Asteroids

[Max Photon]

Dotini and Nick,

While I am sympathetic with your posts, regardless of what we think of the individual hypotheses put forth in that article, the point I'm making is that they brought up electricity as a possible explanation, but unless I missed it, they dismissed dismissing it. They brought it up and then... voila!... ignored it.

With slight of ... mind ... they -- "we" -- are left with mass shedding from solar-driven rotation.

(And I don't suspect any of us are impressed with the notion of smeared out dust rays that brighten and dim and rotate like a lawn sprinkler.)

[viscount aero]

The mass shedding as a result of fast rotation hypothesis is really bad. They must be desperate to come up with that one.

Yes that explanation is typical nonsensical "sci-prattle" that in actuality--when actually examined and not just barely read as most would do--makes no logical sense whatsoever.

Why would a rapidly rotating object throw off material in the form of cometary tails?

Exactly. It wouldn't. Why would it? For that matter, all rapidly rotating objects should have multiple cometary tails. But that is not the case. It is as if they are trying to find a correlation between premature baldness and eating chocolate ice cream. Therefore the explanation is not only erroneous but stupidly erroneous.

Would it not simply be surrounded by a roughly spherical cloud of dust and debris?

Yes and it would also show a sprial pattern near the body of the asteroid/comet. But wait... isn't this coming from a scientifically authoritative source? If so then why are such explanations given when they have no scientific basis?

[Max Photon]

They brainstormed four possible mechanisms, discounted two, ignored one, and said the remainder (though there were really two remainders -- one electric! -- but ignore that) -- mass shedding due to rotation was the wiener, I mean, winner.

[Sparky]

In a parody of SNL, "Cow bells, I need more cow bells!"....

Comet tails, we need more tails!

[viscount aero]

In a parody of SNL, "Cow bells, I need more cow bells!"....

Comet tails, we need more tails!

[StefanR]

Nice paper to chew on...
Gives a nice example of the different proposed mechanisms of "mass-loss" and elaborates on them.
It seems as if they just don't have a good model for the electrostatic interaction.
By the way, I'm still not quite sure if perhaps the dust itself could play a role in regulating
of the discharge activity. It must have certain properties that differ from the 'regolith' or 'surface'
of the bodies concerned. Does the dust isolate the surface from interaction or does it enhance its
capacitive function as a whole? Is there a certain threshold between bare surface area and area
covered by dust? Do any of you perhaps have ideas about that?

THE ACTIVE ASTEROIDS
ABSTRACT
Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the
sublimation of near-surface water ice, mass-losing asteroids (also called “main-belt comets”) can in fact be driven
by a surprising diversity of mechanisms. In this paper, we consider 11 dynamical asteroids losing mass, in nine
of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including
rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses,
and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of
the observed activity leaves ice sublimation as the only reasonable explanation, while in a third ((596) Scheila),
a recent impact is the cause. Another impact may account for activity in P/2010 A2, but this tiny object can also
be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is probably
due to cracking or dehydration at extreme ("1000 K) perihelion temperatures, perhaps aided by radiation pressure
sweeping. For the other bodies, the mass-loss mechanisms remain unidentified, pending the acquisition of more
and better data. While the active asteroid sample size remains small, the evidence for an astonishing diversity of
mass-loss processes in these bodies is clear.
[....]
6. SUMMARY
The number of mechanisms capable of producing mass loss
from asteroids rivals the number of asteroids showing evidence
for mass loss. No single mechanism can account for the varied
examples of activity observed, but preferred explanations can
be suggested for particular objects.
1. Sublimation of crystalline ice is effective to the outer edge
of the asteroid belt and in asteroids up to a few 100 km
in size. Observational evidence for the sublimation of
water ice is strongest in the two repeatedly active objects
133P/Elst–Pizarro and 238P/Read.
2. Activity in (596) Scheila is unambiguously caused by the
impact of a decameter-sized projectile, as indicated by the
photometric and morphological evolution of this body.
3. Rotational instability is likewise broadly operable, but it is
the sub-kilometer asteroids that are most likely to be driven
toward instability by YORP effects. The 120 m diameter
P/2010 A2, if it is not also an impact relic, could be a
rotationally disrupted body.
4. Thermal fracture and dehydration cracking are expected to
supply dust particles only on asteroids that are very close to
the Sun ()1 AU) and smaller than about 20 km. Radiation
pressure sweeping can remove grains from 10 km asteroids
up to 3 AU but is more effective at smaller distances.
All these processes may operate in small perihelion object
(3200) Phaethon.
5. Ejection of optically active grains (i.e., > 0.1μm) by the
electrostatic mechanism is possible for asteroids up to about
10–20 km in radius with an efficiency that is independent
of heliocentric distance. No clear examples of this process
have been identified.
6. The causes of mass loss from the other active asteroids
cannot be reliably determined given the limited available
data (see Table 3).

