sci-astronomy Celestia is a real-time space simulation that lets you experience our universe in three dimensions. You can travel throughout the solar system, to any of over 100,000 stars, or beyond the galaxy. All travel in Celestia is seamless; the exponential zoom feature lets you explore space across a range of scales, from galaxy clusters down to spacecraft a few meters across. A 'point-and-goto' interface is used to navigate through the universe to the object you want to visit.