[meteorite-list] There IS an Earth Trojan Asteroid (probably)!

[MexicoDoug at aol.com]

Ron B. wrote:
 
>Sterling W. wrote:
>>"The near-Earth asteroid 3753 Cruithne is  in an unusual orbit about
>>that of the Earth, one which is known in  the lingo of celestial
>>mechanics as being co-orbital with the Earth  (meaning it SHARES [my
>>emphasis] the Earth's orbit with it) and, more  particularly, as being of
>>the "horseshoe" type. 

>'Share'  is a bad choice of word, since Cruithne does not share an orbit 
with  Earth.
 
Rod Serling List,
 
Earth does share two-body acrobatics transfering momentum back  and forth 
across the Solar axel with Cruithne in a basically three-body system  causing 
this "RESONANCE" and causing an orbital SHARING of MOMENTUM, but  not of PATH.
 
At only 5 km estimated diameter of Cruithne, it is relegated  to a species of 
space rubble, that could have an infinite number of other  orbital paths that 
looked very different to its and Earth's current orbit and  still share mome
ntum equally or even more, performing amorous mechanical  contortions.  What we 
don't share is an orbital trajectory until someone  wants to make an 
interesting story from informationless averages (over  many orbits, average year = 1, 
average distance = 1 AU).
 
So, the Cruithine folk are probably scratching their kneecaps now saying  
"those third two huge piles of rocks are gonna direct our orbit again and  we'll 
be headed for another cool age in two or three centuries - maybe we  ought to 
nuke 'em and be decoupled once and for all."  Note that from the  asteroid's 
point of view Earth is an integral determining factor of its orbit  which 
cannot be determined by the Sun alone, and in that sense is co-orbital,  
manifesting repetitiously over orbits the same shared gravitational  interactions.
 
Cruithne currently has a perihelion of less than 0.5 AU and an aphelion of  
over 1.5 AU and, :-) is covered in pictographs.
 
Saludos, Doug