http://www2.ess.ucla.edu/~jewitt/papers/2012/J12.pdf
from here:
Main Belt Comets = Active Asteroids
http://www2.ess.ucla.edu/~jewitt/mbc.html

[Sparky]

By the way, I'm still not quite sure if perhaps the dust itself could play a role in regulating of the discharge activity.

The ion filled dust ( assumption) would be conductive and be conducting to and from the asteroid wouldn't it? The coma and tails provide a huge area to connect to areas of differing potentials.

Tails, We need more tails!

[Max Photon]

StefanR, thanks for the great links.

I love the line in the ABSTRACT:

In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation...

In sales that's called the "assumptive close."

[Max Photon]

Space News from the Electric Universe has a new video on P/2013 P5.

Astonishing Asteroid Becomes a Comet

[viscount aero]

StefanR, thanks for the great links.

I love the line in the ABSTRACT:

In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation...

In sales that's called the "assumptive close."

They're still firmly deathgripped onto the dirty snowball idea! They're so behind in their applied knowledge it is a comedy

[Max Photon]

In the thread on Comet ISON, Sparky brought up that the Great Comet of 1744 displayed six tails.

Wikipedia > The Great [6-Tailed] Comet of 1744

P/2013 P5 has six tails.

In Talbott's video Symbols of an Alien Sky, Venus had, at times, six tails.

[Sparky]

Yes, multiple tails!! ...What does that suggest?

Possibly a greater current flow within the tails, and their interaction with the solar wind displacing and sorting the different magnetic fields by strength. ireallydonno

[Dotini]

Wikipedia > The Great [6-Tailed] Comet of 1744

This article notes that Chinese astronomers "describe audible sounds associated with the comet, which may, if true, have resulted from the interaction of particles with the Earth's magnetosphere, as sometimes described for the aurora.[7]"

It is worth mentioning here that strange booming sounds have been reported worldwide since the early summer of 2011.
http://strangesounds.org/2013/05/strang ... booms.html

NASA is reporting no less than 31 fireballs for November 19, 2013 and no less than 4 bright comets rising in the east before dawn.
http://spaceweather.com/

To cap this post off, an interesting story about a "rare white raven" found in Greenland. http://www.nunatsiaqonline.ca/stories/a ... servation/
White ravens have a special place in world mythology, legend, lore and symbolism as an omen, or portent. Bright comets, of which there are four currently in the solar system, have been viewed similarly in the past as omens of crisis in the spiritual or physical worlds - and in the realms of man.

Respectfully submitted,
Steve

[dahlenaz]

Comet ENKE's tail activity, seen in this Spceweather.com animation, sure tells more
than a single pictures.. Many people are using an image stacking method
to process celestial images and cemoets,,,even those may fall short of
showing what is really happening in the tail region..

What is all that dancing about??? d...z

http://spaceweather.com/images2013/22no ... ncdghsqne1

[Rossim]

I'm sorry if this has been addressed but NASA has the eccentricity of the orbit at 0.1152, which is pretty close to a perfect circle. Any explanations?