What constitutes a Solar System?

[rogers_buck]

No, Jupiter would require the additional mass of 10**10 ,monoliths before it would have a high-enough pressure at its core for the odd fusion reaction to occur with any of the catalyzed reactions I know of.<br /><br />However, probabilities being what they are, I don't think it can be said that NO fusion reaction EVER occurs in a gas ball like Jupiter. So, maybe a lower limit needs to be defined. <br /><br />Maybe #4 should be amended so as to state that fusion cannot be the primary heat source from within the body. Fission is OK, gravitational collapse is OK, so long as rule 4 was not violated in said objects history.<br /><br />But among reasonable people, I think #4 is fine as stated.<br /><br />That should comfortably exclude all objects attempting to masqarade themselves as planets.

 

[Maddad]

Silylene<br />"<font color="yellow">To be a planet: <br />1. object has to orbit a star or stars, and not be a satellite of an object orbiting a star(s) <br />2. has to have a persistent orbit <br />3. has to be massive enough to be spherical (if it were not rotating, e.g. Saturn is distinctly non-spherical) <br />4. cannot be so massive as to support fusion <br />5. has to be considered a planet by popular acclimation. I know, this is non-technical, but that's the way it is (just like a tomato is a vegetable and not a fruit). Thus Pluto is a planet and Quorar (sp?) is not included</font><br /><br />And that's probably the best answer yet.

 

[Grok]

kpsting,<br /><br />Where do you get your definition of a solar system being a planetary system? Is that just your opinion or is it backed by science? What type of system is a system which only has asteroids and non planetary objects?

 

[nexium]

kpsting and wicpedia make a lot of sence, however, I would expect that every star would be orbited by more than a few sub atomic particles, if not larger stuff, so calling it a solar system is not unreasonable. My guess is we waste a lot of human talant trying to define things very precicely. As one wise person said: the exceptions help prove the rule. Neil

 

[nexium]

I have some problems with those 5 rules, especially 1 and 2. If some planets are ejected from the system by a near collision, do they cease to be planets while they orbit the galaxy instead of a star?<br /> In 1 you said "or stars" "Planets" that orbit the galaxy orbit billions of stars, and planets that orbit the galaxtic group orbit a trillion or more stars.<br /> In another tread, last year, an astronomer defined everything not main sequence as not a star. Does that mean planets cannot orbit a white dwarf or black hole?<br /> Does "persistant" = one thousand years or one billion years? We would need an additional set of guide lines to guess the orbit is likely to persist with 90% probability, for a specific number of years. Sorry to nit pick but these sort of questions will occur if we try to classify a few billion bodies as planets or not planets. Neil