Across
- 3. icy, small Solar System body
- 5. a small planetary-mass object that is in direct orbit of the Sun
Down
- 1. how astronomers explain the way the universe began
- 2. a layer of gas or layers of gases that envelop a planet
- 4. the range of frequencies of electromagnetic radiation
- 6. an invisible line around which an object rotates, or spins
- 7. minor planet of the inner Solar System