Why are shadows sharper in direct sunlight?

Answer: The sun acts like a point light source because it is so far away

UV rays make shadow edges look sharper — Wrong. UV light doesn't create sharp shadow edges; sharpness comes from the sun's rays arriving nearly parallel because it is so far away.

The Earth's distance from the sun makes light rays sharper — Wrong. Distance alone doesn't sharpen light rays; it's the sun's huge distance that makes its rays nearly parallel, which sharpens shadows.

The sun acts like a point light source because it is so far away ✓ — Correct! The sun is about 150 million km away, so its light reaches Earth nearly parallel—effectively a point source. This creates sharp shadows with a small penumbra (fuzzy edge). Nearby bulbs have diverging rays, making a large penumbra and softer shadows.