- Scientists estimate that there are at least six billion planets that are similar to our Earth, present within our Milky Way galaxy alone. Some estimate that there are more than 10 billion. https://nineplanets.org/questions/how-many-planets-are-in-the-milky-way/ 143 comments space
- Mars can have a ring in future. Phobos, a moon of Mars, orbits the planet below the synchronous orbit and could either crash into Mars's surface or break up into a ring structure around the planet in 50 million years. https://nineplanets.org/phobos/ 37 comments space
- interactive tour of our Solar System http://nineplanets.org/tour/ 5 comments space