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Score breakdown
· 6 badges
29 pts · Uncommon
Uncommon34 pts → Rare
Crosses Earth's orbit+8
Aten: mostly inside Earth's orbit+8
Near-Earth object+5
Tiny fragment (<1 km)+4
Stony asteroid+4
Catalogue designation only+0
Total score29
5 more points to reach Rare.
Badges
🌠Near-Earth object· +5
🤏Tiny fragment (<1 km)· +4
🎯Crosses Earth's orbit· +8
🔢Catalogue designation only
⚱️Aten: mostly inside Earth's orbit· +8
🧗Stony asteroid· +4
✨ Trivia
What makes it special
🎯It crosses our path. Its orbit genuinely intersects Earth's track around the Sun. The two paths cross; only the timing keeps them apart.
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 0.22 AU of the Sun — inside the orbit of Mercury.
🔁One lap. A single orbit around the Sun takes it about 232 days.
🥏How far it roams. Its orbit swings between 0.22 and 1.26 AU from the Sun.
Sense of scale
🧱Sense of scale. In everyday terms it is about 5.6 football pitches across.
Standing on it
🔥Sunlight there. At closest approach the Sun beats down about 20.9 times harder than it ever does on Earth.
🦘Don't jump. Escape velocity here is only around 0.36 m/s. A determined jump would launch you off it and into your own orbit around the Sun.
Properties
albedo
0.32
aphelion au
1.26
designation
85953
diameter km
0.59
eccentricity
0.7031
full name
85953 (1999 FK21)
h mag
18.09
inclination
12.6
mean motion deg day
1.552
moid au
0.0709
name
(85953) 1999 FK21
number only
yes
orbit class
ATE
perihelion au
0.219
rotation period h
28.08
semi major au
0.7389
spec taxonomy
S
spect
S
About (85953) 1999 FK21
(85953) 1999 FK21 is an uncommon neo. It has spectral type S and swings within 0.219 AU of the Sun at perihelion.
Its orbit genuinely intersects Earth's track around the Sun. The two paths cross; only the timing keeps them apart.
How to see it
Like any astronomical target, (85953) 1999 FK21 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 (85953) 1999 FK21 is an uncommon neo
(85953) 1999 FK21 scores 29 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 5 points would lift it into a rarer tier.
That score comes from 6 science badges — Near-Earth object, Tiny fragment (<1 km), Crosses Earth's orbit, Catalogue designation only, Aten: mostly inside Earth's orbit and Stony asteroid — 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.