7. DAY AND NIGHT…
But what is this motion we speak of?
It is the rotational movement of the earth , sun and moon
on its own axis as well as how the Earth revolve around
the sun while the moon also revolves around it.
8. All of these celestial bodies follow a common direction,
The sun rotates 27 earth days, and 225 million earth years
around the galaxy.
The Earth rotates onits axis for about 23 hours and 56 minutes and
makes a complete revolution for 365.3 days
Whereas the moon both rotates and revolves for about 28 days, making it
possible for the same portion of its surface to face the Earth all througout the
9. Another factor that affects the day and
night phenomenon is the eccentricity and
tilting of the Earth’s axis.
The deviation of the path of an orbiting
body from a true circle
A form of inclination due to
gravitational pull of the sun and other
11. Because of this eccentricity and tilting, it
causes different lengths of day and night
in different parts of the world.
13. Countries part of the Arctic Circle
19. Equinox literally means "equal
On the vernal (spring) and autumnal
(fall) equinoxes, day and night are
nearly the same length (the date on
which day and night are actually
closest to the same length is called the
equilux, and occurs a few days
towards the winter "side" of each
Neither hemisphere gets more
sunlight than the other, so both have
similar seasons (fall in one
hemisphere and spring in the other).
20. It came from the Latin word
“solstitium” meaning Sun and
“sistere” means stand still
The summer solstice, which happens
on June 21 or 22 each year, has the
longest daylight time. It's also the first
day of summer.
The winter solstice, on December 21
or 22, has the shortest daylight time,
and officially kicks off winter.
• Greenwich Meridian Time (GMT) refers
to the mean solar time at the Royal
Observatory in Greenwich, London,
which became adopted as a global time
• The International Date Line (IDL) is an
imaginary line on the surface of
the Earth that runs from the north to the
south pole and demarcates the change
of one calendar day to the next. It passes
through the middle of the Pacific Ocean,
roughly following the 180° longitude but
deviating to pass around some territories