The reasons why day and night occurs

1. OUR
MOTHER
EARTH
LET’S
unravel
some of
its
mysteries
IN
321

3. DAY AND NIGHT…
What does it have to do with
planet earth?

4. DAY AND NIGHT…
It is a phenomenon that occurs in
accordance to the motion of the EARTH
and its relation to the SUN and MOON.

5. Similar to this video clip…

6. But the reality is….

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,
travelling counter-clockwise.
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
year.

9. Another factor that affects the day and
night phenomenon is the eccentricity and
tilting of the Earth’s axis.
Next

10. ECCENTRICITY
The deviation of the path of an orbiting
body from a true circle
TILT (Obliquity)
A form of inclination due to
gravitational pull of the sun and other
planets.
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k

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
 United
States
(Alaska)
 Canada
 Greenland
 Norway
 Sweden
 Finland
 Russia

14. Countries part of the Tropic of Cancer,
Equator and Tropic of Capricorn

15. Countries part of the Arctic Circle

17. In order to better understand this
discrepancies, we must first tackle about
the equinox and solstice.

18. PerihilionAphelion

19.  Equinox literally means "equal
night".
 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
equinox).
 Neither hemisphere gets more
sunlight than the other, so both have
similar seasons (fall in one
hemisphere and spring in the other).
EQUINOX nex
t

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.
Solstice

21. TIME
• Greenwich Meridian Time (GMT) refers
to the mean solar time at the Royal
Observatory in Greenwich, London,
which became adopted as a global time
standard.
• 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

22. TIME

23. THANK YOU FOR
LISTENING!!
Made by: Elaine B. Espejon