Rob's Blog

Recently I stumbled across two rather impressive bits of free software that I was surprised I hadn’t heard of before. The first is Celestia, in their words, a “real-time space simulation that lets you experience our universe in three dimensions.” You can fly around the solar system by right clicking on a planet and selecting “Go To” from the context menu. Or you can use flight sim-like controls to set your speed and direction. You can visit stars and even distant galaxies in the same way. And there’s the celestial browser for searching through catalogues of objects including asteroids, artificial satellites like the ISS, comets, moons, planets and stars.

All the objects are lovingly rendered in Open GL. The viewpoint can be rotated and zoomed; time can be accelerated or slowed down; and orbits and constellations can be overlayed on the view. There’s really not much you could want it to do that it can’t do.

It strikes me as an extremely useful teaching aid, too, so forward the link to any teachers you know! Possible lessons might include a tour of the solar system; a look at the orbits of planets and the distances involved; the phases of the moon as demonstrated by looking at the moon from the Earth which casts an accurately calculated shadow; or a tour of the constellations including how they look from other star systems.

It’s even possible to download the orbits of new objects and add them in. For example, Selden has addons of near Earth objects that occasionally come alarmingly close!

The second program I discovered in a similar vein was XPlanet – which renders a real-time image of the Earth from space on your desktop. You can set the lattitude and longitude to view the bit of the Earth you’re interested and the shadow from the sun is drawn according to the current date and time. You can set it to update, for instance, every five minutes. Using Hans Ecke’s scripts you can even download an updated clouds image generated from satellite photos every three hours! It’s also possible to add overlays with information about satellite orbits, weather, earthquakes and volcanoes, all updated regularly from the web. Much better than boring, static wallpaper.

Both these programs are licensed under the GPL and both work under Linux and Windows.

This entry was posted on Monday, October 27th, 2003 at 7:55 pm and is filed under Links. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.