Intro to Science

4. A smaller body that orbits a planet.
6. The name given to 2 probes launched by NASA to study outer Solar System and eventually interstellar space.
9. A galaxy that does not have a regular shape, like a spiral or an elliptical galaxy.
11. A collection of large and small bodies that orbit our central star, the sun. (2 words)
15. A spherical body that orbits the sun.
16. The path of a celestial body or an artificial satellite as it revolves around another body.
17. Space and all of the energy and matter in it.
19. The process by which nuclei of small atoms combine to form a new, more massive nucleus; the process releases energy. (2 words)
21. Of or relating to the sky or the heavens
23. A dense concentration of galaxies.
24. A large galaxy that contains hundreds of billions of stars.

1. A layer in the earth's stratosphere containing a high concentration of ozone gas, which absorbs most of the UV radiation reaching the earth from the sun. (2 words)
2. A mixture of gases that surround a planet moon or space object.
3. A small galaxy that contains as few as 100 million stars.
5. A force of attraction between objects that is due to due to their masses.
7. Empty areas in space.
8. A large celestial body that is composed of gas and emits light.
10. A galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile.
12. A group of 10 or more galaxy clusters.
13. A molecule that is made of 3 oxygen molecules.
14. An optical instrument designed to make distant objects appear nearer.
18. A large collection of stars, gas, and dust that is held together by gravity.
20. A galaxy in which the stars and gas clouds are concentrated mainly in one or more spiral arms.
22. A telescope orbiting Earth that was launched in 1990.