Space Vocab

3. a measure of how oval-shaped an orbit is (the more circular the orbit, the LESS eccentric it is)
6. an object’s orbital motion around another object
11. an astronomical object consisting of a luminous spheroid of plasma held together by its own gravity
12. the change in frequency of a wave (or other periodic event) for an observer moving relative to its source
18. Earth-like planets made up of rocks or metals with a hard surface
20. the whole cosmic system of matter and energy of which Earth is a part
21. the daily changes in the level of the ocean water at any given place

1. a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity
2. a regular, repeating path that one object in space takes around another
4. the beginning of the universe as one single point that stretched and expanded into what it is now
5. any of the four largest planets in our solar system, on the far side the asteroid belt, furthest from the Sun
7. a celestial body that is in orbit around a Sun and has a nearly round shape
8. one of two points inside an ellipse (oval) that determine the shape of its curve
9. an object’s spinning motion around its own axis
10. a moon, planet or machine that orbits a planet or star
13. the partial or total blocking of light of one celestial object by another
14. a cosmic snowball of frozen gases, rocks, and dust that orbits the Sun
15. an invisible line around which an object rotates or spins
16. a streak of light in the sky caused by a space rock crashing through Earth’s atmosphere
17. the universal force of attraction acting between all matter
19. a small rocky body orbiting the sun