[Outbackmanyep]

Originally Posted by Jarvamundo

Don Yeoman quote has summed it up very well indeed.....

Electric comets - Predominately rock comet, Electrostatic discharges, forming threads of charged particles (plasma) as the tail, minimal ice.... tails mainly not due to suns heat.

Standard model "Whipple" - Sublimating ice from the suns heat... dirty snowball, icey dirtball melts and forms tail.

2 clear models... it is clear consensus needs to change.

OK, i am NOT pushing any conspiracy point, i'm open minded but not to the point where things just don't make sense.

Comets interact with the solar wind, solar wind = charged particles streaming from the Sun along magnetic field lines, this is what interacts with sublimated ices (not melted) the molecules of which are photoionised by sunlight, the charged particles from the solar wind gently repel these ions behind the comet, this is a Type 1 tail, an ION TAIL. This tail always points directly away from the sun.

Cometary DUST tails are minute particles RELEASED from ices bound with dust upon sublimation of the ices. When dust is released from the sublimated ices it forms into a tail with respect to the orbit of the comet, ie: it follows the comets path through space, sunlight acts on these particles which gently perturbs the spread of the finer material. These particles are very small and only interact with certain wavelengths of sunlight, larger particles (mm in size) follow the orbit of the comet close to the path of the nucleus.
Dust tails can be moderately curved (Type 2) or strongly curved (Type 3) depending on various orbital mechanics of the comet, they also point away from the sun but not directly. The visibility of dust depends on it's production rate.


So we understand that there are indeed electro-magnetic and gravitational components to a comet through interaction with solar wind and sunlight, as well as a third which is a non-gravitational effect. In relation to Whipple's Dirty snowball model which he used to discard the "orbiting gravel bank" idea, the understanding of how a comet behaves is still being tried and tested today but the basis which Whipple started the whole debate about "dirty snowball" comets is the most widely accepted amongst astronomers, and is being refined all the time .
I have read about the electrostatic effects on the surface of a comet (leviatation of dust and build-up of electrostatic charge and flow), which could explain one trigger for outbursts, but as far as i know, unless an in-situ observation is done, it is still only a theory!