Physics 320
Astrophysics I:  Lecture #4 HW Problem
Prof. Dale E. Gary

Elliptical Orbit of Mercury

Prob. 2A: (a) In Lecture 4, we gave the following information from 2001-2002. Repeat this exercise for 2017-2018, using the JPL Calendar to look up the greatest elongations, and create an accurate sketch of Mercury's orbit. Assume Earth's orbit is circular (not precisely correct, but close).

(b) Measure the semi-major and semi-minor axes as accurately as you can directly from your sketch, and calculate the eccentricity of Mercury's orbit. Compare with the accepted value.

Information repeated from Lecture 4 (you'll replace the table with the 2016-2017 information): Greatest Elongations for Mercury in 2001-2002   (from JPL Calendar)

Animation showing the six consecutive greatest elongations of Mercury listed above.  The position of Earth is advanced the appropriate number of degrees around its orbit for each date, then the line to Mercury is drawn East or West of the Sun as needed.  Mercury is on this ray, at the point that the ray passes closest to the Sun.