Asteroid (2021 JA4)
Closest pass on 2026-Nov-03 21:00 TDB (Julian Date: 2461348.374894072)
Key Facts
- On 2026-Nov-03 21:00, asteroid (2021 JA4) passed Earth at a nominal distance of 8,650,000 km (22.5 lunar distances).
- At closest approach, the object was traveling at 14.3 km/s relative to Earth.
- The object has an estimated size of 122 m, which is just over 10 school buses.
- The miss distance was about 22 times the distance to the Moon.
- Hazard classification: 50 to 140 meters. Reaches Earth surface to carve a crater over a kilometer wide (like Meteor Crater, Arizona), destroying infrastructure across an entire metropolitan region and generating damaging regional seismic waves.
Visual Scale Comparison
| Target | 122 m |
|---|---|
| Smaller | football pitch: 105 m |
| Larger | Great Pyramid: 138 m |
Object size compared to known reference benchmarks.
Miss Distance Orbital Dial
Concentric orbital rings showing Earth, Moon orbit, and asteroid trajectory.
Astrometric & Orbital Parameters
| Designation | 2021 JA4 |
|---|---|
| Full Object Name | (2021 JA4) |
| Nominal Miss Distance | 8,650,000 km (22.5 lunar distances / 0.0578117087442765 au) |
| 3-Sigma Minimum Distance | 8,648,409.63 km (22.498 LD) |
| Relative Velocity (v_rel) | 14.3272152194655 km/s (about 2 ISS orbital speeds) |
| Velocity at Infinity (v_inf) | 14.3239979789434 km/s |
| Time Uncertainty (3-sigma) | < 00:01 |
| Absolute Magnitude (H) | 22.32 mag |
| Orbit Solution ID | 5 (NASA JPL Small-Body Database) |
| Inside Moon Orbit | No |
| Inside Geostationary Ring | No |
Cite this page
Permanent URL: https://whatnearlyhitus.com/approaches/2026-Nov-03/2021-ja4/ | Machine-readable twin: index.json
APA:
What Nearly Hit Us Project. (2026). Asteroid (2021 JA4) Close Approach on 2026-Nov-03 21:00. What Nearly Hit Us. Retrieved from https://whatnearlyhitus.com/approaches/2026-Nov-03/2021-ja4/MLA:
"Asteroid (2021 JA4) Close Approach on 2026-Nov-03 21:00." What Nearly Hit Us, What Nearly Hit Us Project, 2026-09-24, https://whatnearlyhitus.com/approaches/2026-Nov-03/2021-ja4/.BibTeX:
@misc{approach_2021JA4_202603,
title = {Asteroid (2021 JA4) Close Approach on 2026-Nov-03 21:00},
author = {{What Nearly Hit Us Project}},
year = {2026},
url = {https://whatnearlyhitus.com/approaches/2026-Nov-03/2021-ja4/},
note = {Primary upstream source: NASA/JPL CNEOS CAD API}
}