[extropy-chat] re: Earth rings

[Amara Graps]

Earth has a dust ring that has been known already for some time.
This is resonant ring of asteroidal dust particles trapped in external
mean motion resonances with the Earth.

 From 10.10: the Earth's Dust Ring in _Solar System Dynamics_
by C.D. Murray and S.f. Dermott, Cambridge University Press, 1999,
pg. 522

"In many respects the asteroid belt behaves like a moonlet around the
Sun. We have already shown that is likely that collisions within the
belt have produced the Hirayama families of asteroids, recognised by
their clustering of proper elements (see sect. 7.10). Some of the dust
form the same collisions is also detectable as the bands detected by
the IRAS spacecraft (see Sect. 7.1.1). Any dust formed in the asteroid
belt will spiral in towards the sun due to the effects of PR drag.
Dermott et al. (1994) studied the orbital evolution of 12 micron dust
and showed htat it can get temporarily trapped in a series of exterior
first-order resonances with the Earth (see Fig. 10.29)"

also see:

S.f. Dermott et al: chapter: "Orbital Evolution" in the
book: _Interplanetary Dust_, editor: E. Gruen, b.A.S. Gustafson,
S.F. Dermott, H. Fechig, Springer Verlag, 2001, pg. 618-619.

and on the NASA ADS:
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1994aidp.work...16D&db_key=AST&high=413845eb0e03607
(you can download the PDF)

-- 

Amara Graps, PhD
Istituto di Fisica dello Spazio Interplanetario (IFSI)
Istituto Nazionale di Astrofisica (INAF),
Adjunct Assistant Professor Astronomy, AUR,
Roma, ITALIA     Amara.Graps at ifsi.rm.cnr.it