Definition of a planet (9)

1 Name: Sling!XD/uSlingU 2005-09-22 18:02 ID:tQL09r0U
"A 19-member working group within the International Astronomical Union has been scrambling ever since to reach consensus, but to no avail.

The main sticking point: If Pluto is a planet, then so is 2003 UB313, the object discovered in July. But by that logic, there are several other round objects nearly as big as Pluto that should be considered planets, some astronomers say.

The compromise currently being floated by the working group is to add an adjective in front of the term planet for each different type of non-stellar round object.

Pluto and 2003 UB313 could be called Trans-Neptunian objects. Earth would be called either a terrestrial planet or perhaps a "cisjovian" planet, meaning it's inside Jupiter.

Further complicating the matter are extrasolar planets much more massive then Jupiter, planet-like objects orbiting dead stars called pulsars, and possibly even free-floating worlds that don't orbit stars."

D'oh. Are they afraid to upset astrologists of what?
The standard definition is very straightforward:
"A nonluminous celestial body larger than an asteroid or comet, illuminated by light from a star, such as the sun, around which it revolves."

2 Name: Sling!XD/uSlingU 2005-09-22 18:04 ID:tQL09r0U

>>1 s/astrologists of what/astrologists or what/

3 Name: Ichigo Pie!5ouPkmz/WI 2005-09-22 18:20 ID:v+57Lr/7

I think you might have accidentally insulted a large group of astronomers just now...

4 Name: Sling!XD/uSlingU 2005-09-22 21:13 ID:tQL09r0U

My horoscope tells me that 2003 UB313 is having a bad influence, which makes me prone to heedlessness and lack of precision. :)

5 Name: Mad Scientist 2005-10-06 03:23 ID:rKpR1Hg2

Funny thing is, with that definition, the colder of brown dwarfs (which are still luminous if they're undergoing fusion, iirc) wouldn't be either stars or planets.

6 Name: Sling!XD/uSlingU 2005-10-06 14:34 ID:Con1gn2o

Which definition? The one I gave in >>1?
My definition says "nonluminous". If the dwarf is still luminous then it isn't nonluminous. The problem would be when the dwarf is fully nonluminous, but then it could be called an ex-star or a dead star or whatever, referring to its previous status.

7 Name: Anonymous Scientist : 2006-03-08 11:11 ID:wjpuA9M9

But at some point in time, even though perhaps taking billions of years, such an extinguished star would eventually end up in orbit around another star. So it'll be a planet. But the definition of planet is only usefull if you can relate it to the star it is orbiting right now, so that isn't much use.

Why can't we just acknowledge that there are more entities in space than what is covered by limited human terminology? I sure won't be offended!

8 Name: Anonymous Scientist : 2006-03-08 14:37 ID:Heaven

Correctly identifying planets is important for matters of buerocracy, such as proper taxation of planetary resources, and various kinds of grants and support payments.

9 Name: Anonymous Scientist : 2006-03-09 00:46 ID:wjpuA9M9

bureaucracy. And don't forget meteor impact tax! Remember that's 35% of impact velocity in dollarmeter/secon multiplied by the radius of the mass if it were restructured to a perfect sphere (in meters). Now if a meteor could be a planet, or vice versa, this simple formula is completely unfair to say the least. Whereas the scale of collision remains the same, the bill sent to the owner of the body guilty of collision is on a completely different level. This kind of ambiguity is unacceptable as it gives scope to littering space with dangerous planets/meteores only because punishment of accidents are open to debate.

In a cryout for justice and in the name of all law-fearing earthbound citizens I must thus demand a quick and decisive definition of planet and other non-celestial bodies.

thank you

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