Comments on: Two Rings To Rule Them All: Amazing Space Discovery

By: Astrostevo

Astrostevo — Wed, 31 Dec 2014 04:35:48 +0000

I think this is indeed one of the most surprising and amazing discoveries of 2014.

Would never have guessed and staggered to find an asteroid can somehow maintain a ring system – would’ve thought it was far too low mass to do so.

Shared, great article and news – cheers and Happy New Year to Greg Laden & y’all.

By: Eric Lund

Eric Lund — Thu, 27 Mar 2014 14:01:50 +0000

G: Your model would give a single broad ring, rather than two narrow rings as reported. That doesn’t mean the rings aren’t the result of a collision, but rather that there must be something else going on as well. A shepherd moon, for instance (this is how some of the narrower rings at Saturn and Uranus are maintained).

The dynamical stability of this ring system is also an interesting question. How long does it take for rings like this to form, and how long do they last until something disrupts them? I don’t know the answers to those questions (it’s not my field), but they are important constraints on any theory of how these rings formed.

By: Greg Laden

Greg Laden — Thu, 27 Mar 2014 13:46:46 +0000

G: I don’t know. What I’ve heard is that the whole thing is a bit controversial, meaning that astronomers may disagree internally about how rings are formed. Perhaps these rings are impossible for some reason, i.e. because of the small size of the asteroid, by one or more major theories of how they form.

So get the popcorn out!

By: G

Thu, 27 Mar 2014 12:50:27 +0000

Layperson speculation on a mechanism:

Object A gets hit by Object B. Large quantity of debris is ejected and goes into orbit around Object A. The debris cloud elongates as it orbits.

The higher-mass debris ends up falling back to Object A (and depending on Object A being a rocky object, we might observe a band of returned debris around the circumference of Object A). The lower-mass debris ends up escaping Object A’s gravity and dispersing into space.

The debris that is of intermediate mass continues to orbit Object A. The interaction of angular momentum and gravity confines the debris to a narrow range of distance from the surface of Object A. And the tendency of everything toward dissipation, causes the debris cloud to diffuse as far as possible while staying within that range of distance.

The result of that interaction and dissipation, is the ring: an evenly-dispersed debris cloud at a particular orbit around Object A.

OK, feel free to tell me where I screwed up with that.