This object moves — fetching its current position…
Score breakdown
· 5 badges
35 pts · Rare
Rare50 pts → Epic
Potentially hazardous+12
Darker than charcoal+10
Aten: mostly inside Earth's orbit+8
Near-Earth object+5
Catalogue designation only+0
Total score35
15 more points to reach Epic.
Badges
🌠Near-Earth object· +5
⚠️Potentially hazardous· +12
🔢Catalogue designation only
⚱️Aten: mostly inside Earth's orbit· +8
🕶️Darker than charcoal· +10
✨ Trivia
Handle with care
🛡️What 'hazardous' means. 'Potentially hazardous' is bookkeeping, not a prediction: it means the orbit passes within 0.05 AU of Earth's and the body is big enough to matter. Nothing on that list is known to be on a collision course.
☄️If it ever hit. A rock this size arriving at a typical 20 km/s would release around 429.6 thousand megatons — enough to devastate a region the size of a small country.
What it actually is
🛸Its orbit family. An Aten-class object, spending most of its time inside Earth's orbit and crossing ours from the sunward side — which makes this family wretchedly hard to spot against the daylight.
🌞Closest approach. At its nearest it comes within 0.52 AU of the Sun — inside the orbit of Venus.
🔁One lap. A single orbit around the Sun takes it about 252 days.
🥏How far it roams. Its orbit swings between 0.52 and 1.04 AU from the Sun.
Sense of scale
🧱Sense of scale. In everyday terms it is roughly 0.2× the height of Mount Everest.
Standing on it
🦘Don't jump. Escape velocity here is only around 1.13 m/s. A determined jump would launch you off it and into your own orbit around the Sun.
Properties
albedo
0.029
aphelion au
1.04
designation
363505
diameter km
1.876
eccentricity
0.3369
full name
363505 (2003 UC20)
h mag
18.48
inclination
3.78
mean motion deg day
1.427
moid au
0.0353
name
(363505) 2003 UC20
number only
yes
orbit class
ATE
perihelion au
0.518
pha
yes
rotation period h
29.6
semi major au
0.7813
About (363505) 2003 UC20
(363505) 2003 UC20 is a rare neo. It swings within 0.518 AU of the Sun at perihelion.
An Aten-class object, spending most of its time inside Earth's orbit and crossing ours from the sunward side — which makes this family wretchedly hard to spot against the daylight.
How to see it
Like any astronomical target, (363505) 2003 UC20 is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. Because it moves against the background stars, the live position panel on this page tracks where it is right now. The visibility panel above works out tonight's viewing window for your saved location.
Why (363505) 2003 UC20 is a rare neo
(363505) 2003 UC20 scores 35 points on Spacedle's rarity scale, which places it in the rare tier. Another 15 points would lift it into a rarer tier.
That score comes from 5 science badges — Near-Earth object, Potentially hazardous, Catalogue designation only, Aten: mostly inside Earth's orbit and Darker than charcoal — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.