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Fraser
2006-Nov-17, 01:56 AM
This Cassini photograph shows particles from Saturn's F ring streaming after its moon Prometheus. Even though the moon is only 102 km (63 miles) across, its gravity has this kind of an effect on the ring particles. Astronomers are looking forward to 2009, when the moon will travel into the F ring's core, plowing straight through the particles. Cassini took this photo on Oct.16, 2006 when it was 1.8 million kilometers (1.1 million miles) from Prometheus.

Read the full blog entry (http://www.universetoday.com/2006/11/16/ring-particles-chasing-prometheus/)

antoniseb
2006-Nov-17, 12:13 PM
Prometheus plowing into the F ring should provide some interesting information about particle size.

iantresman
2006-Nov-19, 12:05 AM
This Cassini photograph shows particles from Saturn's F ring streaming after its moon Prometheus.

Anyone know why the particles "stream"? Shouldn't gravitational forces affect ring particles both in front as well as behind the moon resulting in a fan-shaped, rather than cylindrical stream. Or is this an illusion?

Regards,
Ian Tresman

VanderL
2006-Nov-19, 08:43 PM
Anyone know why the particles "stream"? Shouldn't gravitational forces affect ring particles both in front as well as behind the moon resulting in a fan-shaped, rather than cylindrical stream. Or is this an illusion?

Regards,
Ian Tresman

Do we even know for sure that the particles are streaming towards Prometheus and are not being released by the moonlet (as seems to be happening with Enceladus)?

Cheers.

antoniseb
2006-Nov-19, 09:33 PM
Do we even know for sure that the particles are streaming towards Prometheus and are not being released by the moonlet (as seems to be happening with Enceladus)?

It is at least as likely that they are neither streaming toward, nor away, but rather concentrating by having a small differential movement in a direction orthogonal to the stream.