This object moves — fetching its current position…
Score breakdown
· 5 badges
41 pts · Rare
Rare50 pts → Epic
Centaur: adrift between the giants+20
Retrograde orbit+8
Notably bright (low H)+8
Kuiper-belt object+5
Catalogue designation only+0
Total score41
9 more points to reach Epic.
Badges
❄️Kuiper-belt object· +5
⏪Retrograde orbit· +8
💡Notably bright (low H)· +8
🔢Catalogue designation only
🦌Centaur: adrift between the giants· +20
✨ Trivia
Hard to believe
🔄Against the traffic. It goes round the Sun backwards, against the direction every planet and almost everything else travels.
What it actually is
🛸Its orbit family. A centaur, wandering between the orbits of Jupiter and Neptune on a path nothing can stabilise. Half asteroid and half comet, and gone from this orbit within a few million years.
🌞Closest approach. At its nearest it comes within 11.15 AU of the Sun — inside the orbit of Uranus.
🔁One lap. A single orbit around the Sun takes it about 97.6 years.
🥏How far it roams. Its orbit swings between 11.16 and 31.24 AU from the Sun.
Sense of scale
🧱Sense of scale. In everyday terms it is about 2.9× the length of Manhattan island.
🚶Walk around it. Walking its equator at a steady pace, eight hours a day, would take about 5 days.
By the numbers
📐Size. Roughly 63.7 km across.
Properties
albedo
0.083
aphelion au
31.24
designation
2011 MM4
diameter km
63.7
eccentricity
0.4738
full name
(2011 MM4)
h mag
9.51
inclination
100.34
mean motion deg day
0.0101
moid au
10.1
name
2011 MM4
number only
yes
orbit class
CEN
perihelion au
11.152
semi major au
21.2
About 2011 MM4
2011 MM4 is a rare kbo. It swings within 11.152 AU of the Sun at perihelion.
A centaur, wandering between the orbits of Jupiter and Neptune on a path nothing can stabilise. Half asteroid and half comet, and gone from this orbit within a few million years.
How to see it
Like any astronomical target, 2011 MM4 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 2011 MM4 is a rare kbo
2011 MM4 scores 41 points on Spacedle's rarity scale, which places it in the rare tier. Another 9 points would lift it into a rarer tier.
That score comes from 5 science badges — Kuiper-belt object, Retrograde orbit, Notably bright (low H), Catalogue designation only and Centaur: adrift between the giants — 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.