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99942 · Aten Group Apophis
Caution
Data · JPL Horizons
Updated 2026·05·26 14:21 UTC
Discovered in 2004, Apophis is an Aten-group asteroid whose 2029 close approach will bring it to 31,800 km from Earth — 0.083 lunar distances — at 7.42 km/s.
⊙ Next Close Approach
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01
Orbital Elements
Keplerian elements from JPL Horizons — epoch JD 2461000.5, heliocentric ecliptic J2000.
Semi-major (a)
0.9224 AU
Period 323.6 d
Eccentricity (e)
0.1914
Aten-type, crosses Earth's orbit
Inclination (i)
3.34°
w.r.t. ecliptic plane
Longitude (Ω)
204.45°
Ascending node
Arg. periapsis (ω)
126.42°
Orientation in plane
Mean anomaly (M)
88.36°
At epoch JD 2461000.5
Sun
Earth · 1.00 AU
Apophis · 0.9224 AU
| Year | Date | Miss · km | Miss · LD | Velocity | Body |
|---|---|---|---|---|---|
| 2004 | Dec 21 | 14,200,000 | 36.93 | 5.86 km/s | Earth |
| 2013 | Jan 09 | 14,460,000 | 37.60 | 5.84 km/s | Earth |
| 2021 | Mar 06 | 16,910,000 | 43.98 | 5.79 km/s | Earth |
| 2029 | Apr 13 | 31,800 | 0.083 | 7.42 km/s | Earth |
| 2036 | Apr 13 | 27,840,000 | 72.39 | 6.21 km/s | Earth |
| 2051 | Apr 12 | 1,930,000 | 5.02 | 9.32 km/s | Earth |
| 2066 | Apr 13 | 11,640,000 | 30.28 | 5.94 km/s | Earth |
02
JPL Accuracy
Solution quality, observation arc, and position uncertainty — pulled from JPL Horizons.
Position uncertainty (σ)
412 km
3σ along-track deviation at the close approach, propagated forward from JPL Horizons covariance matrix.
Observation arc
21.7 years
8,792 individual astrometric observations across 47 observatories.
Last updated
14h ago
JPL Horizons solution K224/56 · pulled 2026·05·26 14:21 UTC into local cache.
Condition code
0 / 9
0 = essentially deterministic. This trajectory is among the most precisely known in the catalog.
03
Jupiter Perturbation
How outer-planet gravity bends the trajectory between now and the 2068 century-of-uncertainty mark.
Δposition · 2068
247,859,193 km
Δvelocity · cumulative
59.154929 km/s
Max divergence
280,569,549 km
04
What does 31,800 km mean?
A tasteful, accurate comparison — without the clickbait. Against other known orbital references.
Low Earth OrbitISS · 408 km
408 km
Geostationary beltCommunications satellites
35,786 km
ApophisThis object's close approach
31,800 km
MoonMean orbital distance
384,400 km
Apophis will pass at 0.083 lunar distances — closer than
the geostationary belt that hosts your TV and GPS satellites.
At 7.42 km/s relative velocity, this is one of the most significant
close approaches of our generation.