This object moves — fetching its current position…
Score breakdown
· 5 badges
49 pts · Rare
Rare50 pts → Epic
Spinning past the rubble-pile limit+22
Passes within two lunar distances of Earth's orbit+18
Near-Earth object+5
Apollo: crosses Earth's orbit+4
Catalogue designation only+0
Total score49
1 more point to reach Epic.
Badges
🌠Near-Earth object· +5
🔢Catalogue designation only
🏛️Apollo: crosses Earth's orbit· +4
⏰Spinning past the rubble-pile limit· +22
🪡Passes within two lunar distances of Earth's orbit· +18
✨ 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 278 megatons — about 5.6 times the largest bomb ever detonated.
What it actually is
🛸Its orbit family. An Apollo-class object: its orbit is wider than Earth's but crosses it. Most known Earth-crossers belong to this family.
🌞Closest approach. At its nearest it comes within 0.9 AU of the Sun — inside the orbit of Earth.
🔁One lap. A single orbit around the Sun takes it about 1.5 years.
🥏How far it roams. Its orbit swings between 0.9 and 1.68 AU from the Sun.
Sense of scale
🧱Sense of scale. In everyday terms it is about 1.5 football pitches across.
Standing on it
🦘Don't jump. Escape velocity here is only around 0.1 m/s. A determined jump would launch you off it and into your own orbit around the Sun.
Properties
aphelion au
1.68
designation
471240
eccentricity
0.3024
full name
471240 (2011 BT15)
h mag
21.7
inclination
1.66
mean motion deg day
0.6704
moid au
0.0005
name
(471240) 2011 BT15
number only
yes
orbit class
APO
perihelion au
0.902
pha
yes
rotation period h
0.1091
semi major au
1.293
About (471240) 2011 BT15
(471240) 2011 BT15 is a rare neo. It swings within 0.902 AU of the Sun at perihelion.
An Apollo-class object: its orbit is wider than Earth's but crosses it. Most known Earth-crossers belong to this family.
How to see it
Like any astronomical target, (471240) 2011 BT15 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 (471240) 2011 BT15 is a rare neo
(471240) 2011 BT15 scores 49 points on Spacedle's rarity scale, which places it in the rare tier. Another 1 point would lift it into a rarer tier.
That score comes from 5 science badges — Near-Earth object, Catalogue designation only, Apollo: crosses Earth's orbit, Spinning past the rubble-pile limit and Passes within two lunar distances of Earth's orbit — 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.