For the minor planets, comets, and meteors whose orbital elements are known values of the dispersions σi(a) of the inclination i for intervals of the semimajor axis a have been calculated. Calculations on the minor planets show that, from the point of view of secular perturbations, σi(a) is more stable than ī(a), and we have therefore taken it as a fundamental relation for further considerations. It has been found that the relations σi(a) are linear for minor planets, comets, and meteors with a > 2 AU. The lines are parallel, and for a > 2 AU the σi(a) are proportional to a. Meteors have a second straight line for a < 2 AU, and in this case σi(a) is proportional to 1/a. It is concluded that minor planets, comets, and meteors could have a common origin.