About Hydra
Hydra is an uncommon moon.
It orbits about 39.48 AU from the Sun — roughly 39.5 times Earth's distance.
Uncommon moon 24 EP
Hydra
Position computed live · planets
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Live ephemeris
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Score breakdown
· 2 badgesUncommon 34 pts → Rare
- Moon +16
- Has a proper name +8
Total score 24
10 more points to reach Rare.
Badges
- Moon · +16
- Has a proper name · +8
Trivia
What it actually is
- Its address. It orbits about 39.48 AU from the Sun — roughly 39.5 times Earth's distance.
- A lopsided orbit. Its path is distinctly off-centre: it swings between 29.66 and 49.31 AU from the Sun, so its seasons are driven as much by distance as by tilt.
- Off the beaten plane. Its orbit is tilted 17° out of the flat plane the planets share — half of every lap is spent above the others, half below.
- Around its planet. It circles its planet at a distance of 64.7 thousand km — about 17% of the Earth–Moon gap — coming right round once every 38.2 days.
Sense of scale
- Ground to cover. Its whole surface adds up to about 8107 km² — roughly 5.2 times the area of Greater London.
- Walk around it. Walking right round its equator, eight hours a day, would take about 4 days.
Time and light
- Sunrise is late. Sunlight takes about 5.5 hours to get there, against eight minutes to reach us.
Standing on it
- Sunlight there. Sunlight is about 1559 times weaker than at Earth. From out here the Sun is barely a disc at all — just the most brilliant star in the sky.
Properties
- color
- #c9c5bf
- diameter km
- 50.8
- name
- Hydra
- named
- yes
- radius km
- 25.4
- tidally locked
- no
How to see it
Like any astronomical target, Hydra 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 Hydra is an uncommon moon
Hydra scores 24 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 10 points would lift it into a rarer tier.
That score comes from 2 science badges — Moon and Has a proper name — 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.