Outer space

2. Prefixed with the Latin indicator for "between," this term means situated between vast systems of stars.
5. Morphologically structured from Greek roots to mean "earth-centered".
7. Derived from Latin roots meaning "sun stands still", denoting the two times a year when the sun reaches its highest or lowest point.
9. Blends the Greek root for an "orderly universe" with the suffix for "the study of" to yield "the study of the universe".
11. Merges the Greek root for "air" with a word for physical expanse to describe the boundary of aviation and space flight.
12. Combines a prefix meaning "extremely small" with a physical force to describe a state of apparent weightlessness.
13. Uses the suffix meaning "resembling" attached to a Greek root for "high in the air" to describe a small, rocky body in space.
15. Combines a prefix meaning "between" with the Latin root for "star" to mean "situated between the stars".
17. This mathematical term stems from ancient Greek roots literally meaning "earth measurement".
19. Melds a Latin prefix meaning "around" with a root meaning "moon" to describe an object moving or revolving around the moon.

1. Formed from the Greek roots for "star" and "sailor", this word literally translates to "star sailor".
3. Stemming from the Greek root kometes, this icy celestial object literally means "long-haired star".
4. Affixes a suffix meaning "one that performs an action" to a Latin root for a circular track, describing a spacecraft that circles a planet.
6. Takes the Latin root for "cloud" and adds a suffix meaning "full of" to describe something hazy, vague, or cloud-like.
8. Combines the prefix for "far away" with the root for "to watch" to form an instrument that looks at distant objects.
10. Built from the Greek root for "sun" paired with "sphere", it describes the vast magnetic bubble surrounding our solar system.
11. Built from Greek roots meaning "vapor sphere", it describes the envelope of gases surrounding a planet.
14. Literally translating from Latin as "stars together", it describes an official pattern or group of celestial bodies.
16. Prefixed with the Greek indicator for "against" or "opposite," it describes a hypothetical force that cancels out weight.
18. Combines the prefix for "large or great" with the root for "universe" to describe the universe as a whole, complex structure.