Moon of Saturn
Janus
Janus is a moon. It orbits Saturn. It is about 179 km across – about as wide as Switzerland. Janus shares its orbit with Epimetheus – and every four years the two swap places. That happens nowhere else.
Fact file
- Type
- Moon of Saturn
- Diameter
- 179 km
- Distance from Saturn
- 151,460 km
- Orbital period
- 0.7 days
- Temperature
- -195 °C on average
Janus orbits Saturn.
Interesting facts about Janus
- Janus shares its orbit with Epimetheus – and every four years the two swap places. That happens nowhere else.
- The orbits are only about 50 km apart; the inner moon slowly catches up with the outer one.
- Named after the Roman god with two faces – fitting for a moon with a “double life”.
Frequently asked questions about Janus
How big is Janus?
Janus has a diameter of 179 km. That is about 5.2% of the diameter of our Moon.
How far is Janus from Saturn?
Janus orbits Saturn at an average distance of 151,460 km.
How long does Janus take to orbit Saturn?
Janus orbits Saturn once every 16.7 hours.
How cold or warm is it on Janus?
On Janus the average temperature is −195 °C.
Formation
Janus and Epimetheus may once have been a single moon that broke up in a collision.
Atmosphere
No atmosphere.
Exploration
Discovered in 1966 by Audouin Dollfus, when Saturn's rings were seen exactly edge-on and their glare did not get in the way.
Compared with Earth
Around 180 km across – about the distance from Basel to Lugano as the crow flies.
Other moons of Saturn
This site is free and has no banner ads. Here is how you can support it