Free planets software for linux

Planets is a simple interactive program for playing with simulations of planetary systems, released under the GPL. The project runs on Linux and Windows, and could doubtless be ported to your favorite flavor of Unix.
Planets was originally designed for kids, in particular, for my then 4-year old nephew who is fascinated by astronomy. The user interface is aimed at being simple enough that a fairly young kid can get some joy out of it. But the adults who have used it have found it to be pretty fun as well.
The code is not bug-free, and Planets is missing some significant features. But its pretty stable and is a fun toy to play with. If you do download it, please drop me an email and tell me about your experience with it.
Main features:
- Saving and loading of universes
- Infinite undo (erase last action) and goback (return to point in time just after last action). This allows for undoing mistakes and replaying interesting configurations.
- Traces of planet trajectories
- Two ways of dealing with planet collisions:
- merges, where the colliding planets are merged into one planet, and
- bounces, where the colliding planets are bounced off each other elastically. This itself comes in two varieties:
- force bouncing, where the force between planets is made repulsive at close quarters.
- true bouncing, where simple pool-table physics calculations are made to determine when planets collide, and compute the appropriate bounce from said collision.
- kidmode, a mode where the focus is (mostly) locked on the application, and interesting changes are initiated by merely banging on the keyboard. This mode is aimed at 1-5 year olds.
- Center-of-mass following: it is possible to follow the center of mass of a subset of the planets. Thus, if you have a sun-moon-planet system, you can have the view automatically track the moon-planet pair.
- Can display kinetic, potential and total energy of the system.
- Both the gravitational constant and the gravitational exponent can be changed.
- There is a simple control panel that makes it possible to see and change the simulation options.
- Zooming, panning, and centering on the center of mass.

RSS-Planet is a custom marker file generator for xplanet which uses RSS feeds from news websites to plot the current headlines on a world map.

By default, Yahoo! News and CNN.com are supported, but other feeds that point to articles with easily-discoverable place names (such as the Washington Post) should work as well.

PlanetGenesis is a Java program designed to produce models of planets and landscapes.

A little like Mojoworld but free (as in beer and speech) and no where near as good.

PlanetGenesis produces:

- 16bit greyscale bitmaps.
- Wavefront format objects.
- POV-RAY 3.5 mesh2 meshs.
- Terragen terrains.

based on pseudo-random noise. Which can be used in 3D rendering sofware.

Fracplanet is an interactive tool for creating random fractal planets and terrain areas with oceans, rivers, lakes and icecaps.
The results can be saved in POV-Ray format. The code is licensed under the GPL. Fracplanet project uses Qt and OpenGL.
Enhancements:
- The main addition in this release is the ability to export the terrain as a texture map, with or without relief shading.
- A DEM (Digital Elevation Model, or height field) and normal map are also written.
- For planets, the textures are a cylindrically projected latitude/longitude map (this is directly usable as a spheremap in POV-Ray).
- The illumination direction is now controllable from the GUI, and swirly spiral weather systems can be added into the clouds.

Wait no more for a usable system to create a centralized hub, so-called a planet site, of news feeds from selected Web sites, PlanetMatter provides a better choice to aggregate RSS and ATOM feeds of blogs, company news, databases, calendars, articles, and more!

Lastest news items are instantly aggregated and sequentially laid out in one page for readability. Moreover, "full-text" search facility effectively retrieves more related news items according to search terms (keywords).

Features:
PlanetMatter comes with complete feed management features such as

Add, pause, delete, edit feeds
Import feeds to OPML or text
Edit planet site configuration information
and much more!

Installation:
PlanetMatter is relatively easy to install. Please read the INSTALL file for details.

PyNOVAS allows you to calculate the position and movement of the sun, moon, planets, and stars with great precision using Python.
PyNOVAS software is based on the NOVAS software used by United States Naval Office (USNO) to produce the Astronomical Almanac and MICA. Ephemerides are supplied by the Jet Propulsion Laboratory (JPL).
You can use this software for Celestial Navigation, and also as a basis for controlling astronomical equipment.
Enhancements:
- This beta release is based on swig 1.3.24 or higher and Python 2.3 or higher.
- It has more examples, including test.py, eclipse.py, and almanac.py

TerraJ is a Java port of fractal terrain and simulated solar system generation programs.

The porting has included extensive refactoring, the creation of a documented API to enable reuse of parts in other programs, and extensions such as new Swing user interfaces. Full javadoc for the classes in the project is available.

The TerraJ suite currently contains the following software:

- Fracplanet - Generates fractal planets and terrains with a wide range of user controlled parameters. Has an OpenGL rendering preview using JOGL and can export to POVRay format for rendering.

- Stargen - Creates realistic planetary systems and stars using an accretion simulation. The resulting text and HTML output is template based and configurable.

- Planetary Terrain Generator - A second fractal terrain generation program. This one does not do 3D rendering but can output images using many different map projections.

- Dole Accretion - An older and slightly less complex star system generator included for reference and completeness.