What causes sunlight to be redirected toward an observer's eye on Earth, but not in space?

Answer

The gas molecules in the atmosphere act as a scattering and diffusing medium

On Earth, gas molecules scatter sunlight in every direction, diffusing the light. In space, the vacuum lacks this scattering medium, so light travels directly from the source without redirection to the eye from other angles.

What causes sunlight to be redirected toward an observer's eye on Earth, but not in space?
Spaceskyastronautsvacuumlight scattering