Tidal deformations and the origin of the moon

Abstract

Results of a provisional survey of the ellipticities of lunar possible modes of origin of the moon are discussed. If the pre-mare craters in selected areas of Kuiper's Atlas are discussed. The rms craters mark the end of a continuous process of accretion which random ellipticity is found to be 0.070 near the center, 0.096 built the moon, the observed small systematic deformations of the near the limb, and is probably due to oblique impact. Small craters are only compatible with the moon having accreted from preferential components of ellipticity are indicated and inter- a cloud of fragments circling the earth in direct orbits at a distance preted as possible after-effects of past tidal deformations. For- of five to eight earth radii or greater. The assumption of different mulae for tidal-rotational deformations of line elements on an processes for accretion of the moon and for the formation of pre- elastic nonresisting surface are given. The smallness of the mare craters leads to improbable consequences. Only when the preferential effects is in itself significant, without regard to their preferential ellipticities are discounted as due to other causes or to absolute value. They suggest that the craters were formed when chance, is it possible to accept the alternative of the moon having the earth-moon distance was of the order of 30 000 km. accreted from interplanetary material orbiting the sun. Accretion The undamaged appearance of the craters except for impact must then have run simultaneously with tidal evolution following erosion and flooding, and the absence of signs of major crustal initial tidal capture, the pre-mare craters having formed at a deformations indicates that since crater formation the moon distance of over 200 000 km from earth as the final stage of this could not have been at a closer distance. From theoretical rates accretion. of accretion as based on probabilities of interplanetary collisions,