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Featured Tool:
The Sun appears to us constant and unchanging. But over billions of years, it evolves dramatically. How? Find out by watching the
Sun's Life!



Saturn Ratings

  • Astronomy Classroom
  • Explore the Possibilities
  • Solar System Calculators
  • Solar System Viewers
  • Working With Orbits
  • Orbital Integrators
  • Extragalactic
  • Index of all Tools


  • Tuesday's
    Astro Fact:
    Did you know that every hundred million years or so, a violent collision of a sizable comet or asteroid with the Earth is likely to occur? More...
    visits to the Astronomy Workshop since January 1st, 2000. 

    Materials for Students and Instructors.

    Created by Dr. Douglas P. Hamilton and students at U. Maryland. We gratefully acknowledge support from NSF (1998-2003) and NASA (2003-2010). About Us