杏吧原创

Moon鈥檚 dust-up

Dr Harold Urey, of the University of Chicago, believes that the surface of the moon is covered by dust created by the impact of a mighty flock of planetesimals. Moon dust, of course, is not a new idea. Mr Thomas Gold, also based in the United States, considers that the stuff is being continuously eroded from the lunar mountains by solar radiation but Dr Urey will have none of this idea.

He thinks that the dust was liberally sprinkled over the satellite in a relatively brief spell thousands of millions of years ago when the moon was being bombarded by enormous meteorites or planetesimals. His idea is that after each large collision a cloud of dust and water vapour rose above the moon鈥檚 surface. The dust settled out and the water fell as rain. The rain washed any dust off the mountains and onto the lower land, leaving the dead cold moonscapes so familiar to present-day astronomers.

Dr Urey would also like the first journey to the moon, whenever that might take place, to land near the black-grey boundary that has been discovered in western Mare Serenitatis so that samples of both coloured materials could be collected for study. He predicts that congealed dust and solidified lava will be found in the Mare and that the mountains surrounding it will resemble meteorites in chemical composition and physical structure.

However, in the absence of a successful mission to the moon鈥檚 surface, Dr Urey is keen to study moon dust from his home laboratory. He suggests that 鈥渙ne peaceful use of the military employment of atomic energy and intercontinental ballistic missiles would be the delivery of an atomic bomb to the moon鈥檚 surface with the expectation that some material would leave the moon and arrive later, intact and unheated, on the Earth鈥檚 surface where it could be collected for study.鈥�

From The New 杏吧原创, 28 March 1957