not on it.
What the four levels mean
  • No identified impact threat — not on any risk list. 98.8% of the objects here.
  • On a monitored risk list — a computed chance above zero, however small. 1.2% of the objects here.
  • Among the highest-ranked — Palermo at or above −2. Two objects worldwide qualify, both studied for decades and both centuries away.
  • Exceptional — Torino 1 or more, or Palermo at or above zero. No object anywhere currently qualifies.

These describe where an object sits in a catalogue, not how dangerous it is. The full ranked list is on the impact risk page.

Energy of motion, if it ever entered the atmosphere

3 kilotonnes – 127 kilotonnes of TNT

This is not a forecast. Nothing here says this object will arrive, and almost nothing ever does — what is actually assessed, by people with far better data than this page has, is on the impact risk page. This is simply the kinetic energy such a body would carry, worked out from its size and its usual encounter speed.

The range spans a factor of 37, and it cannot be narrowed. Nobody has weighed this object. Its diameter is inferred from how bright it is under an assumed reflectivity, which carries a fixed factor of 2.24 — and because mass goes as the cube of diameter, that alone becomes a factor of 11. Density is then assumed somewhere between 1,500 and 5,000 kg/m³, from a loose rubble pile to dense rock. Quoting a tighter figure would be invented precision.

Megatonnes do not mean what the word suggests here. Most of this energy is spent high in the atmosphere, not on the ground, and the comparison with weapons misleads badly. The Chelyabinsk body released around 440 kilotonnes in 2013 — this same calculation gives it 166 to 904 — and the damage was broken windows across a city, from the shock wave of an airburst some thirty kilometres up. No crater, and nothing that reached the ground intact.

Why is one asteroid “hazardous” when closer ones are not?

Because the flag has nothing to do with how close it came on the day. NASA marks an object a Potentially Hazardous Asteroid only if both of these are true of its orbit and its size:

  • Its orbit can bring it within 0.05 AU of Earth’s — about 7.5 million km. This is the Minimum Orbit Intersection Distance, the closest the two paths ever come, not the distance on any given pass.
  • It is big enough to matter — absolute magnitude 22.0 or brighter, which is roughly 140 metres across and up. That threshold is a planning convention, not a physical boundary: it is about the size at which an impact could do regional damage. Smaller objects are not harmless, they are simply outside this definition — the Chelyabinsk object of 2013 was around 20 metres and injured about 1,500 people with the shock wave from its airburst, without ever reaching the ground intact.

The two terms: AU — astronomical unit, the average Earth–Sun distance, 149,597,871 km. 0.05 AU is about 7.5 million km.
MOID — minimum orbit intersection distance, the closest the two orbits ever come, whatever the timing. See the glossary for NEO, PHA and H.

So a large rock passing at 39 million km today can be flagged, because on some future orbit it could come far nearer — while a pebble skimming past at 4 million km is not, because it would never reach the ground.

Three objects that all passed Earth on 30 August 2026 make the point better than any definition:

Object Size Orbit’s closest to Earth’s Missed by, that day Flagged
2013 JR28 122–272 m 5.3 M km (0.035 AU) 39.2 M km Yes — both tests pass
2012 LE11 629–1,406 m 23.3 M km (0.156 AU) 26.1 M km No — orbit never gets near enough
2007 EK 3.7–8.2 m 198,000 km (0.0013 AU) 4.2 M km No — far too small

The middle one is five times larger than the flagged one and passed closer on the day, but its path can never come within 23 million km of ours. The last one’s orbit crosses inside the Moon’s distance — nearer than any other object here — and it is still not hazardous, because at a few metres across it would burn up long before it landed.

“Potentially hazardous” is a watchlist criterion, not a prediction. None of these is on a collision course; the label means an object is worth keeping precise track of over the coming centuries.

