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Asteroid Near-Earth

2003 WU21

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(2003 WU21)

Where is it now

Distance from Sun
1.039 AU
True anomaly
134.92°
Distance from Earth
1.006 AU
As of
21 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 — 0.995 AU from the Sun Earth 2003 WU21 — 1.039 AU from the Sun 2003 WU21
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2003 WU21 is 1.006 AU from Earth today (8.4 light-minutes).

In the sky

Right ascension
17h 39m 21s
Declination
-52° 50′ 30″
Constellation
Ara
Distance from Earth
1.01 AU
Elongation from the Sun
62.55° — 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
0.909 AU
Eccentricity
0.5449
Inclination
28.6°
Orbital period
316.6 days
Perihelion
0.414 AU
Aphelion
1.405 AU
Longitude of ascending node
57.51°
Argument of periapsis
140.7°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 27.1 LD
0.0697 AU
Tisserand (Jupiter)
6.339

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
136
Data arc
19.01 years
First observed
20 November 2003
Last observed
23 November 2022
Residual RMS
0.4 ″
Solution · Otto Matic
23 November 2022

Visual & observation

Absolute magnitude (H)
21.87

Discovery & classification

Aten Near-Earth Object

Close approaches 159 on record

Flyby geometry
Ecliptic flyby of 2003 WU21 at 2027-08-13 07:51 UTC Top-down view of the ecliptic, Earth at the centre, for the 2027-08-13 07:51 UTC close approach of 2003 WU21. Catalogue miss distance 189.3 LD · 7.28 × 10⁷ km. The curve is the geocentric path from 2027-08-10 to 2027-08-16, 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 189.3 LD · 7.28 × 10⁷ km 2027-08-13 07:51 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2027-08-13 07:51 UTC close approach of 2003 WU21. Catalogue miss distance 189.3 LD · 7.28 × 10⁷ km. The curve is the geocentric path from 2027-08-10 to 2027-08-16, 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
2027-08-13 07:51:00 Earth 0.4863 AU 189.3 LD 21.4 km/s
2029-11-26 10:19:00 Earth 0.0919 AU 35.8 LD 19.3 km/s
2034-07-01 19:32:00 Earth 0.4892 AU 190.4 LD 23.1 km/s
2035-11-14 21:14:00 Earth 0.3817 AU 148.6 LD 16.4 km/s
2036-11-16 20:33:00 Earth 0.3101 AU 120.7 LD 28.7 km/s
2040-08-14 19:45:00 Earth 0.4913 AU 191.2 LD 21.9 km/s
2042-11-26 19:00:00 Earth 0.1092 AU 42.5 LD 18.8 km/s
2047-07-05 09:31:00 Earth 0.4862 AU 189.2 LD 22.6 km/s
2048-11-12 12:17:00 Earth 0.3993 AU 155.4 LD 16.4 km/s
2049-11-18 06:58:00 Earth 0.2809 AU 109.3 LD 27.8 km/s

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

Sources