Question

Why can we see the sun 2 minutes before the actual sunrise and 2 minutes after the actual sunset?

Answer 1

It is actually the phenomenon of advance sunrise and delayed sunset. The sun appears to rise two minutes before the actual sunrise and set two minutes after the sunset due to . By actual sunrise, it meant that actual crossing of the horizon by the sun. This makes us think that the light is coming straight from the Sun.

Answer 2

The Sun is visible to us about 2 minutes before the actual sunrise, and about 2 minutes after the actual sunset because of atmospheric refraction. By actual sunrise, we mean the actual crossing of the horizon by the Sun. The apparent flattening of the Sun's disc at sunrise and sunset is also due to the same phenomenon.