Orbital Data

Orbit class: APO — Near-Earth asteroid orbits which cross the Earth’s orbit similar to that of 1862 Apollo
a (semi-major axis) > 1.0 AU; q (perihelion) < 1.017 AU

Orbital period508.9 days (1.39 years)
Eccentricity.2060992274614799 (0 = circular, closer to 1 = more elongated)
Semi-major axis1.247442709939933 AU
Inclination.6650621056348403° (tilt of its orbit vs. Earth's)
Perihelion distance.9903457311188583 AU (closest approach to the Sun)
Aphelion distance1.504539688761009 AU (farthest from the Sun)
Minimum Orbit Intersection Distance0.00981 AU = 1,467,009 km
(closest its orbit path ever comes to Earth's, regardless of timing)
Ascending node longitude41.72940637682611°
Argument of perihelion44.75049471206145°
Mean anomaly / motion145.2368611576626° / .7074132009697935°/day
Jupiter Tisserand invariant5.129 (helps distinguish asteroids from comets)
Reference epoch / equinoxJD 2461000.5 / J2000
Orbit determined2021-04-15 18:15:11
Observed2016-11-24 to 2017-01-01 (38 day arc, 71 observations used)
Orbit uncertainty4 (0 = best known, 9 = least certain)

Close Approach History

Every close approach NASA has on record for this object — 70 total.

Why does it pass Earth, Mars and Moon? Doesn’t it orbit just one?

It orbits the Sun. Not Earth, and not Venus. The column above does not say what the asteroid goes around — it says which planet a given close approach was to. 63 of them were approaches to Earth, 6 of them were approaches to Mars and 1 of them were approaches to Moon.

This one’s path runs from 0.990 AU at its closest to the Sun out to 1.505 AU at its farthest. For scale, Venus orbits at about 0.72 AU and Earth at 1.00 AU — so an orbit spanning that range crosses the path of every planet in between, once on the way out and once on the way back.

Crossing a planet’s path is not the same as meeting the planet. Almost every time the asteroid crosses, that planet is somewhere else along its own orbit. A close approach is logged only on the rare occasions when both happen to arrive at the crossing point at roughly the same time — which is why the dates below are scattered rather than regular. This object takes 508.9 days to go round, against Earth’s 365.25, so the two drift in and out of step over years rather than repeating on a neat cycle.

The Minimum Orbit Intersection Distance in the table above (0.0098 AU) is the closest the two paths ever come. The miss distances below are how far apart the two bodies actually were on the day, which is almost always very much larger.

