test vocabulary

3. has an elliptical shape, very little gas and dust, and is filled with old red stars that have random orbits in multiple planes
7. Orbits the center of the galaxy at about 515,000 mph
9. the explosion of a very large star in which the star temporarily gives off up to one billion times more energy than the sun
11. An enormous ccloudof dust and gas occupying the space between stars and acting as a nursery for new stars
13. measured by the acceleration that it gives to freely falling objects
14. meter, kilogram, second

1. the available body of facts or information indicating whether a belief or proposition is true or valid
2. a large barred spiral galaxy
4. the average distance between Earth and the Sun,
5. all existing matter and space considered as a whole; the cosmos.
6. a region of space having a gravitational field so intense that no matter or radiation can escape.
7. a structure suggested by these laws and is devised to explain them in a scientifically rational manner
8. ypically has a rotating disc with spiral 'arms' that curve out from a dense central region
10. the distance light travels in one year
12. a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.