The new moon of Saturn

NASA's Cassini spacecraft has just discovered in the G ring of Saturn a small moon, which looks like a translucent bright light moving. Scientists believe it is the main source of the G ring and the only arc around it.

Cassini scientists analyzed the images obtained during the 600-day journey and discovered a very small moon, half a kilometer (about one-third of a mile) across, inside a bright arc. , previously found in Saturn's fuzzy G circle.

Matthew Hedman, of Cassini image analysis group at Cornell University, Ithaca, NY, said: 'Before Cassini, the G round was just a dust ring with no connection to a moon. This is a strange thing. The discovery of the small moon, along with other data from Cassini, will help us better understand this mystery. '

The rings around Saturn are named in the order they were discovered. From inside to outside include: D, C, B, A, F, G and E. The G ring is one of the external diffusion rings. Inside the translucent G ring there is a fairly light and narrow arc, 250 km (150 miles) wide, 150,000 km (90,000 miles), or 1/6 the circumference of the ring. A moon moves around this arc. Cassini's previous plasma and dust measurements show that this ring can be made from icy particles within the arc, such as the newly discovered moon.

The sequence of 3 images taken by NASA's Cassini spacecraft on a journey of about 10 minutes, shows the movement of a newly discovered moon in the arc of the Earth's G ring. (Photo: NASA / JPL / Space Science Academy)

Scientists captured the image of the moon on August 15, 2998, and they confirmed its presence by finding this object in two other photographs taken earlier. Since then they have observed the moon for many other times, most recently on February 20, 2009. This moon is so small that Cassini's camera cannot be resolved, so it cannot be measured. Next its size. However, Cassini scientists estimate the size of the moon by comparing its brightness to another moon Saturn, Pallene.

Hedman and his collaborators also found that the moon's orbit was hindered by Mimas, a nearby moon. Mimias has a role to fix the arc.

This finding puts Saturn's arc number with the Moon inside the figure 3. The newly discovered moon may not be the only moon in the arc G. Previous measurements with the device Cassini shows the existence of a set of elements, which can range in size from 1 to 100 meters. Hedman said: 'The impact of meteors, and collisions between these objects and the moon can release dust to form an arc'.

Carl Murray, a member of the Cassini image analysis team and professor at Queen Mary University of London, said: 'Discovering the new moon and the disturbance in its path caused by the nearby Mimas moon shows the close relationship between the moons and the arcs we observe in the Saturn system. Hopefully in the future we will learn how these arcs form and interact with the mother object '.

Early next year, Cassini's camera will observe the arc and the moon at a closer distance, the Cassini Equinox spacecraft will continue its journey until the fall of 2010.