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Asteroid Near-Earth Potentially hazardous

2021 MJ

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(2021 MJ)

Where is it now

Distance from Sun
1 AU
True anomaly
223.45°
Distance from Earth
0.737 AU
As of
20 October 2026

Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.

Sun Earth — 0.996 AU from the Sun Earth 2021 MJ — 1 AU from the Sun 2021 MJ
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2021 MJ is 0.737 AU from Earth today (6.1 light-minutes).

In the sky

Right ascension
16h 37m 22s
Declination
-74° 50′ 27″
Constellation
Apus
Distance from Earth
0.74 AU
Elongation from the Sun
68.52° — well clear of the Sun

Favours the southern hemisphere; low or below the horizon from far north.

From your location

See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.

How do I find my coordinates?

Google Maps on a computer

  1. Right-click the spot where you'll be observing.
  2. The first line of the menu is the coordinates, e.g. 51.50722, -0.12758 — click it and they're copied.
  3. Paste them above.

Google Maps on a phone

  1. Press and hold the spot to drop a pin.
  2. The coordinates appear in the search bar (or on the pin's card) — tap to copy, then paste above.

A full Google Maps link works too, but the short maps.app.goo.gl share links don't carry coordinates — copy the numbers instead. We round to about a kilometre; that's all the sky calculation needs.

Know your what3words address? Paste it, e.g. ///filled.count.soap. This is optional — the three words are sent to what3words to convert them, and we don't store the address or the result.

Your location stays in your browser and is sent only for this calculation. Using a what3words address is optional; if you do, the three words go to what3words to be converted and we don't record them. Set a location first, then you can save an email alert for this object. See our privacy policy.

Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.

Orbital elements

Semi-major axis
0.892 AU
Eccentricity
0.1956
Inclination
40.11°
Orbital period
307.9 days
Perihelion
0.718 AU
Aphelion
1.067 AU
Longitude of ascending node
122.83°
Argument of periapsis
20.79°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 13.2 LD
0.034 AU
Tisserand (Jupiter)
6.452

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
88
Data arc
16.1 years
First observed
26 June 2010
Last observed
2 August 2026
Residual RMS
0.54 ″
Solution · Otto Matic
3 August 2026

Visual & observation

Absolute magnitude (H)
20.45

Discovery & classification

Aten Near-Earth Object Potentially Hazardous Asteroid

Close approaches 51 on record

Flyby geometry
Ecliptic flyby of 2021 MJ at 2037-07-24 06:59 UTC Top-down view of the ecliptic, Earth at the centre, for the 2037-07-24 06:59 UTC close approach of 2021 MJ. Catalogue miss distance 41.1 LD · 1.58 × 10⁷ km. The curve is the geocentric path from 2037-07-21 to 2037-07-27, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. At closest approach the object is south of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 41.1 LD · 1.58 × 10⁷ km 2037-07-24 06:59 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2037-07-24 06:59 UTC close approach of 2021 MJ. Catalogue miss distance 41.1 LD · 1.58 × 10⁷ km. The curve is the geocentric path from 2037-07-21 to 2037-07-27, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. At closest approach the object is south of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate.

JPL Horizons

When (UTC) Body Distance Lunar distances Relative speed
2031-04-10 15:39:00 Venus 0.0787 AU 30.6 LD 24.6 km/s
2037-07-24 06:59:00 Earth 0.1055 AU 41.1 LD 19.3 km/s
2047-04-13 13:24:00 Venus 0.0604 AU 23.5 LD 24 km/s
2053-07-25 09:17:00 Earth 0.0393 AU 15.3 LD 19.4 km/s
2054-01-12 15:19:00 Venus 0.1049 AU 40.8 LD 24.9 km/s
2069-07-26 09:27:00 Earth 0.0571 AU 22.2 LD 19.7 km/s
2070-01-15 02:42:00 Venus 0.0209 AU 8.1 LD 24 km/s
2076-10-17 13:01:00 Venus 0.105 AU 40.9 LD 24.9 km/s
2080-07-23 21:15:00 Earth 0.1339 AU 52.1 LD 19.3 km/s
2092-10-23 16:21:00 Venus 0.1291 AU 50.2 LD 24.3 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources