地球扁率在地质历史上的变化下限

摘要

为研究地球形状的长期变化,将地球假设为弹性椭球体,根据弹性动力学理论导出地球的扁率下限公式,扁率与地球的平均密度ρ、引力加速度g、自转角速度ω、平均半径R、弹性模量E、泊松比7相关.将新星云假说下地质历史时期半径、质量和角速度变化值代入公式计算出各地质历史时期地球扁率值,作为地球扁率变化值的下限值.地球的扁率自地球形成以来总体变化趋势是在减小.%A variation in the earth' s shape is one of the basic problems of earth evolution. A variation in the earth's oblateness can be used to understand the variation of the earth's shape. Assuming the Earth is flexible ellipsoid, according to the theory of elastic dynamics, we derived the formula for minimum oblateness of the Earth and conclude that oblateness of the Earth is a function of the average density of the Earth p, the gravitational acceleration g, rotation rate w, average radius R, elastic modulus E and Poisson's ratio v. Apply parameters such as the radius, mass, and the change in angular velocity of the Earth, which are based on the new nebular hypothesis, into the formula to calculate the lower limit of oblateness of the Earth in different geological epoch. The oblateness of the Earth has signs of reduction in its magnitude since the formation of the Earth.