Lecture 3 - Lecture3:MotionsoftheSunandMoon 91009 The 23.5...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 3: Motions of the Sun and Moon 9-10-09 The 23.5 degree tilt of Earth’s spin axis relative to its orbital axis around the Sun causes the seasons Celestial Coordinates The path of the Sun through the sky is called the Ecliptic Apparent Motion of the Sun The 23.5 degree tilt of Earth’s spin axis causes the Sun to move north and south across the Celestial Equator during the year Orbit of the Moon The Moon revolves around the Earth with a period of approximately one month It always keeps the same face pointed towards Earth This is a tidally locked orbit Motion of the Moon •The time between stellar alignments (the sidereal period of the lunar orbit) is 27.3 (solar) days, or one “Sidereal Month” •The time between Earth-Moon-Sun “alignments” is 29.5 (solar) days, or one “Synodic Month” Eclipses •Can occur only if the alignment is precise (Earth, Moon, and Sun line up exactly) •The Moon’s orbit is tilted by 5.2o relative to the ecliptic
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/28/2012 for the course ASTR 101 taught by Professor Becker during the Spring '12 term at Northern Virginia.

Page1 / 2

Lecture 3 - Lecture3:MotionsoftheSunandMoon 91009 The 23.5...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online