The sun doesn't actually appear bigger in the morning. It's an illusion created by our brains and the way we perceive the world.

Here's why it seems that way:

* Atmospheric Distortion: When the sun is near the horizon, its light has to travel through more of the Earth's atmosphere to reach our eyes. The atmosphere acts like a lens, bending the light and making the sun appear slightly larger and flatter.

* Relative Size: When the sun is low on the horizon, we see it against a background of trees, buildings, and other objects that provide a reference point for size. This makes the sun appear larger in comparison.

* The Ebbinghaus Illusion: This is a well-known psychological phenomenon where we perceive the size of an object differently depending on the size of the objects around it. When the sun is near the horizon, we're more likely to compare its size to other objects, making it seem bigger.

So, it's not that the sun actually grows larger in the morning, but rather that our perception of its size changes due to these factors. The sun remains the same size throughout the day.