Question

Why is time frozen from light's perspective?​

Answer 1

Time is not frozen from light's perspective, because light does not have a perspective. There is no valid reference frame in which light is at rest. This statement is not a minor issue that can be approximated away or overcome by a different choice of words.

Answer 2

Hot air rises because when you heat air (or any other gas for that matter), it expands. When the air expands, it becomes less dense than the air around it. The less dense hot air then floats in the more dense cold air much like wood floats on water because wood is less dense than water.