Moon of Jupiter
Amalthea
Amalthea is a moon. It orbits Jupiter. It is about 167 km across – about as wide as Switzerland. Amalthea is one of the reddest objects in the Solar System – probably because of sulphur drifting over from Io.
Fact file
- Type
- Moon of Jupiter
- Diameter
- 167 km
- Distance from Jupiter
- 181,400 km
- Orbital period
- 0.5 days
- Temperature
- -153 °C on average
Amalthea orbits Jupiter.
Interesting facts about Amalthea
- Amalthea is one of the reddest objects in the Solar System – probably because of sulphur drifting over from Io.
- It is potato-shaped (250 x 146 x 128 km) and so porous that it is probably a loose rubble pile.
- Discovered in 1892 by Edward Barnard – the last moon to be found by eye at the telescope (without photography).
Frequently asked questions about Amalthea
How big is Amalthea?
Amalthea has a diameter of 167 km. That is about 4.8% of the diameter of our Moon.
How far is Amalthea from Jupiter?
Amalthea orbits Jupiter at an average distance of 181,400 km.
How long does Amalthea take to orbit Jupiter?
Amalthea orbits Jupiter once every 12 hours.
How cold or warm is it on Amalthea?
On Amalthea the average temperature is −153 °C.
Formation
Its low density suggests that Amalthea did not form where it is today, but further out, and was later captured or clumped together.
Atmosphere
No atmosphere. Dust knocked off Amalthea by impacts feeds one of Jupiter's faint “gossamer” rings.
Exploration
The Galileo probe flew past in 2002 at a distance of just 160 km and was thus able to work out its mass.
Compared with Earth
Amalthea orbits so close to Jupiter that one circuit takes it only 12 hours.
Other moons of Jupiter
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