Oh, now THIS will make your head really thump.

Quote Originally Posted by ggiese View Post
Ooohh... I dunno Kris. A popular misconception.

I know it's rhetorical, but formally the angular momentum of a point object is defined as the cross product of the object's position vector (a measure of an object's resistance to changes in its rotation rate) and the linear momentum vector. By that definition, angular momentum cannot possibly be the same as linear momentum.
Ah yes, I can see that. However there will be both a slowing of momentum from friction and curvature of the linear path due to gravity.

For example, a projectile (arrows, bullets, artillery shells, etc.) will eventually slow down from atmospheric friction which allows gravity to alter the projectiles course. This arguement can also be used for light, since light waves can be altered by gravity (red shift) and be effected by interstellar dust or other celestial bodies that the light would have to pass through.