next approach: 2027-07-09

Date Passed near Velocity (km/h) Miss distance
2076-10-27 Earth 43987.13 45,766,549 km
119 LD
2073-07-03 Earth 27139.10 71,717,077 km
187 LD
2069-11-21 Earth 14183.12 6,274,108 km
16.3 LD
2066-06-21 Earth 27878.67 73,893,700 km
192 LD
2062-12-17 Earth 9821.98 1,492,740 km
3.88 LD
2062-12-17 Moon 6017.15 1,284,494 km
3.34 LD
2059-06-13 Earth 27796.84 73,514,280 km
191 LD
2056-01-21 Earth 19783.62 13,255,483 km
34.5 LD
2052-06-01 Earth 27271.25 71,866,629 km
187 LD
2049-02-04 Earth 41563.49 42,415,007 km
110 LD
2048-09-07 Earth 14805.50 44,383,784 km
115 LD
2045-05-17 Earth 25901.49 68,055,816 km
177 LD
2042-02-15 Earth 64058.39 73,640,325 km
192 LD
2041-08-14 Earth 20839.74 56,892,263 km
148 LD
2038-04-30 Earth 23201.74 61,286,274 km
159 LD
2037-05-23 Mars 14279.59 5,612,298 km
14.6 LD
2034-07-25 Earth 24477.52 65,339,808 km
170 LD
2031-04-08 Earth 18382.75 50,683,211 km
132 LD
2030-10-22 Earth 51648.16 56,373,180 km
147 LD
2027-07-09 next Earth 26618.58 70,563,636 km
184 LD
2024-03-05 Earth 8996.11 34,545,372 km
89.9 LD
2023-11-04 Earth 28704.91 24,752,827 km
64.4 LD
2020-06-24 Earth 27596.69 73,010,444 km
190 LD
2016-12-06 Earth 10122.05 1,606,819 km
4.18 LD
2013-06-21 Earth 28012.81 74,776,848 km
195 LD
2010-02-17 Earth 4162.63 30,602,013 km
79.6 LD
2009-11-06 Earth 24551.23 19,138,927 km
49.8 LD
2006-07-03 Earth 27506.84 73,509,405 km
191 LD
2003-03-29 Earth 16609.90 47,525,647 km
124 LD
2002-10-24 Earth 45639.22 47,911,409 km
125 LD
1999-07-18 Earth 25966.04 69,590,565 km
181 LD
1996-04-19 Earth 22133.97 59,272,043 km
154 LD
1992-08-03 Earth 23161.05 62,746,261 km
163 LD
1989-05-07 Earth 25422.33 67,334,335 km
175 LD
1986-02-08 Earth 54001.74 59,536,492 km
155 LD
1985-08-24 Earth 18502.51 52,445,576 km
136 LD
1982-05-23 Earth 27300.04 72,332,085 km
188 LD
1979-01-27 Earth 31928.77 29,249,110 km
76.1 LD
1978-09-23 Earth 10115.02 37,480,843 km
97.5 LD
1975-06-06 Earth 28079.04 74,591,169 km
194 LD
1972-01-06 Earth 12395.05 4,524,166 km
11.8 LD
1968-06-06 Earth 27685.27 73,299,755 km
191 LD
1965-12-09 Mars 15636.30 3,700,349 km
9.63 LD
1965-01-21 Earth 24419.08 19,381,866 km
50.4 LD
1961-05-28 Earth 27183.77 71,812,333 km
187 LD
1959-12-30 Mars 18334.51 5,572,407 km
14.5 LD
1958-02-01 Earth 41856.05 42,778,599 km
111 LD
1957-09-04 Earth 14782.57 44,624,879 km
116 LD
1954-05-15 Earth 26004.99 68,517,324 km
178 LD
1951-02-11 Earth 61592.68 70,097,890 km
182 LD
1950-08-14 Earth 20384.16 55,767,597 km
145 LD
1947-04-30 Earth 23823.69 62,907,850 km
164 LD
1943-07-27 Earth 23836.91 63,737,862 km
166 LD
1940-04-12 Earth 20309.60 54,607,311 km
142 LD
1939-10-16 Earth 58867.23 66,602,767 km
173 LD
1936-07-12 Earth 25988.71 69,075,304 km
180 LD
1933-03-21 Earth 14515.28 43,096,817 km
112 LD
1932-10-25 Earth 39505.27 39,538,049 km
103 LD
1929-06-29 Earth 27200.34 72,146,827 km
188 LD
1925-11-07 Earth 21565.64 15,256,722 km
39.7 LD
1922-06-20 Earth 27759.13 73,546,352 km
191 LD
1918-11-24 Earth 11548.57 2,969,057 km
7.72 LD
1916-09-21 Mars 18204.37 3,354,482 km
8.73 LD
1912-03-23 Earth 16076.82 46,671,111 km
121 LD
1911-10-22 Earth 43957.17 45,456,828 km
118 LD
1911-01-27 Mars 19723.62 6,695,878 km
17.4 LD
1908-07-16 Earth 25804.01 69,470,583 km
181 LD
1905-06-04 Mars 21397.49 10,479,408 km
27.3 LD
1905-04-24 Earth 23499.47 62,738,979 km
163 LD
1901-08-10 Earth 21292.27 58,540,148 km
152 LD

Looked up from NASA's NeoWs API and cached — last refreshed 2026-09-05T00:44:55.983389+00:00.