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

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(2014 KH39)

Designation: 2014 KH39 · NASA id: 3672463

Estimated diameter: 15 – 34 meters

≈ the Chelyabinsk object
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 = 26.2) · JPL Small-Body Database →

Earth impact concern
No identified impact threat
Why?
  • Its closest recorded pass was 1.1 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

49 kilotonnes – 1.8 megatonnes 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 period1,310.3 days (3.59 years)
Eccentricity.5925778687445364 (0 = circular, closer to 1 = more elongated)
Semi-major axis2.343390517132995 AU
Inclination5.449609585918964° (tilt of its orbit vs. Earth's)
Perihelion distance.9547491588541677 AU (closest approach to the Sun)
Aphelion distance3.732031875411822 AU (farthest from the Sun)
Minimum Orbit Intersection Distance0.00315 AU = 471,458 km
(closest its orbit path ever comes to Earth's, regardless of timing)
Ascending node longitude74.57678567783975°
Argument of perihelion210.9938009277603°
Mean anomaly / motion64.07955187997483° / .274749601799943°/day
Jupiter Tisserand invariant3.297 (helps distinguish asteroids from comets)
Reference epoch / equinoxJD 2461000.5 / J2000
Orbit determined2021-04-15 10:04:34
Observed2014-05-24 to 2014-06-04 (11 day arc, 48 observations used)
Orbit uncertainty4 (0 = best known, 9 = least certain)

Close Approach History

Every close approach NASA has on record for this object — 27 total.

Why does it pass Earth, Juptr, 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. 16 of them were approaches to Earth, 8 of them were approaches to Juptr, 2 of them were approaches to Mars and 1 of them were approaches to Moon.

This one’s path runs from 0.955 AU at its closest to the Sun out to 3.732 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 1310.3 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 (0.0032 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: 2032-05-05

Date Passed near Velocity (km/h) Miss distance
2183-09-07 Earth 63284.83 37,443,069 km
97.4 LD
2165-09-08 Earth 66133.77 42,562,604 km
111 LD
2156-06-26 Juptr 12127.04 226,304,674 km
589 LD
2147-08-14 Earth 39171.94 12,946,123 km
33.7 LD
2136-06-22 Mars 47062.89 14,585,911 km
37.9 LD
2129-10-23 Mars 43325.92 14,802,199 km
38.5 LD
2129-09-07 Earth 65069.04 40,070,573 km
104 LD
2120-06-22 Juptr 12567.79 229,544,834 km
597 LD
2111-08-26 Earth 49941.52 23,229,107 km
60.4 LD
2093-09-10 Earth 73221.66 51,010,573 km
133 LD
2084-06-13 Juptr 15983.27 298,862,455 km
777 LD
2075-09-06 Earth 68009.77 46,503,720 km
121 LD
2073-09-30 Juptr 13865.86 271,546,228 km
706 LD
2057-09-17 Earth 87801.65 70,807,423 km
184 LD
2050-05-07 Earth 72259.10 46,562,210 km
121 LD
2037-10-02 Juptr 11972.94 222,409,103 km
579 LD
2032-05-05 next Earth 74696.99 50,746,862 km
132 LD
2014-06-03 Earth 39806.90 439,165 km
1.14 LD
2014-06-03 Moon 43027.05 588,121 km
1.53 LD
2001-10-01 Juptr 13076.37 234,802,758 km
611 LD
1996-05-04 Earth 76266.32 54,759,370 km
142 LD
1985-09-08 Earth 72954.50 50,773,311 km
132 LD
1967-09-02 Earth 61915.09 36,252,284 km
94.3 LD
1954-11-05 Juptr 12641.75 234,812,533 km
611 LD
1949-06-14 Earth 35613.49 5,511,092 km
14.3 LD
1931-07-30 Earth 36084.51 11,934,095 km
31.0 LD
1918-10-27 Juptr 12228.36 222,158,252 km
578 LD

Looked up from NASA's NeoWs API and cached — last refreshed 2026-09-05T14:38:41.962040+00:00.