34
5.
THE EARTH’S MOVEMENTS
The Earth, like the rest of the planets in the Solar System, moves around the Sun. It
also moves on its own axis.
5.1.
The Earth’s revolution
The Sun is not located in the middle of ellipse because the distance between the
Earth and the Sun varies as it moves along its orbit.
❚
The
maximum distance
of the Earth from the Sun is 152 million km, reached in
the summer in the Northern Hemisphere.
❚
The
minimum distance
of the Earth from the Sun is 147 million km, reached in
the winter.
Because takes a little more than 365 days to complete its revolution (almost a
quarter of a day more), we have to add a day to the month of February every 4
years. This is called a
leap year
.
The Earth’s revolution has some characteristics that permit light and temperature
conditions that are ideal for life to exist.
The Earth moves around the sun in an elliptical orbit. It takes the Earth 365
days, 5 hours and 49 minutes to complete one
revolution
.
Inclination of the terrestrial axis and translation movement
Analyse
20.
Discuss where the highest temperature would be: at the point where
the Sun’s rays hit the Earth directly, or at the point where they hit at an
angle.
The Earth is
tilted
6
23.5º
perpendicular to the ecliptic plane.
As it moves, the Earth keeps its
tilt
7
.
The Earth moves around the Sun
on a plane called the
ecliptic
plane
.
Because the Earth is
almost
spherical
, the Sun’s rays don’t hit
all parts of the planet at the same
angle.
This angle varies depending on the
Earth’s position with relation to
the Sun.
7
Analyse
19.
Can you explain why, if
the Earth moves, we don’t
feel the movement?
7
6
tilt
(v)
:
incline
7
tilt
(n)
:
angle between a planet’s
axis and its orbital plane
