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Seasons PowerPoint Presentation

Seasons

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Seasons

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  1. Seasons

  2. The Zodiac throughout the Year Example: In Winter sun in Sagittarius, Gemini at night sky;in summer sun in Gemini, Sagittarius at night sky

  3. The Seasons • Change of seasons is a result of the tilt of the Earth’s rotation axis with respect to the plane of the ecliptic • Sun, moon, planets run along the ecliptic

  4. Ecliptic horizontal, Celestial equator and Earth axis tilted

  5. Demos • TeacherTube video • Season apparatus • Wikipedia Icecover

  6. What changes? • Sun is closer to the celestial north pole in the northern summer • Therefore it is higher in the sky • Therefore the sunlight hits us more directly • Therefore the energy deposit per unit area is higher • Therefore the temperature goes up • Therefore the sun is above the horizon longer • Therefore there is more sunlight per day • Therefore the temperature goes up

  7. Illumination Angle and Energy density From Wikipedia

  8. What does not change • The direction of the Earth’s axis (still points to the CNP) • The distance to the sun (there is a 1.7% change of the distance to the Sun, but we get closest to the Sun in early January!) • The fact that we are about an Earth radius closer to the Sun at noon in the summer is negligible (6300km compared to 150 mill.km is 0.004%)