Here's why:

* Solar Noon: This is the moment when the sun reaches its highest point in the sky for a particular location on a given day.

* Angle of the Sun: At solar noon, the sun's rays are hitting the earth at the most direct angle, causing the shortest possible shadow.

Important Note: Solar noon is not necessarily the same as 12:00 PM on your clock. The exact time of solar noon varies depending on your location and the time of year.