About Io
Io is a rare moon.
It orbits about 5.2 AU from the Sun — roughly 5.2 times Earth's distance.
Rare moon 48 EP
Io
Position computed live · planets
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Live ephemeris
This object moves — fetching its current position…
Score breakdown
· 4 badgesRare 50 pts → Epic
- Volcanically active +18
- Moon +16
- Has a proper name +8
- Tidally locked +6
Total score 48
2 more points to reach Epic.
Badges
- Moon · +16
- Has a proper name · +8
- Volcanically active · +18
- Tidally locked · +6
Trivia
Hard to believe
- Round under its own weight. Big enough that its own gravity has pulled it into a sphere — most of its neighbours are potato-shaped rubble.
What it actually is
- Its address. It orbits about 5.2 AU from the Sun — roughly 5.2 times Earth's distance.
- Around its planet. It circles its planet at a distance of 421.7 thousand km — about the same as the Earth–Moon gap — coming right round once every 1.8 days.
Sense of scale
- Against Earth. It is only 29% of Earth's width — you could pack about 42.8 of it inside our planet.
- Ground to cover. Its whole surface adds up to about 41.7 million km² — about 28% of Earth's dry land.
- Walk around it. Walking right round its equator, eight hours a day, would take about 9.4 months.
Time and light
- Sunrise is late. Sunlight takes about 43.3 minutes to get there, against eight minutes to reach us.
Standing on it
- Volcanic. Its surface is constantly resurfaced by eruptions — the most volcanically active place we know of.
Properties
- color
- #e4d56a
- diameter km
- 3643.2
- name
- Io
- named
- yes
- radius km
- 1821.6
- tidally locked
- yes
- volcanic
- yes
How to see it
Like any astronomical target, Io 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 Io is a rare moon
Io scores 48 points on Spacedle's rarity scale, which places it in the rare tier. Another 2 points would lift it into a rarer tier.
That score comes from 4 science badges — Moon, Has a proper name, Volcanically active and Tidally locked — 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.