I've been hooked into this forum for a few months and finally have a question worth submitting. I've been educated with the typical science background of asteroids = rocks, comets = ice balls, and am certainly not an expert in space oriented discussions. After watching the majority of the EU conference youtube vid's, and science news youtube vid's, as well as "Episode 3 Symbols of an Alien Sky: The Electric Comet (Full Documentary)" ...
Using wiki to find the official definitions of solar system bodies, I stumbled upon the IAU (International Astronomical Union) website, where they appear to set the definition of said things.
http://www.iau.org/news/pressreleases/detail/iau0603/#3
Comets are small solar-system bodies because they do not meet criteria (b) nor (c) and associated with the notion of "ice" and the "coma".RESOLUTION 5A
The IAU therefore resolves that planets and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:
(1) A "planet" [1] is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
(2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape [2], (c) has not cleared the neighbourhood around its orbit, and
(d) is not a satellite.
(3) All other objects [3], except satellites, orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies"."
http://www.iau.org/public/themes/naming/
Interestingly, the IAU website does not appear to define "Small Solar-System Bodies" very well, it is just a catch-all for the things they have defined they are not (aka - not a planet, not a satellite, its a SSSB). Comets are delineated from the others SSSB's with their noticeably observable effects. Also note, non-comet small solar-system bodies are those defined as not made of "ice", and not displaying a "coma", but nothing else. In fact the IAU website goes on to describe how to name them, not how to define them. It is defined by the elimination of their other criteria.Comets
A comet is a body made of rock and ice, typically a few kilometres in diameter, which orbits the Sun. Comets may pass by the Sun only once or go through the Solar System periodically. A comet’s tail is formed when the Sun’s heat warms the coma or nucleus, which releases vapours into space.
An image for clarity (credit wikipedia/Tahc)Minor Planets
The assignment of a particular name to a particular minor planet is the end of a long process that can take many decades:
Are asteroids (small solar system bodies) and comets the same thing (from an EU perspective)?
If we are to red-line (remove ICE) from the (IAU) definition of the comet, the distinction between those which "are" and "are not" comets will reside solely on the observation of the "coma". From what I have read on this forum, there is no material difference with comets and other bodies. There is only a difference in orbit, where I see it argued, the orbit as the leading cause of the coma due to "increased charge density" from the electric sun. (credit Rossim)
Said differently, are there any asteroids with comet-like orbits which do not display comet like features (coma)?
"Asteroids*: 643,800 (401,521 numbered**, 242,279 provisional)
Comets***: 5,186 (305 numbered***, 3,515 with provisional designations, 1,366 without designations)"
A ratio of 1 comet to 125 asteroids in our solar system.
Nick