منابع مشابه
Shock synthesis of quasicrystals with implications for their origin in asteroid collisions.
We designed a plate impact shock recovery experiment to simulate the starting materials and shock conditions associated with the only known natural quasicrystals, in the Khatyrka meteorite. At the boundaries among CuAl5, (Mg0.75Fe(2+) 0.25)2SiO4 olivine, and the stainless steel chamber walls, the recovered specimen contains numerous micron-scale grains of a quasicrystalline phase displaying fac...
متن کاملDetermination of asteroid masses
The masses of the three largest asteroids: (1) Ceres, (2) Pallas and (4) Vesta were determined from gravitational perturbations exerted on respectively 25, 2, and 26 selected asteroids. These masses were calculated by means of the leastsquares method as weighted means of the values obtained separately from the perturbations on single asteroids. Special attention was paid to the selection of the...
متن کاملStability of Asteroid Motions
In this paper it is explained how most of asteroids can avoid very close approach to Jupiter, to the earth for earth orbit crossing asteroids, and to Neptune for Kuiper-belt asteroids by mechanisms which work also for Neptune-Pluto system. In fact the mutual distance of the planets cannot become very small as the critical argument librates around 180 0 because of 2:3 mean motion resonance and t...
متن کاملThe Asteroid Identificationproblemm
A large fraction of the asteroids observed so far are to be considered lost, that is they can not be recovered by pointing the telescope at the predicted position only. The catalogues of asteroid orbits are therefore polluted by large numbers of low accuracy orbits, which can not be easily improved by observation. Two of these inaccurate orbits can belong to the same physical object, and indeed...
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ژورنال
عنوان ژورنال: Science
سال: 2014
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.343.6171.580-c