PSunit3notes
- 1. Basic Definitions: Ecliptic Ecliptic - Plane of Earthʼs orbit around the sun. Sometimes also called Ecliptic Plane. 7
- 2. Basic Definitions: Inclination 8 Inclination - Angle between ecliptic and plane of planet (or satellite’s) orbit.
- 3. 9 Inclinations of Planets in the Inner Solar System
- 4. All Planets Are Near the Ecliptic 10 Eris Pluto Ceres
- 5. 11 Saturn Ecliptic From Earthʼs Surface Venus Jupiter Mercury
- 6. Ecliptic From the Far Side of Moon 12
- 7. Basic Definitions: Obliquity 14 Obliquity - Tilt of planetʼs spin axis relative to plane of its orbit around the sun.
- 8. Obliquity of the Planets 17 Earthʼs obliquity is 23.5°
- 9. Obliquity of Other Planets 18 Mercury - 0.1° Venus - 177° Earth - 23° Mars - 25° Jupiter - 3° Saturn - 27° Uranus - 98° Neptune - 30°
- 10. Common Misconceptions about Seasons #1) Many people think seasons on Earth are caused by the change in the distance of Earth from the Sun. In fact, Earth is closer to the sun in January than in July (by about 5 million km). 21
- 11. Earth’s Obliquity Causes Seasons • Affects the length of day and angle of sunlight. 23 June 21 Sept 22 Dec 21 March 20
- 12. 25 Northern Summer Solstice Longest Day
- 13. 28 The Equinoxes 12 Hour Day
- 14. Northern Winter Solstice 29 Shortest Day
- 15. Angle of Sunlight Striking Earth Angle depends on latitude and time of year 32
- 16. Angle of Sunlight Striking Earth Angle depends on latitude and time of year 33
- 17. Earth’s Obliquity Causes Seasons When northern hemisphere is tilted away from the sun the resulting shorter days (longer nights) and greater angle of sunlight lead to cooler temperatures (winter). 35
- 18. THE END 36 Precession - The natural tendency of all rotating objects to wobble. The rotational axis of the Earth, and all planets, constantly wobbles. For the Earth, one full precession takes approximately 26,000 years.