The Meaning of "The Shadow at the Time of the Sun's Decline" in the Time of the Dhuhr Prayer

Question:
He says: Honorable Shaykh, may Allah grant you success. He says: In the time of the Dhuhr prayer, the time for Dhuhr extends until the shadow of every object becomes equal to its length after the shadow at the time of the sun's decline. What is meant by "the shadow at the time of the sun's decline"?

Answer:
The shadow at the time of the sun's decline is the shadow at which the sun declines, because the shadow does not shrink completely, as the sun tilts toward the north in the summer and toward the south in the winter. So there is a shadow; this is called the shadow at the time of the sun's decline.