Night Sky with Stars


Foothill College AstroSims

The Foothill Astrosims project aims to support astronomy education by:

  • Updating existing educational simulations from Flash to Javascript, and
  • Develop new simulations to address topics formerly unsupported by the Astronomy Education community

Our Simulations

We are steadily working on new simulations.  Check here for updates!

Who are we?

  • PI: Geoff Mathews, Ph.D. (
  • Development lead: Baba Kofi Weusijana, Ph.D. (
  • Development team, Winter and Spring 2020:  Chris Achenbach, Safi Mohammed, Andrew Tran



Other Astronomy Simulations

We maintain a list of Astro-education simulations by topic.  The first sheet matches Flash simulations from the largest collection - the University of Nebraska at Lincoln - to HTML5 simulations that accomplish the same tasks.  The second sheet lists simulations addressing further topics.   

Here we list collections of simulations and individual simulations written in modern frameworks (e.g., HTML5).  Simulations in Flash and Java are noted.  

  • Collections
    • Flash The Nebraska Astronomy Applet Project has a set of simulations covering a wide range of topics in astronomy.  They are Flash-based, and thus rapidly becoming unusable.  However, they have recently posted Windows- and Mac-native versions of the applets to sustain classroom use, and have created HTML5 versions of a few of their simulations.  
    • A team at Columbia University has rebuilt several of the UNL simulations in Javascript, and provides useful guidance for carrying out further conversions.  
    • The University of New Mexico hosts a set of simulations written by Kevin Dilts addressing a variety of topics.  
    • The GEAS Project at NMSU (Nicole P. Vogt) has several simulations and data interpretation tools - with labs! - including a replication of the NAAP HR Diagram explorer and a galactic redshift simulator.  
    • The PhET Simulations, while physics focused, include numerous tools that are helpful for astronomy teaching (for example, Gravity and Orbits).  Some of their simulations have not yet been updated from Flash and Java.
    • Open Source Physics has numerous astro-useful simulations in JavaScript.  
    • ScienceSims at CCNY has an entire section of astronomy simulations. 
    • Andrew Duffy at Boston University has written a large set of Javascript simulations, including spectroscopy and optics. 
    • A nice set of HTML5 simulations from Michael Fowler at the University of Virginia.
    • A large number of astronomy simulations, written in Mathematica, have been posted with Wolfram Cloud.  Most of these will work in browser, but many were optimized for use in a dekstop app.
    • Some of the sample models included with Netlogo address astronomy relevant topics (e.g., motion of particles in a gas).  This modeling tool is also designed with an easy on-ramp for developing ones own simple  simulations.
    • Java Javalab is now defunct.  However, the code is available and Chris Mihos welcomes reimplementations (with credit, of course!)
  • Individual simulations and tools
    • Heather Flewelling has made an RGB image constructor using images from the Pan-STARRS telescope.  
    • Rick Tu has written a very thorough optics ray-tracing application.
    • Flat-Earth simulator illustrates how the sun's apparent size and altitude would vary if the Earth was flat.
    • Star in a Box, by the Las Cumbres Observatories Global Telescope Network, simulates tracking a star's temperature and luminosity over its lifetime.  
    • Ian Short at St. Mary's University has made an incredibly thorough star + habitable zone simulator, ChromaStar.
    • 100,000 Stars, a visualization of about 100,000 nearby stars (plus some artistic license on larger scales).  Note, it doesn't appear to make use of color or luminosity information, only position and distance.
    • Super Planet Crash is a game-ified n-body solar system simulator in which one can explore gravitational interactions between planets.  
    • Planetary climate simulator from the NExSS ROCKE-3D project at NASA Goddard.
    • A different planetary climate simulator, emphasizing geologic processes, from the Earth Life Science Institute.  
    • Flash Impact Earth simulator (there is a text-only version, as well)
    • Flash The Interactive Comet Animation at the Windows to the Universe site allows you to adjust a comet's orbit and see the formation and dissipation of the dust and ion tails.
    • Thomas Moore has written a rotation curve tool allowing one to adjust a three-parameter dark matter distribution model to match observed rotation curves.   
    • John Walker's simulation of an orbit in strongly curved spacetime

Please email us with other simulations to include on the list!  Contact Geoff Mathews at



AstroSims was supported in Winter and Spring quarters of 2020 by a Foothill College Equity and Innovation Grant

AstroSims Highlight

Just how far away are distant galaxies?  Explore three ideas - the distance to a galaxy when light started its journey, how far the light travelled to reach us, and how far away the galaxy is now - with the Cosmological Redshift Simulation.

Cosmological Redshift simulator


Want to know more about AstroSims?  

Contact Geoff Mathews, at

Geoff Mathews

David Marasco

We're Here to Help!

David Marasco, Dept. Chair


Office Room 4405