Without knowing it most of us stay up longer because the day is .... longer than what it is supposed to be, blame it on the phenomenon of atmospheric refraction and angle of the Sun. This animated physics topic gives in-depth information to high school and college students about how atmospheric refraction works.
than actual : This animation contains the following
Does the sun rises earlier or sets later than it seems
Explanatory Notes section contains :
What is refraction ?
Why density of air is maximum at earth's surface and decreases
as we go higher?
Sun rises earlier than its actual
Sun sets later than its actual time
This is due to the phenomenon of
atmospheric refraction that we have a longer than
Details of the animation/ movie /software
This is a natural phenomena due
to atmospheric refraction.
On the earth's surface, density of air is maximum, and as
we go higher, the density of air becomes Lesser. The ray
from the Sun when enters into the atmosphere of earth travels
from Rarer to Denser media and bend towards the normal.
But our eye can follow only the straight line path.Thus
sun appears to be above the horizon when it is actually
below the horizon. So the Sun appears to rise earlier than
its actual time.
The same things happen in the time of sunset .So the Sun
sets later than its actual time.
As a result of these two phenomena we get more time in