Disclaimer: The following material is being kept online for archival purposes.

Although accurate at the time of publication, it is no longer being updated. The page may contain broken links or outdated information, and parts may not function in current web browsers.

Site Map

Kepler's Laws

Sections involving Kepler's Laws in "From Stargazers to Starships"

    The following 7 sections discuss Kepler's laws and develop some applications. Includes equations and properties of conic sections, the derivation of the scale of the solar system (absolute distances, not relative ones), the energy equation for Keplerian motion and the reason why spring and fall equinox are not exactly half a year apart.

    Section 12b goes into some details of interest to those who wish to study more of celestial mechanics, , e.g how the "mean anomaly" (briefly defined in sect. 12) is actually derived, and how the orbit is defined in three dimensions.

    This discussion continues in section #20 on Newton's "Universal Gravitation" and the two that follow, in which Kepler's 3rd law is derived for circular orbits.

    In section #21b Kepler's 3rd law is used to calculate (approximately) the time needed for a spaceship to fly from Earth to Mars.

    Lesson plans for teachers exist for most of these sections, starting with http://www.phy6.org/stargaze/Lkeplaws.htm and continuing in sections 11, 12, 11a, 12, 20 and 21 of http://www.phy6.org/Lintro.htm

Back to the Home Page

Author and Curator:   Dr. David P. Stern
     Mail to Dr.Stern:   stargaze("at" symbol)phy6.org .

Last updated: 18 September 2004

Above is background material for archival reference only.

NASA Logo, National Aeronautics and Space Administration
NASA Official: Adam Szabo

Curators: Robert Candey, Alex Young, Tamara Kovalick

NASA Privacy, Security, Notices