# Does the conservation of angular momentum depends upon the choice of point about which you are calculating it?

I know that torque is the rate of change of angular momentum.

Suppose a planet is revolving around the sun. Then its angular momentum about the common center of mass of the planet and the sun will remain conserved, as the external torque acting on the planet is zero.

However, if we consider the angular momentum of the planet about a point present on its orbit, the angular momentum of the planet will not remain conserved. For example when the planet is on the point itself, at that instant position vector is zero so angular momentum of planet is zero. But as planet progresses on its orbit angular momentum will now be non zero. This implies that there must be an external torque acting on the planet.

Therefore, the conservation of angular momentum in this case depends on the choice of the point about which we are calculating the angular momentum.

Am I interpreting the things correctly or not? Please help me understand.