萬(wàn)有引力控制著天體的運(yùn)動(dòng)。Gravity governs the motions of celestial bodies.觀測(cè)者必須具備一份包括肉眼能看到的所有天體的好星圖.Indispensable for the observer is a good star atlas, containing all naked eye stars.構(gòu)成這些天體的每一種化學(xué)元素都會(huì)以它們特有的波長(zhǎng)發(fā)出輻射.Each of the chemical...