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Post by Chicago Astronomer Joe on Oct 19, 2004 3:04:54 GMT -6
From Astronomy Magazine, here is an image of the delicate rings that Cassini has imaged.
How fragile and gossemer they appear. I would like to see a mission in where a spacecraft probe would "Park" in just above or below the smaller particles and just observe the mechanics of the ring system.
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Post by Chicago Astronomer Joe on Aug 17, 2005 22:07:37 GMT -6
Saturn’s rings have own atmosphere
Data from the NASA/ESA/ASI Cassini spacecraft indicate that Saturn's majestic ring system has its own atmosphere - separate from that of the planet itself.
During its close fly-bys of the ring system, instruments on Cassini have been able to determine that the environment around the rings is like an atmosphere, composed principally of molecular oxygen. This atmosphere is very similar to that of Jupiter's moons Europa and Ganymede.
The finding was made by two instruments on Cassini, both of which have European involvement: the Ion and Neutral Mass Spectrometer (INMS) has co-investigators from USA and Germany, and the Cassini Plasma Spectrometer (CAPS) instrument has co-investigators from US, Finland, Hungary, France, Norway and UK.
Saturn's rings consist largely of water ice mixed with smaller amounts of dust and rocky matter. They are extraordinarily thin: though they are 250 000 kilometres or more in diameter they are no more than 1.5 kilometres thick.
Despite their impressive appearance, there is very little material in the rings - if the rings were compressed into a single body it would be no more than 100 kilometres across.
The origin of the rings is unknown. Scientists once thought that the rings were formed at the same time as the planets, coalescing out of swirling clouds of interstellar gas 4000 million years ago. However, the rings now appear to be young, perhaps only hundreds of millions of years old.
Another theory suggests that a comet flew too close to Saturn and was broken up by tidal forces. Possibly one of Saturn's moons was struck by an asteroid smashing it to pieces that now form the rings.
Though Saturn may have had rings since it formed, the ring system is not stable and must be regenerated by ongoing processes, probably the break-up of larger satellites.
Post by Chicago Astronomer Joe on Oct 28, 2005 0:12:25 GMT -6
Cassini reveals more about Saturn's F ring
Images of Saturn's narrow and contorted F ring returned by cameras onboard NASA's Cassini spacecraft have revealed phenomena not previously detected in any planetary ring. The findings are reported in Nature (27th October 2005).
The F ring is notorious for exhibiting unusual structures, like "knots," "kinks," and "clumps" that continue to puzzle astronomers. However, Cassini images have shown that the gravitational effect of the inner shepherding satellite, Prometheus, appears to produce regular patterns on the ring including a series of channels or gores and 'streamers' of particles that temporarily link the ring to the satellite. As an example of a satellite that enters a ring on a regular basis, the phenomena posed unique challenges to the understanding of ring-satellite interactions.
Post by Chicago Astronomer Joe on Nov 16, 2005 15:55:47 GMT -6
NASA Cassini Image: Graceful Lanes of Ice
The dark Cassini Division, within Saturn's rings, contains a great deal of structure, as seen in this color image. The sharp inner boundary of the division (left of center) is the outer edge of the massive B ring and is maintained by the gravitational influence of the moon Mimas.
This view is centered on a region approximately 118,500 kilometers (73,600 miles) from Saturn's center. (Saturn is 120,500-kilometers-wide (74,900 miles) at its equator.) From left to right, the image spans approximately 11,000 kilometers (6,800 miles) across the ringplane.
You're talking about individual grains of grit and ice. A lot of that's going to be hard to photograph. You'd have to be way up close, like taking a picture through a microscope, and at that range a ring would look like nothing at all probably. I'm just guessing on this. I'm fascinated about how these ring structues form. The other gas giants have them too, but only Saturn's is so dramatic.
If the universe is a ball the size of America, then the solar system is almost as large as the smallest cell in the human body.