IPB

Welcome Guest ( Log In | Register )

2 Pages V   1 2 >  
Reply to this topicStart new topic
New ring discovered around Saturn
alan
post Oct 7 2009, 12:25 AM
Post #1


Senior Member
****

Group: Members
Posts: 1887
Joined: 20-November 04
From: Iowa
Member No.: 110



QUOTE
The newly discovered ring spans from 128 to 207 times the radius of Saturn – or farther – and is 2.4 million kilometres thick. It was found using NASA's Spitzer Space Telescope, which revealed an infrared glow thought to come from sun-warmed dust in a tenuous ring.

The discovery was announced on Tuesday at a meeting of the American Astronomical Society's Division of Planetary Sciences in Fajardo, Puerto Rico. "This is a unique planetary ring system, because it's the largest planetary ring in the solar system," team leader Anne Verbiscer of the University of Virginia in Charlottesville told the meeting.

The source of the ring's material seems to be Saturn's far-flung moon Phoebe, which orbits the planet at an average distance of 215 times the radius of Saturn. When Phoebe is hit by wayward space rocks, the impacts could generate debris that fills the rings.

http://www.newscientist.com/article/dn1792...und-saturn.html

Go to the top of the page
 
+Quote Post
maschnitz
post Oct 7 2009, 03:01 AM
Post #2


Junior Member
**

Group: Members
Posts: 60
Joined: 3-January 09
Member No.: 4520



There's a nice illustration of it up already on Wikipedia:
http://en.wikipedia.org/wiki/Rings_of_Saturn#Phoebe_ring
Go to the top of the page
 
+Quote Post
brellis
post Oct 7 2009, 04:02 AM
Post #3


Member
***

Group: Members
Posts: 754
Joined: 9-February 07
Member No.: 1700



What a gorgeous discovery!

This is the kind of thing I wondered about when Cassini was first arriving at Saturn: are there some pebbles and ice cubes we can't see from Earth that Cassini might strike, either upon arrival or during one of its orbits?

Granted, the material in the Phoebe Ring must be spread quite thin, and it's quite far from Saturn, but Cassini flew by Phoebe on its way to Saturn in 2004. I wonder if they had any idea then that Phoebe might be feeding a ring of its own!
Go to the top of the page
 
+Quote Post
Julius
post Oct 7 2009, 04:18 AM
Post #4


Member
***

Group: Members
Posts: 362
Joined: 13-April 06
From: Malta
Member No.: 741



Could it be that Phoebe is a captured burnt out comet!?? blink.gif
Go to the top of the page
 
+Quote Post
Guest_PhilCo126_*
post Oct 7 2009, 10:23 AM
Post #5





Guests






Here's another drawing:
Go to the top of the page
 
+Quote Post
stevesliva
post Oct 7 2009, 12:12 PM
Post #6


Senior Member
****

Group: Members
Posts: 1576
Joined: 14-October 05
From: Vermont
Member No.: 530



Still an artist's impression. But the article said the discovery was made using Spitzer when it still had cryogen, and that the observations were of basically empty space.
Go to the top of the page
 
+Quote Post
imipak
post Oct 7 2009, 12:31 PM
Post #7


Member
***

Group: Members
Posts: 646
Joined: 23-December 05
From: Forest of Dean
Member No.: 617



There's a great interview with Dr Verbiscer on BBC Radio 4's "The World at One" current affairs programme:

http://www.bbc.co.uk/programmes/b006qptc

Starts about 26 minutes in. The "Listen Again" links for the 7th October should, I think, work outside the UK.

(Edit - corrected spelling of Dr Verbiscer's name. Twice! D'oh rolleyes.gif )


--------------------
--
Viva software libre!
Go to the top of the page
 
+Quote Post
Rob Pinnegar
post Oct 7 2009, 02:33 PM
Post #8


Member
***

Group: Members
Posts: 509
Joined: 2-July 05
From: Calgary, Alberta
Member No.: 426



QUOTE (Julius @ Oct 6 2009, 10:18 PM) *
Could it be that Phoebe is a captured burnt out comet!?? blink.gif

If I recall correctly, the general feeling is that it is most likely a captured Centaur (an object similar to 2060 Chiron), which somehow ended up in orbit around Saturn.

