Wikipedia
SpaceEngine (stylized as "Space Engine") is a proprietary 3D astronomy program and game engine developed by Russian astronomer and programmer Vladimir Romanyuk. Using real astronomical catalogs and procedural generation, it creates a three-dimensional planetarium representing the entire universe. Users can travel through space in any direction or speed, and forwards or backwards in time. SpaceEngine is in beta status, and is currently freeware for Microsoft Windows. It uses pseudo-random numbers to procedurally create any kind of planetary system, nebula or galaxy.
One of the main features of the program is its scientific accuracy. Cataloged objects are based on real data, while procedural objects are built around the cataloged universe using realistic generation algorithms. Properties of objects, such as temperature, mass, radius, etc., are presented to the user on the HUD and in an accessible information window. Users can observe objects from small spacecraft to galaxy clusters, similar to other simulators such as Celestia. SpaceEngine includes thousands of real objects, including stars from the Hipparcos catalog, galaxies from the NGC and IC catalogs, several well-known nebulae, and all known exoplanets and their stars.