1-11-2008 Lecture 4 - Precession of the Equinoxes The...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Annual Motion Ecliptic – The apparent path of the Sun through the sky Equinox – When the Sun on the ecliptic intersects or is at the celestial equator Solstice – Where the Sun on the ecliptic is farthest from the celestial equator Zodiac – The constellations which lie along the ecliptic Seasons are caused by the Earth’s axis tilt. Summer: The solstice (~June 21) is considered the first day of Summer. It takes time for the more direct sunlight to heat up land and water. July and August are usually hotter than June. Distance does not matter in 4 seasons due to small variation for Earth – about 3%. Seasons are more extreme in North, because water takes longer to heat and cool than land. Water has a temperature regulating effect, as there is less water in Northern Hemisphere, the weather is more extreme.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Precession of the Equinoxes The Earths axis precesses like a top, once about every 26000 years. Precession changes the positions in the sky of the celestial poles and the equinoxes Polaris wont always be the North Star. Lunar Motion We always see the same face of moon because rotation period = orbital period. Eclipses Moons orbit tilted 5 to ecliptic plane.-Crosses ecliptic plane only at the two nodes.-Eclipse possible only when full/new occur near nodes.-Orbit tilt must be in position where the orbit passes in front or back of Earth at new/full moon. Moons orbit intersects the ecliptic at new moon Solar eclipse Within umbra Total solar eclipse Within penumbra Partial solar eclipse at full moon Lunar eclipse...
View Full Document

Ask a homework question - tutors are online