Neutrinos and the hypothetical gravitons, also massless particles, move at the same speed as light . 中微子和假想的引力子也是无质量粒子，它们也以与光相同的速度运动。
In molecular terms, an ideal gas is a gas whose molecules exert no forces of attraction at all . 理想气体，用分子的术语来讲，是指该气体中的分子之间完全没有引力存在。
The gravitational attractions of the pieces of dust for one another might make them form little lumps . 尘埃片与片之间由引力而产生的吸引，可能会使它们形成一些小的团块。
When the separation of the molecules is large, as in a gas, the force is extremely small and attractive . 分子间的距离较大时，如在气体中，分子间的作用力极为微小，而且是引力。
The criterion for gravitational contraction set by equations (3. 4) is significantly weaker for more massive clouds . 由（34）式建立的引力收缩判据，对质量较大的云是很牵强的。
The idea of an inverse-square law of gravitational force acting on the planets was in the air around newton's time . 认为作用于行星的是平方反比定律的引力，这种看法在牛顿时代很流行。
The steady pull of the earth's gravity on one side of the moon has made this bulge slightly toward the earth . 地球引力长期作用于月球对着地球的那个面上，已经使得那面向着地球微微隆起。
The life history of any star truly represents a titanic struggle between the force of gravity, and the force of gas pressure . 任何恒星的生命史，就是一场引力和气体压力之间的严重斗争。
The spinar is a gigantic machine converting gravitational binding energy into electromagnetic radiation by means of rotation . 旋转体是一架通过自转把引力束缚能转换为电磁辐射的巨大机器。
