1. Beyond the scope of normal scientific understanding

2. Extraterrestrial being

3. Extraterrestrial guests

4. Difficult to explain or understand

5. Vehicle designed for space travel

6. Living forever; never dying

7. Close or near in space or time

8. Unidentified flying object

9. Path of a celestial object around another

10. Strange or frightening

11. Fictional friendly alien

12. Planet located outside our solar system

13. Person who travels in space

14. Focused ray of light or energy

15. Top secret US military facility

15. Kidnap by aliens

16. Acronym for extraterrestrial