Starship Asterisk*

The 5-mile-wide (8-kilometer) moon Daphnis orbits within the 26-mile-wide (42-kilometer) Keeler Gap in Saturn's outer A ring, and its gravitational pull perturbs the orbits of the particles forming the gap's edges. The eccentricity, or the elliptical deviation from a circular path, of Daphnis' orbit can bring it close to the gap edges. There, its gravity causes larger effects on ring particles than when it is farther away. Previous Cassini images have shown that as a consequence the moon's effects can be time-variable and lead to the waves caused by Daphnis to change in shape with time and with distance from the moon.

However, the new analysis also illustrates that when such a moon has an orbit inclined to the ring plane, as does Daphnis, the time-variable edge waves also have a vertical component to them. This result is backed by new images taken recently near equinox that show the shadows of the vertical waves created by Daphnis and cast onto the nearby ring match the characteristics predicted by the new research.

bystander wrote:

aristarchusinexile wrote:How do I go about getting permission to use that stuatue on the label?

I'm not sure that's a good idea. It would make the bottles rather heavy and unwieldy.

aristarchusinexile wrote:How do I go about getting permission to use that stuatue on the label?

http://en.wikipedia.org/wiki/Prometheus' wrote:
<<Prometheus (Ancient Greek: Προμηθεύς, "forethought") was a champion of human-kind known for his wily intelligence, who stole fire from Zeus and gave it to mortals. Zeus then punished him for his crime by having him chained to a Rock(efeller Center) in the Caucasus, while a great eagle ate his liver every (15 hour) day only to have it grow back to be eaten again the next day. Years later the Greek hero Heracles (Hercules) would shoot the vulture and free Prometheus from his chains.>>

Prometheus Orbital period: 	14.71 hours
Prometheus Rotation period: 	synchronous

http://apod.nasa.gov/apod/ap090427.html wrote:
Explanation: <<Prometheus orbits Saturn just inside the thin F-ring, but ventures into its inner edge about every 15 hours. Prometheus' gravity then pulls the closest ring particles toward the 100-km moon. The result is not only a stream of bright ring particles but also a dark ribbon where ring particles used to be. Since Prometheus orbits faster than the ring particles, the icy moon pulls out a new streamer every pass.>>

Frenchy wrote:If Prometheus is an asteroid type body, does this mean that it originated from the asteroid or Kuiper belt? (I'm not sure of scale of distances of both from Saturn)

Frenchy wrote:If Prometheus is an asteroid type body, does this mean that it originated from the asteroid or Kuiper belt? (I'm not sure of scale of distances of both from Saturn)

Umbobo wrote:So, am I to understand the cornflake shaped entity in the upper left of this APOD frame is indeed the moon Prometheus? Pretty bizarre shape.

Tino wrote:Thanks for your answer Chris. Do you happen to know if the 15 hour period between Prometheus' forays into the edge of the F-ring are regular intersections of its elliptical orbit, or is it something else?

Chris Peterson wrote: Your understanding of the physics is correct (I'd say it a little differently, that the orbit radius is a function of orbital speed). The reason that Prometheus has a greater orbital speed than the F-ring is because it is closer to Saturn. In fact, the inner F-ring is orbiting faster than the outer F-ring.

Tino wrote:Even though Prometheus is vastly larger than the particles that make up the F-ring I don't understand how it is that they orbit at different speeds. I thought that orbital speed was a function of altitude but not mass. Can somebody explain this to me? Thanks in advance.