Astro 100 MW


 

         

          Astro 100 MW

             The Solar System

             IUPUI (Daytime MW)

                     

                    Brian Woodahl

                    bwoodahl@iupui.edu

                    (Don't Use Canvas to contact me, use email link)

                    Office: LD 156-S, 278-9244

                    Class: IT 163 on Mon 11:30 - 1:10 and IT 157 on Wed 12:20 - 1:10

                    http://woodahl.physics.iupui.edu/Astro100MW

                    Is the University open/closed today?



Friendly Reminder: Exam 3 (Final) on Monday, April 30th


Exam 3 Study Guide


Quiz 12 (Wednesday, April 25)


Week 15 Images


Quiz 11 (Wednesday, April 18)


Week 14 Images


Quiz 10 (Wednesday, April 11)


Week 13 Images


Final Exam (Exam 3) Date


Quiz 9 (Wednesday, April 4)


Week 12 Images


Exam 2 Scores


Computing Your Current Grade


Week 11 Images


Exam 2 (Monday, March 26)


Exam 2 Study Guide


Quiz 8 (Wednesday, March 21)


Week 10 Images


Quiz 7 (Wednesday, March 7)


Week 9 Images


Quiz 6 (Wednesday, February 28)


Week 8 Images


Quiz 5 (Wednesday, February 21)


Week 7 Images


Exam 1 Scores


Computing Your Current Grade


Week 6 Images


Exam 1 (Monday, February 12)


Exam 1 Study Guide


Quiz 4 (Wednesday, February 7)


Week 5 Images


Quiz 3 (Wednesday, January 31)


Week 4 Images


Quiz 2 (Wednesday, January 24)


Week 3 Images


Quiz 1 (Wednesday, January 17)


Week 2 Images


Week 1 Images


Course Information


The Most Commonly Asked Question in Astronomy

A solar eclipse only occurs if the New Moon is about within half a degree of the ecliptic plane (defined by the orbit path of Earth as it travels around the Sun). The Moon's orbital path, around the Earth, is (unfortunately) inclined by about 5 degrees to the ecliptic. Thus, there are only two opportunities each moonth (punning) when the Moon passes through the ecliptic. These points are called the nodes (ascending, descending). The Moon passing through a node is not sufficient, it must pass through the node during the New Moon lunar phase.

About twice a year, during an approximately 45 day window (based upon the orbital speeds of the Earth and Moon), the New Moon is close enough to a node that a solar eclipse can occur. Further complicating the motion, the Moon's orbital plane precesses relative to the ecliptic. Hence, the nodes precess around the ecliptic, completing one rotation about every 18.6 years. In addition, because the Moon's path around Earth is elliptical, during many solar eclipses the angular diameter of the Moon is not large enough to fully cover the Sun. Only when the New Moon is near a node and near perigee (i.e. closest to the Earth), does totality occur. On average, it takes about 400 years for totality to occur again at the same geographical location.


Amazon.com Links for Textbooks (New and Used)


Excellent Beginner's Telescope for General Astronomy



Imagining the Tenth Dimension


Gravity Simulator


FYI (and Just For Fun)



Department of Physics, IUPUI - Updated on April 18, 2018 at 1:05 PM EDT