Origins of the zodiacal dust cloud

摘要: The total intensity of light scattered by interplanetary dust has usually been directly related to the mass lost because Poynting-Robertson effect. thus would appear define a supply rate that must be maintained if is remain constant. This work suggests comets apparently cannot this quantity cloud, radiative pressures prevent most comet debris and its secondary collision fragments from entering closed orbits about sun. More observations on actual emission rates very-short-period may needed before can conclusively established. It shown asteroidal collisions provide sufficient debris, but injection extremely variable produced in very rare between largest asteroids. concluded no current theory capable accounting for steady cloud. A possible solution might found processes counter drag permit grains long lived. present then adequate account stationary An alternative highly with collisions. epoch have one unusually high density.