Kat asked in 科學天文與太空 · 1 decade ago

為什麼人造衛星的軌道大部分都是橢圓形

為什麼人造衛星的軌道大部分都是橢圓形

還有其他的行星的軌道也是橢圓形的

這是為神麼呢????

請給我整個的解釋

越多越好

謝謝

如果有英文網站的話更好

3 Answers

Rating
  • 1 decade ago
    Favorite Answer

    行星、人造衛星在太空中運行 (或說飛行),依靠的唯一力量是重力。

    而要維持圓形的軌道運行,我們需要一個固定大小的力量,也就是說,圓形軌道的向心力在軌道上的任何一處是定值。

    但是現實中,一個行星或人造衛星在軌道上的任何相異兩點所受的力都不會固定,因為萬有引力是彼此交相影響的,例如九大行星彼此會以自身的質量互相影響彼此所受的外力 (即太陽重力加上其他星球間的重力),進而影響到彼此的繞日軌道;因此,軌道上的各處受力不盡相同,就會變成橢圓形。

    在受力較大的地方,物體軌道就會比較靠近重力源,但是為什麼不落入重力源,是因為軌道速率在此時也最大的關係。(軌道速度和向心力方向垂直)

    REF:

    http://cse.ssl.berkeley.edu/bmendez/ay10/2002/note...

    http://www.fourmilab.ch/gravitation/orbits/

  • Anonymous
    6 years ago

    到下面的網址看看吧

    ▶▶http://qaz331.pixnet.net/blog

  • 宗慶
    Lv 6
    1 decade ago

    一、人造衛星採用橢圓形軌道之理由:

    Depending on the mission objectives. For example, most earth-observing

    s orbits are nearly circular in order to maintain (nearly) constant altitude and speed to get better image quality (uniform pixel distribution,... etc). For geosynchronous satellites, the orbit must be circular for the satellite to stay "fixed" with respect to the earth. One example of non-circular orbit is the "Molniya" orbit which is elliptical (period: 11.967 hours, eccentricity about 0.7). The purpose is for the satellite to stay as long as possible above the high latitude area (e.g. Russia) for communications.

    二、人造衛星採用橢圓形軌道之原理:

    Please look at the detailed proof of Kepler's laws. The files are now in the attachment of this Email. Generally speaking, the orbit MUST BE elliptical for the satellite to maintain stable and periodical motion.

    Orbital Motion and Kepler's Laws

    http://school-for-champions.com/science/orbit.htm

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