ESA image: Saturn's moon Rhea, Epimetheus transiting

August 12, 2014
Credit: NASA/JPL-Caltech/Space Science Institute; Processed image copyright: G. Ugarković

Saturn has a great many more moons than our planet – a whopping 62. A single moon, Titan, accounts for an overwhelming 96% of all the material orbit the planet, with a group of six other smaller moons dominating the rest. The other 55 small satellites whizzing around Saturn make up the tiny remainder along with the gas giant's famous rings.

One of the subjects of this Cassini image, Rhea, belongs to that group of six. Set against a backdrop showing Saturn and its intricate system of icy rings, Rhea dominates the scene and dwarfs its tiny companion, one of the 55 small satellites known as Epimetheus.

Although they appear to be close to one another, this is a trick of perspective – this view was obtained when Cassini was some 1.2 million km from Rhea, and 1.6 million km from Epimetheus, meaning the moons themselves had a hefty separation of 400 000 km.

However, even if they were nearer to each other, Rhea would still loom large over Epimetheus: at 1528 km across and just under half the size of our own Moon, Rhea is well over 10 times the size of Epimetheus, which is a modest 113 km across.

As is traditional for the earliest discovered moons of Saturn, both are named after figures from Greek mythology: the Titan Rhea ("mother of the gods") and Prometheus' brother Epimetheus ("after thinker" or "hindsight").

This image was taken by Cassini's narrow-angle camera on 24 March 2010, and processed by amateur astronomer Gordan Ugarković.

Explore further: Image: Bright are Saturn's moons

Related Stories

Image: Bright are Saturn's moons

July 6, 2011

The Cassini spacecraft observed three of Saturn's moons set against the darkened night side of the planet in this image from April 2011.

Image: Closest Dione flyby

January 23, 2012

(PhysOrg.com) -- Flying past Saturn's moon Dione, Cassini captured this view which includes two smaller moons, Epimetheus and Prometheus, near the planet's rings.

Image: Rhea before Titan

February 16, 2012

(PhysOrg.com) -- Craters appear well defined on icy Rhea in front of the hazy orb of the much larger moon Titan in this Cassini spacecraft view of these two Saturn moons.

Image: Quintet of moons

November 5, 2013

(Phys.org) —Five moons pose for the international Cassini spacecraft to create this beautiful portrait with Saturn's rings.

Saturn's moon Atlas shines between gas giant's rings

June 18, 2014

See that small pixel? That's an entire moon you're looking at! Peeking between the rings of Saturn is the tiny saucer-shaped moon Atlas, as viewed from the Cassini spacecraft. The image is pretty, but there's also a scientific ...

Cassini prepares for its biggest remaining burn

August 8, 2014

(Phys.org) —NASA's Cassini spacecraft will execute the largest planned maneuver of the spacecraft's remaining mission on Saturday, Aug. 9. The maneuver will target Cassini toward an Aug. 21 encounter with Saturn's largest ...

Recommended for you

New Horizons team selects potential Kuiper Belt flyby target

August 29, 2015

NASA has selected the potential next destination for the New Horizons mission to visit after its historic July 14 flyby of the Pluto system. The destination is a small Kuiper Belt object (KBO) known as 2014 MU69 that orbits ...

Ceres image: The lonely mountain

August 25, 2015

NASA's Dawn spacecraft spotted this tall, conical mountain on Ceres from a distance of 915 miles (1,470 kilometers).

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Requiem
not rated yet Aug 14, 2014
And what does this have to do with ESA?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.