close-by orbit 中文意思是什麼
close-by orbit
解釋
鄰近軌道-
The asteroids are the most important small bodies in the solarsystem, and they mainly lies in the two locations - a main belt between the mars ' s orbit and the jupiter ' s and the near - earth space. the most feature of the orbits of near - earth asteroids ( neas ) is that the semi - major axes of the orbits are nearly equal to that of the earth or the perihelia distances are approximate to or even less than the mean distance between the sun and the earth, thus they could move into inside of the earth ' s orbit, so that they might close approach or even colliside with the earth ( or other planets, such as the venus, the mars, etc. ). the characteristic brings about some difficulties in the numerical research during their orbital evolution, which leads to the failure of the normalization technique in the general removal impact singularities of celestial mechanics methods and the symplectic algorithm which is successfully applied to the investigation in quality. by comparing the computation effects of several common numerical methods ( including symplectic algorithm ), and considering the nature of the movement of the small bodies, the corresponding treatments are provided here to improve the reliability of the computation
小行星是太陽系最重要的一類小天體，主要分佈在兩個區域；火星和木星軌道之間的一條主帶和近地空間.近地小行星軌道的最大特點是其軌道半長徑與地球軌道半長徑相近，或近日距離接近甚至小於日地平均距離，其運動可深入到地球軌道的內部，這將導致該類小行星與地球（還有金星、火星等）十分靠近甚至發生碰撞.這一特徵給其軌道演化數值研究帶來一些困難，包括天體力學方法中一般消除碰撞奇點的正規化處理以及對定性研究十分成功的辛演算法都將在不同程度上失效.通過對幾種常用數值方法（包括辛演算法）計算效果的比較，根據小天體運動自身的特性，給出了相應處理措施，從而可提高計算結果的可靠性 -
Some asteroids, despite their small size, possess satellites of their own. a handful of others suffer serious perturbations by major planets and travel in highly eccentric orbits, which can send them well beyond the orbit of jupiter. the so - called near - earth asteroids cross the earth s orbit and make occasional close calls to our home planet
有些小行星體積雖小，但竟然擁有衛星而有些小行星，由於受到其他大行星的強烈攝動，軌道為極狹長的橢圓，遠日點甚至延伸至木星的軌道以外近地小行星則會越過地球的軌道，不時在我們的庭園掠過，偷窺地球的一切，若有天真的登門造訪旄轟！
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