Without the atmosphere, there would be no refraction or scattering, and the Sun would rise later and set earlier than it now does.

Question

Quizplus · Accepted Answer

The atmosphere causes refraction and scattering of sunlight, which bends the light over the horizon, allowing us to see the Sun before it has actually risen and after it has set, thus extending daylight hours. Without the atmosphere, this bending would not occur, making sunrise and sunset more abrupt.

Without the Atmosphere, There Would Be No Refraction or Scattering