Centaurs often end up turning into short-period comets, so it's possible that Phoebe *would* have ended up as a burnt-out comet if Saturn hadn't nabbed it first. But it could also have wound up getting thrown into the Sun, or right out of the solar system altogether, probably by Jupiter. (When you're a small Solar System body, messing with Jupiter is a *bad* idea. It never turns out well.)
Go to the top of the page
 
+Quote Post
maschnitz
post Oct 7 2009, 05:23 PM
Post #9


Junior Member
**

Group: Members
Posts: 60
Joined: 3-January 09
Member No.: 4520



Hyperion appears to be more like a burnt-out comet - not dense at all (half the density of water), and very porous.

Some of the press coverage was saying that micrometeor impacts cause the ring, not solar radiation. Still, I think of this like a captured comet with its tail wrapped around Saturn.
Go to the top of the page
 
+Quote Post
dilo
post Oct 7 2009, 05:33 PM
Post #10


Senior Member
****

Group: Members
Posts: 2492
Joined: 15-January 05
From: center Italy
Member No.: 150



This is the last present from cryo-Spitzer... sad.gif
Interestingly, the ring coul be the source of Iapetus dark material!


--------------------
I always think before posting! - Marco -
Go to the top of the page
 
+Quote Post
centsworth_II
post Oct 7 2009, 06:39 PM
Post #11


Senior Member
****

Group: Members
Posts: 2173
Joined: 28-December 04
From: Florida, USA
Member No.: 132



QUOTE (dilo @ Oct 7 2009, 12:33 PM) *
Interestingly, the ring could be the source of Iapetus dark material!

Googling a bit, I see that [Phoebe] has long been looked at as a possible source for the dark material on Iapetus, but the spectroscopy did not match up. Maybe the dark Iapetus material has other sources in addition to Phoebe, or maybe the material in the ring is altered somehow before it lands on Iapetus:
"...based on spectral comparison only, Phoebe does not appear to be the elusive source. Because material from Phoebe could conceivably undergo alteration upon transference or arrival to Iapetus, our new data do not preclude the possibility of Phoebe as a source for Iapetus dark material...."

I don't know if the discovery of the ring was a surprise or just a case of looking hard to see something that was suspected to be there. Maybe it was not known if material from Phoebe formed a ring or just a tail. I don't know how strong the suspicions were either way, or if the size of the ring is a total surprise.
Go to the top of the page
 
+Quote Post
ngunn
post Oct 7 2009, 09:00 PM
Post #12


Senior Member
****

Group: Members
Posts: 3516
Joined: 4-November 05
From: North Wales
Member No.: 542



What's special about Phoebe? If the material is thrown off by impacts then why don't all moons make rings? Why hasn't our moon made a ring around Earth?

Maybe the origin is primordial and Saturn has it's own miniature Kuiper belt. Phoebe would then be just the largest TIO.
Go to the top of the page
 
+Quote Post
volcanopele
post Oct 7 2009, 10:13 PM
Post #13


Senior Member
****

Group: Moderator
Posts: 3225
Joined: 11-February 04
From: Tucson, AZ
Member No.: 23



I don't think there is anything special about Phoebe. It just happens to be large enough to throw enough material into space with micrometeorite impacts that its co-orbital ring is visible to Spitzer. I would not be surprised if the other small detritus out in the outer Saturn system (and the other outer planet systems) have similar, but much fainter, rings. Keep in mind that the proposed scenario put out be Verbiscer et al. is akin to what is going on at Janus and Epimetheus, Pallene, Methone and Anthe, Aegaeon, Mab, and Adrastea and Metis.

The reason it doesn't happen on the Moon is that the Moon is massive enough that most impact ejecta re-accretes back onto the Moon. For these little guys, like Phoebe, they are too small to hold on to much of the ejecta from micrometeorite impacts, and dust from these impacts goes into orbit around the parent planet.


--------------------
&@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io
Go to the top of the page
 
+Quote Post
SFJCody
post Oct 7 2009, 10:19 PM
Post #14


Member
***

Group: Members
Posts: 813
Joined: 8-February 04
From: Arabia Terra
Member No.: 12



Maybe Neptune's large irregular Nereid also has a ring associated with it. huh.gif
Go to the top of the page
 
+Quote Post
Gsnorgathon
post Oct 7 2009, 10:23 PM
Post #15


Member
***

Group: Members
Posts: 259
Joined: 23-January 05
From: Seattle, WA
Member No.: 156



Would Phoebe's retrograde orbit contribute to the production of ring particles? Would it result in higher impact velocities with whatever bits of stuff happened to be whizzing by?
Go to the top of the page
 
+Quote Post

2 Pages V   1 2 >
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 19th March 2024 - 04:58 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.