What is the best free astronomy software?

Do you like astronomy? Let me suggest you some free apps that may help you to enjoy and learn about the Solar System, the Milky Way, and the Universe.

• Google Earth is the most photorealistic, digital version of our planet. Google Earth is currently available for download as a desktop application. With one click of the mouse on the planets icon at the top of Google Earth, you can switch to Sky Mode. It allows you to navigate through space and explore planets, stars, and galaxies. You can also visit Google Sky from your browser.
• Celestia is a real-time space simulation that lets you explore our universe in three dimensions. It is free, open source and multiplatform.
• Orbiter is a free and realistic space flight simulator for Windows with a twist, it actually obeys the laws of physics.
• Sky-Map.org is a map of the night sky that shows the location of stars, constellations, planets and other celestial bodies.

Sky Map is a hand-held planetarium for your Android device. SkyWiki is a full-featured, free astronomy app. Star Walk Kids is a child-friendly version of Star Walk. Star Walk is a very popular stargazing app.

Children’s University of Manchester (Science, The Earth and Beyond) is truly a website worth looking at. For instance, you can read that “The Earth is about 4 times bigger than the Moon.”