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

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16960 (1998 QS52)

Designation: 16960 · NASA id: 2016960 · Potentially Hazardous

Estimated diameter: 3,635 – 8,129 meters

≈ more than a kilometre across
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 = 14.32) · JPL Small-Body Database →

Earth impact concern
No identified impact threat
Why?
  • Its closest recorded pass was 3.2 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

3,915,165 megatonnes – 145,909,576 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 period1,192.3 days (3.26 years)
Eccentricity.8591108377047543 (0 = circular, closer to 1 = more elongated)
Semi-major axis2.200560760989583 AU
Inclination17.51488517740576° (tilt of its orbit vs. Earth's)
Perihelion distance.3100351621956108 AU (closest approach to the Sun)
Aphelion distance4.091086359783555 AU (farthest from the Sun)
Minimum Orbit Intersection Distance0.01808 AU = 2,704,580 km
(closest its orbit path ever comes to Earth's, regardless of timing)
Ascending node longitude260.1352737400699°
Argument of perihelion243.2687579621906°
Mean anomaly / motion129.8231838118127° / .3019284426777465°/day
Jupiter Tisserand invariant2.999 (helps distinguish asteroids from comets)
Reference epoch / equinoxJD 2461200.5 / J2000
Orbit determined2026-08-23 06:49:14
Observed1983-06-14 to 2026-08-20 (15773 day arc, 3519 observations used)
Orbit uncertainty0 (0 = best known, 9 = least certain)

Close Approach History

Every close approach NASA has on record for this object — 31 total.

Why does it pass Juptr, Venus, Earth and Merc? 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. 10 of them were approaches to Juptr, 9 of them were approaches to Venus, 8 of them were approaches to Earth and 4 of them were approaches to Merc.

This one’s path runs from 0.310 AU at its closest to the Sun out to 4.091 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 1192.3 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 (0.0181 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: 2033-04-18

Date Passed near Velocity (km/h) Miss distance
2199-06-29 Juptr 36659.54 270,461,658 km
704 LD
2195-01-22 Merc 119121.50 9,037,400 km
23.5 LD
2185-04-15 Venus 125768.65 1,235,929 km
3.22 LD
2163-11-01 Juptr 30058.71 242,675,332 km
631 LD
2162-06-20 Earth 122690.33 20,345,016 km
52.9 LD
2149-06-09 Earth 99011.04 20,965,683 km
54.5 LD
2149-04-03 Venus 132197.66 18,158,428 km
47.2 LD
2142-11-08 Venus 146358.16 19,155,903 km
49.8 LD
2129-10-12 Merc 93288.83 14,648,599 km
38.1 LD
2128-04-01 Juptr 29283.42 245,622,309 km
639 LD
2110-03-24 Venus 113553.45 10,647,552 km
27.7 LD
2106-10-26 Venus 119400.93 19,206,240 km
50.0 LD
2100-06-20 Earth 122871.56 18,631,040 km
48.5 LD
2093-10-27 Merc 121620.86 12,575,141 km
32.7 LD
2092-08-08 Juptr 33826.19 277,147,340 km
721 LD
2087-06-05 Earth 91616.40 29,352,770 km
76.4 LD
2068-12-11 Juptr 34674.39 255,519,342 km
665 LD
2067-10-10 Venus 106074.49 18,269,364 km
47.5 LD
2038-06-10 Earth 103336.48 12,153,575 km
31.6 LD
2033-04-18 next Juptr 29602.50 239,066,523 km
622 LD
2025-05-02 Venus 119280.52 9,375,855 km
24.4 LD
1997-09-16 Juptr 30231.94 256,105,884 km
666 LD
1989-06-12 Earth 106359.14 6,251,750 km
16.3 LD
1974-02-02 Juptr 39161.63 274,591,594 km
714 LD
1973-01-14 Venus 114161.56 14,478,792 km
37.7 LD
1966-06-01 Merc 120430.00 11,698,903 km
30.4 LD
1953-06-18 Earth 120470.32 14,709,514 km
38.3 LD
1938-05-20 Juptr 31192.31 238,775,487 km
621 LD
1910-12-04 Venus 142313.43 21,622,660 km
56.3 LD
1904-06-10 Earth 103296.92 11,831,291 km
30.8 LD
1902-10-08 Juptr 29447.72 248,012,803 km
645 LD

Looked up from NASA's NeoWs API and cached — last refreshed 2026-09-04T09:53:01.386179+00:00.