Kepler's Work Today
by ali-wa

Johannes Kepler, 1571-1630 (public domain)

Kepler's work back in the 16th and 17th centuries was revolutionary. It changed the way we saw the universe, and it laid the groundwork for many later scientific discoveries. For example:
  • A book Kepler published in 1601 refuted the accuracy of astrology and established astronomy as the true science of the stars (Lamont, 1992). Because of that, we now regard astronomy as a science and dismiss astrology as superstition.
  • Because of his Laws of Planetary Motion, we now know that planets’ orbits are elliptical (not circular, as was believed before Kepler), that planets do not orbit at a constant speed but rather speed up when they are closer to the sun, and that planets closer to the sun orbit at a faster rate than those farther from the sun.
    • This has enabled us to create accurate models of the solar system and made all our extraterrestrial voyages possible.
  • Kepler’s work laid the foundations for Isaac Newton’s work on universal gravitation, by which we now understand (to a certain extent) what gravity is.
  • He was the first to explain that the tides are caused by the moon. Now we use that detail to predict the tides and know when and how much they will come in and go out.
  • Kepler calculated the year of Christ's birth, and it is his date which is now universally accepted.
  • He coined the word 'satellite' in his pamphlet called Narratio de Observatis a se quatuor lovis sattelitibus erronibus. Now it is a household term and very handy in physics, particularly when talking about gravity and celestial motion.
Nearly everything we know (or think we know) about interplanetary motion and gravity is known, at least in part, because of Kepler.

Works Cited

Lamont, A. (1992, December). Johannes Kepler: Outstanding Scientist and Committed Christian. Retrieved February 19, 2009, from http://www.answersingenesis. org/creation/v15/i1/kepler.asp
Davis, A. E. L. (2006, October). Kepler's Planetary Laws. Retrieved February 19, 2009, from
National Aeronautics and Space Administration (December 1, 2008). Johannes Kepler: His Life, His Laws and Times. Retrieved February 26, 2009 from