If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet?

the planet rotates on its own axis

Explanation:

The planet rotates on its own axis. The planet is rotating to cause day and night. All planets rotate on the principle of angular momentum. No force is required for the planets to rotate. The rotation results in the centrifugal acceleration that points towards the center of the object. The rotation also causes day and night. For all planets, the time period of the day and night varies. The planet nearest to the sun has a longer rotational time period and the planet far away from the sun has a shorter rotational time period. For example, mercury completes one rotation in 88 days and Neptune complete single rotation in 16 hours