1. RELATIONSHIP OF THE SUN TO THE
EARTH
Presented by : Mr T Mokgopa
: 074 848 1524
: tsiamo.mokgopa21@gmail.com
2. THE SOLAR SYSTEM, SUN, AND EARTH
• Our Solar System is found on the Milky Way Galaxy.
• Our Solar System is embedded on the Orion Spur of the Sagittarius Arm.
• Dust and gas, a nebula are believed to have formed our Solar System.
• The Earth is approximately 150 million km away from the Sun. Thus, light reaches Earth from the
Sun in an average of 8 min and 20 sec.
• Aphelion : Earth’s farthest position from the Sun.
• Perihelion : Earth’s closest position to the Sun.
3. THE MILKY WAY GALAXY
(Christopherson, R. W. & Birkland, G. N., 2015)
4. SOLAR ENERGY: FROM SUN TO EARTH
• 99.9% of the matter from the solar nebular was captured by the Sun, while the
remaining 0.1% formed all the planets, asteroids, comets, satellites and debris.
• Radiant energy : energy of electromagnetic waves which can travel through.
• Fusion : the forcing of Sun’s abundant hydrogen atoms together and joining pairs
of hydrogen nuclei.
5. UNEVEN DISTRIBUTION OF INCOMING SOLAR
RADIATION (INSOLATION)
(Christopherson, R. W. & Birkland, G. N., 2015)
6. THE SEASONS AND SEASONALITY
At sunrise or sunset, the Sun is at the horizon, at 0° altitude.
The Sun is at 45° altitude during the day when it reaches halfway between
the horizon and directly overhead.
The Sun is directly overhead, at 90 ° altitude where insolation is at its
maximum. This is the subsolar point.
7. REASONS FOR SEASONS
• Revolution
• Rotation
• Tilt of Earth’s Axis
• Axial Parallelism
• Sphericity
• NB: Video Link of the Revolution and Rotation of the Earth:
https://youtu.be/l64YwNl1wr0
8. 1. REVOLUTION
• The Earth orbits the Sun in an average speed of 107, 280 kmph.
• The Earth completes its annual revolution about the Sun in 365.2422 days (Full
year).
• The number of days are based on the TROPICAL YEAR which is measured from
Equinox to Equinox, or the time elapsed between two crossings of the equator by
the Sun.
9. THE REVOLUTION OF THE EARTH
(Christopherson, R. W. & Birkland, G. N., 2015)
10. 2. ROTATION
• Earth rotates on its axis in a complex motion that slightly has an average less that 24 hours in duration.
• The Daylength is determined by the rotation of the Earth.
• When observed from above the North Pole, Earth rotates in a counter-clockwise direction on its axis.
• An Axis is an imaginary line that that extends through the planet from the North Pole to the South Pole.
• When viewed from the equator, Earth rotates in an Eastward direction which creates the Sun’s apparent
westward daily journey which supports the Sun rising in the East and setting in the West.
• The linear velocity of rotation varies at different points on Earth even though one full rotation takes 24
hours.
• Earth produces the diurnal pattern of day and night. This results in the creation of a circle of
illumination which is a line dividing day and night.
11. 3. TILT OF THE EARTH
• For Axial Tilt (Tilt of the Earth), imagine a flat surface that intersects the elliptical orbit of the
Earth about the Sun, with half of the Earth and Sun above the surface and the other below. This flat
surface touching all points of the orbit of the Earth is referred to as the plane of ecliptic.
• As Earth revolves around the Sun, the Earth’s tilted axis remains fixed relative to the plane of
ecliptic.
• Now imagine a perpendicular line passing through the plane. From this perpendicular line, the
Earth is tilted at about 23.5°, forming an angle of 66.5° from the plane itself. This thus results in
different poles of the Earth receiving Sunlight at different times.
12. THE TILT OF THE EARTH (AXIAL TILT)
(Christopherson, R. W. & Birkland, G. N., 2015)
13. 4. AXIAL PARELLELISM
• In its annual journey of revolving around the Sun, the axis of the Earth maintains
the same alignment in relation to the plane of ecliptic.
• The comparing of the axis in different months would always show it being
parallel to itself.
• This condition is referred to as Axial Parallelism.
14. 5. SPHERICITY
• Even though the Earth is not a perfect sphere, it is still referred to and considered a
sphere.
• The Earth’s Sphericity contributes to the change in Seasons.
• The sphericity of the Earth results in the uneven distribution of the Sun’s heat on
the Earth’s surface.
• This uneven distribution of heat is also apparent in Slide 5 of this presentation.
16. LIST OF SOURCES
• Aaurorap. (2013). Uneven Distribution of Solar Energy. Available from Slideshare at
https://www.slideshare.net/aaurorap/uneven-distributionofsolarenergy-15893258 (Accessed 20 August 2021)
• Christopherson, R. W. & Birkeland, G. N. (2015). Insolation receipts and Earth’s curved surface [Photography]. An
introduction to Physical Geography: Geosystems textbook.
• Christopherson, R. W. & Birkeland, G. N. (2015). Earth’s revolution and rotation [Photograph]. An introduction to Physical
Geography: Geosystems textbook.
• Christopherson, R. W. & Birkeland, G. N. (2015). The plane of the Earth’s orbit [Photography]. ]. An introduction to
Physical Geography: Geosystems textbook.
17. LIST OF SOURCES CONTINUED
• iCareNOW, a service of The Myrtun Corporation. (2011). The Milky Way Galaxy. Available from Slideshare at
https://www.slideshare.net/iCareNOW/the-milky-way-9883249 (Accessed 18 August 2021)
• Ischmidt1170. (2010). Earth and sun relationships. Available from Slideshare at
https://www.slideshare.net/lschmidt1170/earth-and-sun-relationships (Accessed 20 August 2021).
• Kirkham, S. (2009). Earth Sun. Available from Slideshare at https://www.slideshare.net/wskirkham/earth-sun (Accessed 21
August 2021)
• Ulster, S. (2011). 5 earth movements and seasons. Available from Slideshare at
https://www.slideshare.net/SUNYUlsterInstructs/5-earth-movements-and-seasons (Accessed 23 August 2021)