Earth and the Sun

1. Earth and the Sun Earth Science 2013

2. Astronomy Astronomy • Definition: The study of the planets,[------ moon, stars, and other objects in space

3. Sun The Sun • The Sun is the center of our Solar System • There are 8 planets in our solar system • We are 92 million miles from the Sun • The Sun is responsible for all the energy we receive on Earth

4. Earth • The planet we live on • Only Planet with life(that we know of…) • Third planet from the Sun

5. Earth • The Earth is an inner planet • Small in size • Few or no moons(only one) • No rings

6. Earth’s Movements • Rotation: One spin on its axis • Takes about 24 hours to rotate once • This rotation causes DAY and NIGHT • Sun always rises in the EAST and sets in the WEST

7. Earth’s Movements • Revolution (orbit): One lap around the Sun • This takes about 365 days or one year to complete • The path is not quite a circle; its more of an oval shape

8. Calendars • Calendars mark time on earth in 24 hour days and 365 days per year • The Egyptian astronomers counted the days between the appearance of the star Sirius and found an average of 365 days between appearances. • So the Egyptians came up with one of the first Calendars!

9. Leap Years • The path of the Earth around the Sun actually takes 365 ¼ day to complete. • Every fourth year we add up the extra time ¼ + ¼ + ¼ + ¼ = one extra day • This day is added to the calendar every 4 years on February 29 • Leap Years: 2004, 2008, 2012, 2016, 2020, 2024, 2028, etc

10. Earth’s Tilt • Earth has seasons because the axis is tilted as it moves around the Sun • WE ARE IN THE NORTHERN HEMISPHERE • When the Northern Hemisphere is tilted towards the Sun, we get the most sunlight = summer • When the Northern hemisphere is tilted away from the Sun, we get the least sunlight = winter

11. Seasons

12. Seasons • Most places on Earth have 4 distinct seasons: Winter, Spring, Summer, and Fall • The length of each season depends on its location on the Earth and how the sunlight hits the Earth • The uneven heating of the Earth creates three different climates: tropical, temperate, and polar

13. Season’s interactive • Click here

14. Four Seasons • Winter Solstice • Starts around December 21 • Northern Hemisphere is tilted away from the Sun • The rays from the Sun are the weakest • Shortest day of the year in Northern Hemisphere; longest day of the year in the Southern Hemisphere • Marks the beginning of winter

15. Four Seasons Four Seasons • Autumnal Equinox • Starts around September 22 • The Suns is directly over the equator creating an equal amount of daytime and nighttime • Marks the beginning of Fall

16. Four Seasons • Spring Equinox • Starts around March 21 • The Suns is directly over the equator creating an equal amount of daytime and nighttime • Marks the beginning of summer

17. Four Seasons Four Seasons • Summer Solstice • Starts around June 21 • Northern Hemisphere is tilted towards the Sun • The rays from the Sun are the strongest • Longest day of the year in Northern Hemisphere; shortest day of the year in the Southern Hemisphere • Marks the beginning of the summer

18. Climate Zones

19. The Moon • The Moon takes 27.3 days to revolve around the Earth • The Moon takes 27.3 days to rotate on its axis • Therefore, we only ever see one side of the moon

20. Lunar Landing Sites