1. Its first attempt at an unmanned mission to the red planet could take place as early as 2018.

2. The former Soviet Union reached the planet in 1971, and the European Space Agency in 2003.

3. This is the only nation on the planet that was an idea.

4. Facebook is the largest social network on the planet and wants to stay that way.

5. The spacecraft was sent to study the face of the planet and to model its interior.

6. It seems this would also make each planet appear more lively.

7. Scientists have studied the possibility that there was a planet in this system for years.

8. The early results have produced fresh data on the planet that have scientists excited.

9. When you land on another planet, normally you have to do a lot to protect your rover.

10. We really have to move off this planet, he suggested.

11. The iPhone is the single most popular phone on the planet, but what everyone wants is big phones.

12. Now that would be a true benefit to everyone on this planet, he concluded.

13. Their target would be a planet with potential for holding life.

14. Finding life at high altitude in the atmosphere of a planet would make sense.

15. The farther away a planet lies from its sun, the easier that world is to identify.